Analysis of differential gene expressions of inflammatory and repair-related factors in chronic refractory wounds in clinic

Objective To compare the tissue morphology and gene expressions of inflammatory and repair-related factors in chronic refractory wound tissue including pressure ulcers and diabetic feet. Methods During August 2016 to September 2017, 10 samples of prepuce were collected after circumcision of 10 urological patients [all male, aged (38±4) years old] admitted in the First Affiliated Hospital of Nanchang University and included in normal skin group, samples of tissue around the edge of wounds with blood supply were collected from 9 heat or electric burn patients [6 male patients, 3 female patients, aged (51±8) years old], 13 pressure ulcer patients [9 male patients, 4 female patients, aged (51±14) years old] and 10 diabetic foot patients [8 male patients, 2 female patients, aged (61±10) years old] during the operations. The samples were divided into burn wound group (9 samples), pressure ulcer group (13 samples), and diabetic foot group (10 samples). Ten slices were taken from pressure ulcer group and diabetic foot group respectively, and 5 slices in each group were used to observe the tissue morphology and expressions of Ki67 and CD31 of wounds respectively with immunofluorescence method. Ten samples from normal skin group, 9 samples from burn wound group, 13 samples from pressure ulcer group, and 10 samples from diabetic foot group were collected for analysis of mRNA expressions of vascular endothelial growth factor 192 (VEGF192), transforming growth factor β (TGF-β), vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) , interleukin-1β (IL-1β), IL-6, and tumor necrosis factor α (TNF-α) by real time fluorescent quantitative reverse transcription polymerase chain reaction. Data were processed with Mann-Whitney U test and Kruskal-Wallis rank-sum test. Results (1) The expression level of Ki67 in diabetic foot group (390±100) was higher than that of pressure ulcer group (182±14, Z=-2.611, P<0.01). (2) Although there were a large number of vascular endothelial cells (CD31 positive cells) in wounds of diabetic foot group, their distribution was disordered and failed to form intact lumen. There were less vascular endothelial cells in wounds of pressure ulcer group than those of diabetic foot group, but the complete lumen was formed. (3) The mRNA expression levels of VEGF192 in wounds of burn wound group, pressure ulcer group, and diabetic foot group were significantly lower than the level in normal skin group (H=13.72, 30.50, 15.20, P<0.05 or P<0.01), and the level was the lowest in pressure ulcer group. The mRNA expression level of VEGF192 in wounds of pressure ulcer group was significantly lower than that of diabetic foot group (H=15.30, P<0.01). Compared with that of normal skin group, the mRNA expression level of TGF-β in wounds of burn wound group showed no significant difference (H=-9.50, P>0.05), while the mRNA expression levels of TGF-β in wounds of pressure ulcer group and diabetic foot group were significantly decreased (H=18.04, 14.50, P<0.01). The mRNA expression level of TGF-β in wounds of pressure ulcer group was similar to that of diabetic foot group (H=3.54, P>0.05). (4) Compared with those of normal skin group, the mRNA expression levels of VCAM-1 in wounds of burn wound group and pressure ulcer group were significantly increased (H=-22.50, -11.50, P<0.05 or P<0.01), and there was no significant difference in the mRNA expression level of VCAM-1 in wounds of diabetic foot group (H=10.00, P>0.05); the mRNA expression level of ICAM-1 in wounds of burn wound group showed no significant difference (H=-9.50, P>0.05), and the levels of ICAM-1 in wounds of pressure ulcer group and diabetic foot group were significantly decreased (H=16.50, 16.50, P<0.01). The mRNA expression level of VCAM-1 in wounds of pressure ulcer group was significantly higher than that of diabetic foot group (H=-21.50, P<0.01), the mRNA expression level of ICAM-1 in wounds of pressure ulcer group was similar to that of diabetic foot group (H=0, P>0.05). (5) Compared with those of normal skin group, except for the mRNA expression level of IL-1β in wounds of diabetic foot group showed no significant difference (H=-10.00, P>0.05), the mRNA expression levels of IL-1β in wounds of burn wound group and pressure ulcer group were significantly increased (H=-32.50, -21.50, P<0.01); the mRNA expression levels of IL-6 were significantly increased in wounds of burn wound group, pressure ulcer group, and diabetic foot group (H=-17.50, -30.50, -11.80, P<0.05 or P<0.01); except for the mRNA expression level of TNF-α in wounds of burn wound group showed no significant difference (H=-9.50, P>0.05), the mRNA expression levels of TNF-α in wounds of pressure ulcer group and diabetic foot group were significantly decreased (H=18.04, 14.50, P<0.01). The mRNA expression levels of IL-1β and TNF-α in wounds of pressure ulcer group were significantly lower than those of burn wound group (H=11.00, 27.54, P<0.05 or P<0.01), while the mRNA expression level of IL-6 was significantly higher (H=-13.00, P<0.05). The mRNA expression levels of IL-1β and TNF-α in wounds of diabetic foot group were significantly lower than those of burn wound group (H=22.50, 24.00, P<0.01), while the mRNA expression level of IL-6 showed no significant difference (H=5.70, P>0.05). Conclusions The phenotypes of diabetic foot and pressure ulcer vary from the expressions levels of proliferating cell nuclear antigen and blood vessels forming ability to the expression levels of growth factors, cell adhesion factors, and inflammatory cytokines.