Current Issue

2024 Vol. 40, No. 11

Expert Forum
Recognition of inhalation injuries
Guo Guanghua, Huang Shengyu
2024, 40(11): 1001-1006. doi: 10.3760/cma.j.cn501225-20240616-00234
Abstract:
Inhalation injury, with a certain incidence rate and a high mortality in clinic, has always garnered the attention of various healthcare professionals. In recent years, while the incidence rate of burns with inhalation injury has been decreasing, the treatment of inhalation injury should not be overlooked, as there is still room for improvement in its diagnosis and treatment. With the deepening understanding of inhalation injury mechanisms and the continuous emergence of new concepts about lung injury, it may offer insights and strategies for clinical diagnosis and treatment of inhalation injury. This paper addresses some of these insights and concepts from the perspectives of molecular mechanisms, diagnostic evaluations, and treatment of inhalation injury for the reference of our colleagues.
Strategies for the diagnosis and treatment of inhalation injuries in children
Yu Jia'ao, Zhang Xiuhang
2024, 40(11): 1007-1015. doi: 10.3760/cma.j.cn501225-20240816-00310
Abstract:
In the expansive field of burn medicine, inhalation injury, as one of the complex and challenging issues, has consistently captured the attention of the burn community. With the comprehension of inhalation injury has becoming increasingly profound and comprehensive, the complexity of their conditions and the uniqueness of their treatment options become especially significant when our attention is focused on the special group of children. The objective of this paper is to examine the intricate causes of inhalation injuries in children, with a particular emphasis on the distinctive characteristics of inhalation injuries in children and the subtle alterations in their pathophysiological mechanisms. In light of the aforementioned considerations, we further explore and discuss the precise diagnostic methods and efficacious therapeutic options for this type of injury, aiming to provide strong support for the research development and practical applications in this field, and to facilitate the knowledge update and technological innovation in this domain.
Respiratory care for burn-related lung injury--shoulder heavy responsibilities, and a long way to go
Zhu Feng, Guo Guanghua
2024, 40(11): 1016-1023. doi: 10.3760/cma.j.cn501225-20240802-00291
Abstract:
Burns is often accompanied by respiratory tract and lung injuries, which seriously affects the prognosis and treatment effect of such patients. Respiratory care refers to the prevention, evaluation, diagnosis, treatment, management, and care of patients with cardiopulmonary insufficiency or abnormalities under the guidance and cooperation of professional doctors, which is an important part of acute respiratory distress syndrome treatment and is also gradually applied in burn-related lung injuries. Respiratory care covers prevention and treatment, and interacts with burn wound repair and overall rehabilitation, which requires more attention, research, and practice from practitioners. Under the background of the rapid development of respiratory care and the relatively limited burn-related lung injury research and practice, this paper tries to elaborate and analyze the significance of respiratory care for burn-related lung injury, specific measures, and shortcomings, aiming to encourage more practitioners to study and participate in depth, and through accumulation and summary, to achieve the purpose of scientific and standardized implementation of respiratory care for burn-related lung injury.
Original Article · Burn and Trauma Related Lung Injury
A multicenter study on the impact of the early infusion rate on prognosis and the factors of influencing the infusion rate in patients with severe burns and inhalation injury
Huang Shengyu, Ma Qimin, Wang Yusong, Tang Wenbin, Chu Zhigang, Xin Haiming, Chang Liu, Li Xiaoliang, Guo Guanghua, Zhu Feng
2024, 40(11): 1024-1033. doi: 10.3760/cma.j.cn501225-20240409-00130
Abstract:
  Objective  To investigate the impact of the early infusion rate on prognosis and the factors of influencing the infusion rate in patients with severe burns and inhalation injury.  Methods  This study was a retrospective case series research. From January 2015 to December 2020, 220 patients with severe burns and inhalation injury meeting the inclusion criteria were admitted to 7 burn treatment centers in China, including 13 cases in the Fourth People's Hospital of Dalian, 26 cases in the First Affiliated Hospital of Naval Medical University, 73 cases in Guangzhou Red Cross Hospital of Jinan University, 21 cases in the 924th Hospital of PLA, 30 cases in the First Affiliated Hospital of Jiangxi Medical College of Nanchang University, 30 cases in Tongren Hospital of Wuhan University & Wuhan Third Hospital, and 27 cases in Zhengzhou First People's Hospital. There were 163 males and 57 females, and their ages ranged from 18 to 91 years. The patients were divided into survival group and death group according to the survival within 28 d post injury. The following data of patients in the 2 groups were collected, including basic information (gender, age, body weight, body temperature, etc.), the injury characteristics (total burn area, post-injury admission time, etc.), the underlying diseases, the post-injury fluid resuscitation condition (infusion rate and ratio of infused electrolyte solution to colloid solution in the first 24 h post injury, etc.), the results of laboratory tests on admission (blood urea nitrogen, blood creatinine, albumin, pH value, base excess, blood lactate, oxygenation index, etc.), and treatment condition (inhaled oxygen volume fraction, hospitalization day, renal replacement therapy, etc.). After adjusting covariates using univariate Cox regression analysis, the multivariate Cox regression analysis was performed to evaluate the impact of infusion rate in the first 24 h post injury on patient death. The receiver operator characteristic curve for the infusion rate in the first 24 h post injury to predict the risk of death was plotted, and the maximum Youden index was calculated. Patients were divided into 2 groups according to the cutoff value (2.03 mL·kg-1·% total body surface area (TBSA)-1) for predicting risk of death by the infusion rate in the first 24 h post injury determined by the maximum Youden index, and the risk of death was compared between the 2 groups. The correlation between the previously mentioned clinical data and the infusion rate in the first 24 h post injury was analyzed; after the univariate linear regression analysis was used to screen the independent variables, the multivariate linear regression analysis was performed to screen the independent influential factors on the infusion rate in the first 24 h post injury.  Results  Compared with those in survival group, patients in death group had significantly higher age and total burn area (with Z values of 12.08 and 23.71, respectively, P<0.05), the infusion rate in the first 24 h post injury, inhaled oxygen volume fraction, and blood urea nitrogen, blood creatinine, blood lactic acid on admission (with Z values of 7.99, 4.01, 11.76, 23.24, and 5.97, respectively, P<0.05), and the proportion of patients treated with renal replacement therapy (P<0.05) were significantly higher, the albumin, pH value, and base excess on admission were significantly lower (t=2.72, with Z values of 8.18 and 9.70, respectively, P<0.05), and the hospitalization day was significantly reduced (Z=85.47, P<0.05). After adjusting covariates, the infusion rate in the first 24 h post injury was the independent influential factor on death (with standardized hazard ratio of 1.69, 95% confidence interval of 1.21-2.37, P<0.05). Patients in infusion rate ≥2.03 mL·kg-1·%TBSA-1 group had a significantly higher risk of death than those in infusion rate <2.03 mL·kg-1·% TBSA-1 group (with hazard ratio of 3.47, 95% confidence interval of 1.48-8.13, P<0.05). There was a significant correlation between total burn area, body weight, inhaled oxygen volume fraction, body temperature, post-injury admission time, the ratio of infused electrolyte solution to colloid solution in the first 24 h post injury, and oxygenation index <300 on admission and the infusion rate in the first 24 h post injury (with r values of -0.192, -0.215, 0.137, -0.162, -0.252, and 0.314, respectively, Z=4.48, P<0.05). After screening the independent variables, total burn area, body weight, post-injury admission time, and oxygenation index <300 on admission were the independent influential factors on the infusion rate in the first 24 h post injury (with standardized β values of -0.22, -0.22, -0.19, and 0.46, respectively, 95% confidence intervals of -0.34 to 0.09, -0.34 to 0.10, -0.32 to 0.06, and 0.22 to 0.71, respectively, P<0.05).  Conclusions  The infusion rate in the first 24 h post injury in patients with severe burns and inhalation injury is the independent factor of influencing death, and patients with infusion rate ≥2.03 mL·kg-1·%TBSA-1 in the first 24 h post injury have a significantly increased risk of death. The total burn area, body weight, post-injury admission time, and oxygenation index <300 on admission were the independent factors of influencing the infusion rate in the first 24 h post injury in patients with severe burns and inhalation injury.
Role and mechanism of ferroptosis in combined burn-blast injury with acute lung injury in rats
Zhang Hao, Guan Hao, Wang Yuhang, Zhang Wanfu, Tian Linqiang, Ren Wenjie
2024, 40(11): 1034-1042. doi: 10.3760/cma.j.cn501225-20240528-00199
Abstract:
  Objective  To investigates the role and mechanism of ferroptosis in combined burn-blast injury with acute lung injury in rats.  Methods  This study was an experimental study. Twenty-four 8-week-old male Sprague-Dawley rats were divided into control group and experimental group by random number table method, each containing 12 animals. The rats in experimental group were anesthetized and subjected to explosion treatment to create the model of combined burn-blast injury with acute lung injury, whereas the rats in control group underwent sham injury. At 24 hours post injury, the pathological morphology of lung tissue was observed by hematoxylin-eosin staining and immunohistochemical staining. The levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6 in the supernatant of bronchoalveolar lavage fluid (BALF) were detected by enzyme-linked immunosorbent assay. The arterial partial pressure of oxygen (PaO2) and arterial partial pressure of carbon dioxide (PaCO2) of abdominal aortic blood were measured by automatic animal blood gas analyzer. The lung tissue was weighed and the wet-dry weight ratio was calculated. The total protein concentration in BALF was measured by bicinchoninic acid assay. Lung injury was scored based on hematoxylin-eosin staining. The levels of oxidative stress factors, such as reactive oxygen species, malondialdehyde, superoxide dismutase (SOD), glutathione, and ferrous ion in lung tissue homogenate of rats were detected by related kits. The expression levels of ferroptosis-related molecule glutathione peroxidase 4 (GPX4), lipid peroxidation-related molecule 4-hydroxynonenal (4-HNE), and oxidative DNA damage-related molecule 8-hydroxydeoxyguanosine (8-OHdG) in lung tissue were detected by immunofluorescence and immunohistochemistry methods. Mitochondrial morphology in lung tissue cells was observed under transmission electron microscopy. The sample number was all 6.  Results  At 24 hours post injury, the lung tissue structure of rats in control group was clear and complete, and the alveolar wall was normal; in experimental group, the lung tissue edema of rats was obvious, the alveolar wall became thicker, and the structure was not clear. At 24 hours post injury, compared with those in control group, the levels of TNF-α, IL-1β, and IL-6 in BALF supernatant of rats in experimental group were significantly increased (with t values of 3.96, 9.84, and 10.60, respectively, P<0.05); the wet-dry weight ratio of lung tissue, lung injury score, and total protein concentration in BALF of rats in experimental group were significantly increased (with t values of 6.91, 6.64, and 10.04, respectively, P<0.05), PaO2 of abdominal aortic blood decreased significantly (t=8.85, P<0.05) while PaCO2 did not change significantly (P>0.05); the levels of SOD and glutathione in the lung tissue homogenate of rats in experimental group were significantly decreased (with t values of 4.36 and 8.56, respectively, P<0.05), while the levels of reactive oxygen species, malondialdehyde, and ferrous ion were significantly increased (with t values of 11.55, 9.78, and 14.77, respectively, P<0.05). At 24 hours post injury, immunofluorescence staining and immunohistochemical staining showed that the expression levels of GPX4 in lung tissue of rats in experimental group were 0.245±0.024 and 0.786±0.240, respectively, which were significantly lower than 1.000±0.305 and 1.000±0.200 in control group (with t values of 6.05 and 2.60, respectively, P<0.05); the expression levels of 4-HNE in lung tissue of rats in experimental group were 5.93±1.05 and 2.21±0.23, respectively, which were significantly higher than 1.00±0.29 and 1.00±0.23 in control group (with t values of 11.13 and 9.16, respectively, P<0.05); the expression levels of 8-OHdG in lung tissue of rats in experimental group were 2.08±0.40 and 1.61±0.29, respectively, which were significantly higher than 1.00±0.40 and 1.00±0.26 in control group (with t values of 4.72 and 3.87, respectively, P<0.05). At 24 hours post injury, compared with that in control group, the density of mitochondrial double-layer membrane in the lung tissue cells of rats in experimental group increased, the outer membrane ruptured, and the crista decreased.  Conclusions  In rats with combined burn-blast injury with acute lung injury, there is oxidative DNA damage in lung tissue cells, the imbalance of antioxidant system in lung tissue, and a decrease in the expression of GPX4, the key molecule against ferroptosis, suggesting that ferroptosis is involved in the pathophysiological process of this disease.
Two-sample Mendelian randomization analysis of the causal relationship between human inhalation injury and circulating inflammatory proteins
Dai Zhanzhan, Zhu Qin, Tong Xirui, Ma Bing, Xia Zhaofan, Fang He
2024, 40(11): 1043-1051. doi: 10.3760/cma.j.cn501225-20240429-00155
Abstract:
  Objective  To explore the causal relationship between human inhalation injury and circulating inflammatory proteins.  Methods  This research was based on two-sample Mendelian randomization (MR) analysis. With inhalation injury as the exposure factor and circulating inflammatory proteins as the result, data on inhalation injury (216 993 samples) and 91 circulating inflammatory proteins (14 824 samples) were obtained from the genome-wide association study database, and analysis was conducted by two-sample MR analysis methods. Based on linkage disequilibrium analysis, independent site single nucleotide polymorphisms (SNPs) that were significantly associated with inhalation injury were identified as the instrumental variables. The inverse variance weighted (IVW) method was mainly used to analyze the causal relationship between inhalation injury and 91 circulating inflammatory proteins, which were further verified using the weighted median method, weighted pattern method, MR-Egger method, and simple pattern method. Based on the aforementioned IVW method analysis results, SNPs of inhalation injury conformed to the hypothesis were subjected to Cochran's Q test for heterogeneity assessment, the MR-Egger regression test and MR-PRESSO outlier test for assessment of horizontal pleiotropy, and the leave-one-out method analysis for reliability assessment.  Results  Six SNPs with a significant threshold (P<5×10-5) were identified as representative instrumental variables of inhalation injury, with F values greater than 10, indicating strong correlated instrumental variables. Based on the 6 inhalation injury SNPs, the IVW method analysis revealed a significant causal relationship between inhalation injury and interleukin-20 (IL-20), IL-20 receptor subunit alpha (IL-20RA), IL-5, and tumor necrosis factor receptor superfamily member 9 (TNFRSF9), with odds ratios of 1.01, 1.01, 1.02, and 1.01, respectively, and 95% confidence intervals of 1.00-1.02, 1.00-1.03, 1.01-1.03, and 1.00-1.03, respectively, P<0.05. Verification through the weighted median method and MR-Egger method confirmed that the causal relationships between inhalation injury and IL-5 (with odds ratios of 1.02 and 1.03, respectively, confidence intervals of 1.00-1.04 and 1.01-1.04, respectively, P<0.05) as well as TNFRSF9 (with odds ratios of 1.02 and 1.03, respectively, confidence intervals of 1.00-1.04 and 1.01-1.04, respectively, P<0.05) were statistically significant. Conversely, verification through the weighted pattern method and simple pattern method indicated that the causal relationships between inhalation injury and IL-20, IL-20RA, IL-5, and TNFRSF9 were not statistically significant (with all P values >0.05), thus still needing IVW method results as standards. Based on the aforementioned IVW method analysis results, the Cochran's Q test demonstrated there was no significant heterogeneity in the 6 inhalation injury SNPs that had significant causal relationships with IL-20, IL-20RA, IL-5, and TNFRSF9 (with Q values of 2.67, 5.00, 5.17, and 5.29, respectively, P>0.05); assessments using the MR-Egger regression test along with MR-PRESSO outlier test showed that none of the 6 inhalation injury SNPs that had significant causal relationships with IL-20, IL-20RA, IL-5, and TNFRSF9 had significant horizontal pleiotropy (with intercepts of 0.01, <0.01, -0.02, and -0.03, respectively, RSSobs values of 3.33, 9.00, 7.88, and 7.26, respectively, P>0.05); the leave-one-out method analysis showed that the significant causal relationship between inhalation injury and IL-20, IL-20RA, IL-5, and TNFRSF9 was stable and reliable after removing the 6 inhalation injury SNPs one by one.  Conclusions  Through two-sample MR analysis, it is clear that there is a significant causal relationship between inhalation injury and four circulating inflammatory proteins, namely IL-20, IL-20RA, IL-5, and TNFRSF9, suggesting the production of the above four circulating inflammatory proteins is in an increasing trend following inhalation injury.
Original Article
Effects of thinned anterolateral thigh perforator flaps combined with finger splitting and webplasty in sequential treatment of degloving destructive wound of total hand
Yin Shanqing, Zhu Feng, Huang Yaopeng, Pan Jiadong, Xiao Dongchao, Liu Linhai, Li Xueyuan, Wang Xin
2024, 40(11): 1052-1058. doi: 10.3760/cma.j.cn501225-20240723-00275
Abstract:
  Objective  To investigate the effects of thinned anterolateral thigh perforator flaps combined with finger splitting and webplasty in sequential treatment of degloving destructive wound of total hand.  Methods  This study was a retrospective observational study. From January 2012 to January 2023, a total of 15 cases who met the inclusion criteria with degloving destructive wound of total hand were admitted to Ningbo No.6 Hospital, including 10 males and 5 females, aged 17-75 years. The wounds were all combined with exposed bones or tendon. Emergency debridement and vacuum sealing drainage were performed in all cases before flap transplantation in stage Ⅰ. After thorough debridement, the wound area was 11.0 cm×3.0 cm-23.0 cm×13.5 cm. One or both anterolateral thigh perforator flaps with size of 12.5 cm×5.0 cm-25.0 cm×15.5 cm were designed, cut, and thinned to repair the skin and soft tissue defects of the hand. The donor site was sutured directly or repaired with medium-thickness skin graft from the opposite thigh. As needed, the flap was reconstructed by finger splitting and webplasty once or more times every 3 months after stage Ⅰoperation. The survival and complications of flap and wound healing at the donor site were observed after stage Ⅰoperation. The appearance of flap, two-point discrimination distance, and hand function were observed during the follow-up. At the final follow-up, the function of the affected hand was evaluated by the trial standards for evaluation of partial function of upper extremity by the Hand Surgery Society of Chinese Medical Association.  Results  After the operation of stage Ⅰ, all the flaps of 15 cases of patients survived completely, including 1 case that had arterial crisis of flap but survived completely after exploration and re-anastomosis of blood vessels; all the wounds at the donor site healed. During the follow-up period of 6 to 18 months after stage Ⅰ, the flap was slightly swollen, with a little pigmentation, and the two-point discrimination distance in the finger flap was 8-11 mm. The fingers could complete the basic life actions such as flexion, extension, pinch, and grip. At the final follow-up, 3 cases were excellent, 9 cases were good, and 3 cases were acceptable in function evaluation of the affected hand.  Conclusions  For degloving destructive wound of total hand, free transplantation of one or both thinned anterolateral thigh perforator flaps is used for repair in stage Ⅰ, and finger splitting and webplasty are used to reconstruct the flaps in the later stage, which can basically restore the pinch and grip function of the affected hand that is required for daily life, and is worthy of clinical promotion.
Comparative study on patients with combined burn-blast injuries caused by liquid plastic and liquid metal foreign objects in the body
Ke Jiaxiang, Yu Fengge, Li Ning, Bian Xi, Deng Ruomeizi, Li Bei
2024, 40(11): 1059-1065. doi: 10.3760/cma.j.cn501225-20240327-00107
Abstract:
  Objective  To compare the clinical characteristics, diagnostic plans, and treatment strategies of patients with combined burn-blast injuries caused by liquid plastic and liquid metal foreign objects in the body.  Methods  This study was a retrospective cohort study. From January 2009 to July 2019, 41 patients with combined burn-blast injuries caused by hot solution explosion who met the inclusion criteria were admitted to the Department of Burns and Plastic Surgery of Qingdao Hospital of Rehabilitation University. The following indexes of all patients were collected, including gender, age, total burn area, admission time after injury, site of combined burn-blast injuries, and type of foreign objects in the body. According to the type of foreign objects in the body, the patients were divided into liquid plastic group (30 cases) and liquid metal group (11 cases). The following indexes of the two groups of patients were collected, including the clinical characteristics (swelling in the injury site, pain, fever, abscess formation, depth of injury, activity of foreign objects, and difficulty in removing foreign objects), imaging examinations (ultrasound, computed radiography, computed tomography, and magnetic resonance imaging examinations), treatment (repair period and repair method), and incidence of complications during follow-up after discharge.  Results  There were 33 males and 8 females among the patients, aged 18-65 years. The total burn area was 1% to 78% total body surface area, the admission time after injury was 2 h to 7 d, the combined burn-blast injuries mainly occurred in the limbs and trunk, and the foreign objects in the body were liquid plastics (polyethylene and acrylonitrile butadiene styrene) and liquid metals (liquid iron and aluminum). The proportions with swelling in the injury site, injury with depth to the bone, poor mobility of foreign objects, and difficulty in removing foreign objects in patients in liquid plastic group were significantly higher than those in liquid metal group (P<0.05). The proportions of confirming foreign objects in the body through computed radiography and computed tomography examinations in patients in liquid metal group were 7/7 and 8/8, respectively, which were significantly higher than 1/5 and 3/20 in liquid plastic group (P<0.05); the proportion of confirming foreign objects in the body through ultrasound examination in patients in liquid metal group was 11/11, which was similar to 24/26 (P>0.05); the proportion of confirming foreign objects in the body through magnetic resonance imaging examination in patients in liquid metal group was 2/2, which was the same as 4/4 in liquid plastic group. The proportions of patients in liquid plastic group who underwent stage Ⅰ wound repair and direct suture were significantly lower than those in liquid metal group (P<0.05), while the proportions of patients who underwent delayed wound repair, skin grafting, and flap grafting were significantly higher than those in liquid metal group (P<0.05). There was no statistically significant difference in the incidence of complications between the two groups of patients during follow-up after discharge (P>0.05).  Conclusions  Combined burn-blast injuries could result in damages of different severity in patients due to different types and locations of foreign objects in the body. Computed radiography and computed tomography examinations can be used to diagnose metal foreign objects in the body, while ultrasound and magnetic resonance imaging examinations can be used to diagnose plastic foreign objects in the body. Multidisciplinary collaboration and comprehensive treatment are important means of treating this type of patients.
Changes in biological characteristics of adipose-derived stem cells in obese patients post successful weight loss
Wei Zhiru, Dong Yan, Qiao Gaihong, Liu Linbo, Li Guangshuai
2024, 40(11): 1066-1074. doi: 10.3760/cma.j.cn501225-20231205-00225
Abstract:
  Objective  To explore the changes in biological characteristics of adipose-derived stem cells (ASCs) in obese patients post successful weight loss, so as to provide a reference for the clinical application of these ASCs in refractory wound repair.  Methods  This study was an experimental study. Twelve obese patients (8 females and 4 males, aged (50±9) years) who underwent abdominal skin tightening surgery after successful weight loss and were admitted to the First Affiliated Hospital of Zhengzhou University from April 2021 to April 2023 were included in weight loss group, and 12 healthy volunteers (10 females and 2 males, aged (50±9) years) who underwent abdominal liposuction and facial fat grafting surgery during the same period in the same institution were included in healthy group. Adipose tissue was collected from patients in weight loss group and volunteers in healthy group, and ASCs were extracted. Experiments were conducted using ASCs at passages 4 and 5. Cell proliferation levels were assessed using the methyl thiazolyl tetrazolium assay at 0 (immediately), 24, 48, and 72 hours of culture. The cell scratch test was performed and the cell migration rates at 12 and 24 hours after scratching were calculated. The cell Transwell assay was performed and the number of migration cells at 24 hours after culture was counted. Adipogenic and osteogenic induction assays were carried out, and the adipogenic and osteogenic differentiation levels of cells were detected after 18 and 21 days of induction, respectively. Real-time fluorescence quantitative reverse transcription polymerase chain reaction was employed to measure the mRNA expressions of lipoprotein lipase (LPL), peroxisome proliferator-activated receptor gamma (PPARγ), Runt-related transcription factor 2 (Runx2), osteopontin, alkaline phosphatase (ALP), matrix metalloproteinase 9 (MMP-9), and transforming growth factor beta (TGF-β). The sample number of each experiment was 12.  Results  At 0 hour of culture, the cell proliferation levels of patients in weight loss group and volunteers in healthy group were 1.022±0.056 and 1.000±0.144, respectively, with no statistically significant difference between the groups (P>0.05). At 24, 48, and 72 hours of culture, the cell proliferation levels of patients in weight loss group were 1.366±0.030, 1.353±0.012, and 1.390±0.016, respectively, which were significantly lower than 1.755±0.077, 1.737±0.014, and 1.700±0.023 of volunteers in healthy group (with t values of 16.27, 71.35, and 38.56, respectively, P values all <0.05). In the cell scratch test, at 12 and 24 hours after scratching, the cell migration rates of patients in weight loss group were lower than those of volunteers in healthy group, but the differences were not statistically significant (P>0.05). In the cell Transwell assay, after 24 hours of culture, there was no statistically significant difference in the number of migrated cells between patients in weight loss group and volunteers in healthy group (P>0.05). After 18 days of adipogenic induction, the cell adipogenic differentiation level of patients in weight loss group was significantly lower than that of volunteers in healthy group (t=27.81, P<0.05). After 21 days of osteogenic induction, the cell osteogenic differentiation level of patients in weight loss group was significantly lower than that of volunteers in healthy group (t=14.85, P<0.05). Compared with those of volunteers in healthy group, the mRNA expressions of LPL, PPARγ, TGF-β, and Runx2 of patients in weight loss group were significantly reduced (with t values of 59.48, 146.10, 46.10, and 3.13, respectively, P<0.05), while there were no statistically significant changes in the mRNA expressions of osteopontin, ALP, or MMP-9 (P>0.05).  Conclusions  Compared with healthy volunteers, the proliferative capacity of ASCs in obese patients after successful weight loss is significantly diminished, the differentiation potential is relatively weak, and the expression levels of some genes corresponding to adipogenic and osteogenic differentiation are decreased, which may affect the therapeutic efficacy of these ASCs in treating refractory wounds caused by burns, diabetes, or radiation injuries. Therefore, the donor differences of ASCs need to be considered in clinical application.
Role and mechanism of human umbilical cord mesenchymal stem cell exosomes in wounds with escharectomy and skin grafting in scalded rats
Wang Di, Dou Shuqian, Wu Kongjia, Zhang Gaofei, Lou Hanxiao, Zhang Chenying, Yang Guoxun, Jin Chengbo, Que Ting, Liu Wenjun
2024, 40(11): 1075-1084. doi: 10.3760/cma.j.cn501225-20231201-00223
Abstract:
  Objective  To investigate the role and mechanism of human umbilical cord mesenchymal stem cell exosomes (hUCMSC-ex) in wounds with escharectomy and skin grafting in scalded rats.  Methods  The study was an experimental study. Twelve male Sprague-Dawley (SD) rats aged 6-8 weeks were divided into combined treatment group, fixed+allogeneic skin group, autologous skin+allogeneic skin group, and allogeneic skin group by random number table method (the same grouping method hereinafter), with 3 rats in each group. The four groups of rats were inflicted with scalded wounds on the back and performed with escharectomy, and then the wounds of rats in combined treatment group were fixed with a metal ring (the same fixing method hereinafter) and transplanted with autologous skin grafts and allogeneic skin grafts, and the other three groups of rats were fixed and/or transplanted with skin grafts corresponding to the group name. At 14, 21, and 28 d after surgery, the wound healing area in the four groups of rats was measured. Another 15 male SD rats aged 6-8 weeks were divided into normal group with no treatment, high exosome group, low exosome group, supernatant group, and phosphate buffer solution (PBS) group, with 3 rats in each group. The last 4 groups of rats were treated as that in the above-mentioned combined treatment group, and then were injected around the wounds with 200 μL of PBS containing 100 μg of hUCMSC-ex, 200 μL of PBS containing 50 μg of hUCMSC-ex, 200 μL of supernatant with no hUCMSC-ex, and 200 μL of PBS at 0 (immediately), 7, 14, and 21 d after surgery, respectively. At 14, 21, and 28 d after surgery, the wound healing area in the four groups of rats was measured. The wound neo-epithelial tissue of rats in high exosome group and PBS group at 28 d after surgery and the normal skin tissue of rats in normal group at the same time point were taken, and the differentially expressed proteins were screened by label-free quantitative proteomics method; the two up-regulated and differentially expressed proteins, the immunoglobulin G1 heavy chain constant region (IGHG1) and cystatin A (CSTA) with the largest and second largest fold changes in comparison between high exosome group and PBS group were selected, and their protein expressions were detected by Western blotting. The number of samples in all experiments was 3.  Results  At 14, 21, and 28 d after surgery, the wound healing area in combined treatment group, autologous skin+allogeneic skin group, and allogeneic skin group of rats was significantly larger than that in fixed+allogeneic skin group (P<0.05), the wound healing area in autologous skin+allogeneic skin group of rats at 21 d after surgery and that in allogeneic skin group of rats at 14 and 21 d after surgery was significantly larger than that in combined treatment group (P<0.05), and the wound healing area in allogeneic skin group of rats at 14 d after surgery was significantly larger than that in autologous skin+allogeneic skin group (P<0.05). The wound healing area of rats in high exosome group and low exosome group at 14, 21, and 28 d after surgery and in supernatant group at 14 and 28 d after surgery was significantly larger than that in PBS group (P<0.05); the wound healing area in high exosome group of rats at 14 and 21 d after surgery was significantly larger than that in supernatant group (P<0.05), and the wound healing area at 14 d after surgery was significantly larger than that in low exosome group (P<0.05); the wound healing area in low exosome group of rats at 14 d after surgery was significantly larger than that in supernatant group (P<0.05). Compared with that in PBS group, 332 proteins were differentially expressed in the neo-epithelial tissue of the wounds in high exosome group of rats at 28 d after surgery (P<0.05), among which the protein expressions of IGHG1 and CSTA were significantly up-regulated (with fold change of 12.60 and 2.27, respectively, P<0.05). Compared with those of normal skin tissue in normal group, 1 400 and 1 057 proteins were differentially expressed in the neo-epithelial tissue of the wounds in high exosome group and PBS group of rats at 28 d after surgery, respectively. The protein expressions of IGHG1 and CSTA in the wound neo-epithelial tissue in high exosome group of rats at 28 d after surgery were significantly larger than those in normal skin tissue of rats in normal group (P<0.05) and those in PBS group (P<0.05).  Conclusions  hUCMSC-ex may accelerate the repair process of wounds with escharectomy and skin grafting and improve the quality of wound healing in scalded rats by regulating the protein expressions of IGHG1 and CSTA.
Effects and mechanism of baicalin on wound healing of full-thickness skin defects in diabetic mice
Shi Yan, Yi Liang, Zhang Weiqiang, Liu Nike, Wen Huicai, Yang Ronghua
2024, 40(11): 1085-1094. doi: 10.3760/cma.j.cn501225-20231104-00179
Abstract:
  Objective  To investigate the effects and mechanism of baicalin on the wound healing of full-thickness skin defects in diabetic mice.  Methods  This study was an experimental research. Mononuclear cells were isolated from five male C57BL/6J mice aged 8-12 weeks and induced to differentiate into macrophages for conducting the subsequent experiments. According to the random number table (the same grouping method below), macrophages in a high-glucose environment were divided into 0 μmol/L baicalin group (no baicalin was added), 5 μmol/L baicalin group, 15 μmol/L baicalin group, 25 μmol/L baicalin group, 50 μmol/L baicalin group, and 75 μmol/L baicalin group treated with the corresponding final molarity of baicalin and 1 μg/mL endotoxin/lipopolysaccharide (LPS). After treatment for 48 hours, the cell proliferation activity was detected using a microplate reader. Macrophages in a high-glucose environment were divided into LPS group treated with 1 μg/mL LPS and LPS+baicalin group treated with 50 μmol/L baicalin+1 μg/mL LPS. After treatment for 48 hours, the percentage of double-positive cells for inducible nitric oxide synthase (iNOS) and CD80, as well as that for arginase 1 (Arg1) and CD206 among the cells, were detected using immunofluorescence method, the secretion levels of interleukin 1β (IL-1β), IL-6, IL-23, IL-10, insulin-like growth factor (IGF), and transforming growth factor β1 (TGF-β1) by the cells were detected using enzyme-linked immunosorbent assay, the expression of reactive oxygen species in the cells was detected using a fluorescent probe method, the protein expression of nuclear factor κB in the cells were detected using Western blotting, and the expression of nuclear factor 2 in the cells was observed using immunofluorescence method. The number of cell experimental samples was 3. Twenty-four 8-week-old male db/db mice were selected. After preparing full-thickness skin defect wounds on their backs, they were divided into baicalin group and normal saline group (with 12 mice in each group). On the third day after injury, 50 μmol/L baicalin and normal saline were injected into the wounds of mice, respectively. The wound healing situation was observed and the percentage of the residual wound area was calculated on the 4th, 8th, and 12th day after injury. The wound tissue was sampled on the 8th day after injury, hematoxylin-eosin staining was performed to observe the epithelial regeneration and inflammatory cell infiltration, the protein expression of CD31 was detected by Western blotting, and the expression of reactive oxygen species was detected by a microplate reader. The number of animal experimental samples was 6.  Results  After treatment for 48 hours, only the proliferation activity of macrophages in 50 μmol/L baicalin group was significantly higher than that in 0 μmol/L baicalin group (P<0.05). After treatment for 48 hours, the percentage of double-positive cells for iNOS and CD80 among the macrophages in LPS+baicalin group was (21.0±2.4)%, which was significantly lower than (66.6±4.5)% in LPS group (t=15.63, P<0.05); the percentage of double-positive cells for Arg1 and CD206 among the macrophages in LPS+baicalin group was (59.1±2.1)%, which was significantly higher than (18.6±1.7)% in LPS group (t=25.38, P<0.05); compared with those in LPS group, the secretion levels of IL-1β, IL-6, and IL-23 by the macrophages in LPS+baicalin group were significantly decreased (with t values of 14.26, 15.95, and 12.23, respectively, P<0.05), while the secretion levels of IL-10, IGF, and TGF-β1 were significantly increased (with t values of 8.49, 11.98, and 13.84, respectively, P<0.05); the expression of reactive oxygen species in the macrophages in LPS+baicalin group was significantly lower than that in LPS group (t=5.54, P<0.05); compared with those in LPS group, the protein expression of nuclear factor κB in the nucleus of the macrophages in LPS+baicalin group was significantly decreased (t=36.22, P<0.05), while that in the cytoplasm was significantly increased (t=14.47, P<0.05), and the expression of nuclear factor 2 in the nucleus was increased. On the 4th and 8th day after injury, the wound area of mice in baicalin group was significantly smaller than that in normal saline group, and the wounds of mice in baicalin group completely healed on the 12th day after injury. On the 4th, 8th, and 12th day after injury, the residual wound area percentage of mice in baicalin group was significantly lower than that in normal saline group (with t values of 13.29, 10.08, and 11.72, respectively, P<0.05). On the 8th day after injury, compared with those in normal saline group, the wound tissue of mice in baicalin group showed significant re-epithelization, the infiltration of inflammatory cells was reduced, the expression of CD31 protein was significantly increased (t=17.23, P<0.05), and the expression of reactive oxygen species was significantly reduced (t=5.78, P<0.05).  Conclusions  Baicalin alleviates the inflammatory response of macrophages by lowering the level of reactive oxygen species in cells and promoting the polarization of macrophages to the M2 type, thereby facilitating the healing of full-thickness skin defect wounds in diabetic mice.
Review
Research advances on animal models of hypertrophic scar
Liu Jiaqi, Han Yige, Li Xueyong, Ma Xianjie
2024, 40(11): 1095-1100. doi: 10.3760/cma.j.cn501225-20231127-00208
Abstract:
A suitable animal model of hypertrophic scar is of great importance for studying pathogenesis of hypertrophic scar and exploring more efficacious treatment. Researchers have tried to establish hypertrophic scar models in various animals, and the rabbit ear hypertrophic scar model is the most widely used one. In recent years, novel models such as the rat tail hypertrophic scar model and ethanol-induced rabbit ear hypertrophic scar model have been proposed. These models inherit the advantages of traditional models while simplifying the manufacturing process, presenting significant research potential. This paper provides the research advances on animal models of hypertrophic scar in nude mice, mice, rats, rabbits, pigs, guinea pigs, and dogs, offering insights for the researchers in selecting appropriate models, refining existing models, or creating new animal models.