氯胺酮对严重烧伤大鼠心肌HSP70表达的影响

Effect of ketamine on the expression of HSP 70 in myocardium in severely burned rats

目的评价氯胺酮对严重烧伤大鼠心肌HSP70表达的影响，探讨其心肌保护的机制。方法雄性Wistar大鼠72只，随机分为正常对照组（C组，n=8）、烧伤组（BI组，n=32）和氯胺酮组（K组，n=32）。K组或BI组于烧伤模型制备成功后15min分别肌肉注射氯胺酮20mg／kg或等容量生理盐水，于给药后3、6、12和24h分别随机处死8只大鼠，取心肌组织，采用Western blot方法检测心肌HSP70的表达，电镜下观察给药后3h时心肌细胞的病理学结果。结果与C组相比，K组和BI组给药后3、6、12及24h时HSP70表达上调（P〈0．05）；与B组相比，K组给药后3、6h时HSP70表达上调（P〈0．05）。K组较BI组给药后3h时心肌病理损伤减轻。结论氯胺酮通过上调心肌HSP70表达，减轻严重烧伤早期大鼠心肌损伤。

Objective To investigate the effect of ketamine on the expression of HSP 70 in myocardium in severely burned rats for its possible mechanism of myocardial protection. Methods Seventy-two male Wistar rats were randomly divided into 3 groups ： normal control group （group C, n = 8）, burn injury group （ group BI , n = 32） and ketamine group （group K, n = 32） . 30% total body surface area of m degree burn model was developed in group BI and group K. Ketamine 20 mg/kg was injected IM in group K 15 min after the burn model was made. Equal volume of normal saline was given instead of ketamine in group BI. Group C received no treatment. The rats were sacrificed at 3, 6, 12 and 24 h after administration in group BI and group K respectively（8 rats at each time point）. Myocardial samples were obtained for determination of the expression of HSP 70 by Western blot analysis. The myocardial ultrastructure was observed at 3 h after administration with electron microscope. Results The myocardial damage was milder in group K than in group BI. The expression of HSP 70 was significantly higher at 3, 6, 12 and 24 h after administration in group K and group BI than in group C（P 〈 0.05）. The HSP 70 expression was significantly higher at 3 and 6 h after administration in group K than in group BI （ P 〈 0.05 ）. Conclusion Ketamine can reduce the myocardial injury induced by severe burn through up-regulating the expression of HSP 70 in cardiocytes.