Effects of dexmedetomidine on myocardium of rats with severe burn at early stage
-
摘要: 目的 观察右美托咪定对严重烧伤大鼠早期心肌的作用。 方法 将20只无特殊病原体级雄性SD大鼠浸入90 ℃热水中20 s造成背部30%TBSAⅢ度烫伤(以下称烧伤),按照随机数字表法分为烧伤复苏组10只、烧伤复苏+右美托咪定组10只。2组大鼠伤后一次性腹腔注射乳酸钠林格液2 mL·kg-1·%TBSA-1,其中烧伤复苏+右美托咪定组大鼠同时腹腔注射右美托咪定1 μg/kg。另取5只大鼠设为假伤组,于37 ℃水浴造成假伤,补液条件同烧伤复苏组。2个烧伤组大鼠于伤后6、24 h各取5只大鼠,使用小动物超声成像系统测定左心室收缩末期内径(LVIDs)、左心室舒张末期内径(LVIDd)、射血分数(EF)及心排血量(CO);应用ELISA法检测血浆心肌肌钙蛋白(cTn)I及cTnT水平;分别于光学显微镜、透射电镜(透射电镜仅观察伤后24 h)下观察心肌组织形态变化。假伤组大鼠于伤后24 h进行心肌组织形态学观察,其余检测同前。对数据行单因素方差分析及SNK检验。 结果 伤后6 h,烧伤复苏组大鼠EF值为(98.0±2.8)%,明显高于假伤组[(91.0±0.4)% ,
P <0.05];其余3项心脏超声指标与假伤组相近(P 值均大于0.05)。伤后6 h,烧伤复苏+右美托咪定组大鼠各项心脏超声指标与假伤组相近(P 值均大于0.05)。伤后24 h,烧伤复苏组及烧伤复苏+右美托咪定组大鼠LVIDs水平分别为(0.66±0.59)、(0.69±0.27)mm,明显低于假伤组[(1.65±0.33)mm,P 值均小于0.05];各组大鼠LVIDd、EF及CO水平相近(P 值均大于0.05)。伤后6 h,烧伤复苏组大鼠血浆cTnI、cTnT水平分别为(17.40±1.59)ng/mL、(1 488±229)pg/mL,明显高于假伤组的(1.84±0.92)ng/mL和(169±12)pg/mL (P 值均小于0.01);烧伤复苏+右美托咪定组大鼠血浆cTnI水平[(2.58±0.60)ng/mL]与假伤组接近(P >0.05),血浆cTnT水平[(649±190)pg/mL]明显高于假伤组(P <0.01)。伤后24 h,2个烧伤组大鼠血浆cTnI及cTnT水平与假伤组接近(P 值均大于0.05);烧伤复苏+右美托咪定组大鼠血浆cTnI水平明显低于烧伤复苏组(P <0.01)。伤后6 h,2个烧伤组大鼠心肌结构均较正常,与假伤组伤后24 h相似。伤后24 h,烧伤复苏组大鼠心肌组织明显破坏,肌丝排列较紊乱、线粒体损伤严重,烧伤复苏+右美托咪定组大鼠上述情况较烧伤复苏组显著改善。 结论 右美托咪定对严重烧伤大鼠伤后早期心肌具有一定的保护作用。Abstract: Objective To investigate the effects of dexmedetomidine on myocardium of rats at early stage after severe burn. Methods Twenty specific pathogen free male SD rats were immersed in 90 ℃ hot water for 20 s, causing 30% total body surface area (TBSA) full-thickness scald (hereafter referred to as burn) on the back. And then they were divided into burn resuscitation group (BR) and burn resuscitation+ dexmedetomidine group (BRD) according to the random number table, with 10 rats in each group. Sodium lactate Ringer′s solution (2 mL·kg-1·%TBSA-1) were intraperitoneally injected into rats of both groups after burn. Dexmedetomidine with dose of 1 μg/kg was intraperitoneally injected into rats of group BRD at the same time point. Another 5 rats in sham injury group (SI) were immersed in 37 ℃ water bath causing sham injury, and fluid resuscitation of rats in group SI was the same as that in group BR. Five rats of group BR and BRD were respectively selected at post burn hour (PBH) 6 and 24. And then left ventricular end-systolic internal diameter (LVIDs), left ventricular end-diastolic internal diameter (LVIDd), ejection fraction (EF), and cardiac output (CO) were determined with small animal ultrasonic imaging system. Plasma levels of cardiac troponin (cTn) I and cTnT were detected by enzyme-linked immunosorbent assay, and morphological changes of myocardium were observed under optical microscope and transmission electron microscope (observed only at PBH 24). In rats of group SI, morphological change of myocardium was observed at PBH 24, and the other indexes were detected as above. Data were processed with one-way analysis of variance and SNK test. Results At PBH 6, EF value of rats in group BR [(98.0±2.8) %] was obviously higher than that in group SI [(91.0±0.4)%,P <0.05]. The other 3 cardiac ultrasound indexes of rats in group BR were close to those in group SI (withP values above 0.05). Each cardiac ultrasound index of rats between groups BRD and SI was close at PBH 6 (withP values above 0.05). At PBH 24, LVIDs levels of rats in group BR [(0.66±0.59) mm] and group BRD[(0.69±0.27) mm] were obviously lower than LVIDs level of rats in group SI [(1.65±0.33) mm, withP values below 0.05]. LVIDd, EF, and CO levels of rats were close among 3 groups at PBH 24 (withP values above 0.05). At PBH 6, the plasma levels of cTnI [(17.40±1.59) ng/mL] and cTnT [(1 488±229) pg/mL] of rats in group BR were significantly higher than those in group SI [(1.84±0.92) ng/mL and (169±12) pg/mL, withP values below 0.01]. At PBH 6 in group BRD, the plasma level of cTnI of rats [(2.58±0.60) ng/mL] was close to that in group SI (P >0.05), and the plasma level of cTnT [(649±190) pg/mL] was higher than that in group SI (P <0.01). At PBH 24, the plasma levels of cTnI and cTnT of rats in group SI were close to those in groups BR and BRD (withP values above 0.05). At PBH 24, the plasma level of cTnI of rats in group BRD was obviously lower than that in group BR (P <0.01). At PBH 6, the myocardial structures of rats in group BR and group BRD were normal, which were close to myocardial structure of rats in group SI at PBH 24. At PBH 24, obviously damaged myocardial tissue, disorderly arrangement of myofilament, and seriously damaged mitochondria were observed in rats of group BR, which were significantly ameliorated in rats of group BRD. Conclusions Dexmedetomidine can protect the myocardium of rats with severe burn at early stage.-
Key words:
- Burns /
- Myocardium /
- Dexmedetomidine
点击查看大图
计量
- 文章访问数: 63
- HTML全文浏览量: 6
- PDF下载量: 7
- 被引次数: 0