N(2)-L-丙氨酰-L-谷氨酰胺对肾缺血再灌注心肌细胞凋亡及相关因子表达的影响

The protective effect and possible mechanism of N-acetysteine on myocardial injury in renal ischemia-reperfusion rats

目的探讨N(2)-L-丙氨酰-L-谷氨酰胺(LAG)对肾缺血再灌注致心肌细胞凋亡及相关因子表达的影响。方法清洁级Wistar大鼠30只,体重250~300 g,随机分为3组(n=10):假手术组(sham组)、肾缺血再灌注组(I/R组)和LAG处理组(LAG+I/R组)。Sham组仅切除右肾,游离左肾动脉,关腹。LAG+I/R组和I/R组切除右肾,夹闭左肾动脉45min再灌注以制备肾缺血再灌注模型,分别于夹闭动脉前30min给予LAG150mg/kg和等量生理盐水。三组均于再灌注6h处死大鼠,取心肌组织,HE染色观察病理组织学变化,Masson染色观察心肌细胞变化;ELISA检测血浆中丙二醛(MDA)含量及超氧化物歧化酶(SOD)活性;Western-blot法检测Bcl-2、Bax、Caspase-3蛋白表达水平。结果 N(2)-L-丙氨酰-L-谷氨酰胺能够减轻肾缺血再灌注致心肌细胞损伤,可降低MDA表达水平,升高SOD表达(P<0.05),抑制心肌中Bax和Caspase-3蛋白表达(P<0.05)。结论肾缺血再灌注可导致心肌细胞凋亡,造成一定的心肌损伤,LAG对肾缺血再灌注心脏损伤的保护作用可能与升高SOD和Bcl-2表达,降低MDA、Bax和Caspase-3表达相关。

Objective To investigate the protective effect and possible mechanism of N-acetysteine on myocardial injury in renal ischemia-reperfusion Wistar rats. Method Thirty clean Wistar rats,weighing 250-300 g,were randomly divided into 3 groups（n=10 each）：sham operation group（sham）,ischemia-reperfusion group（I/R） and N-acetysteine treatment group（LAG＋ I/R）. IR rats were induced by left renal artery occlusion for 45 minutesin, 150mg/kg N-acetysteine and the same volume of saline were infused respectively 30 min before clip the artery in these two groups. The rats were executed after 6h of reperfusion, myocardial tissues were stained by HE. Enzyme-linked immunosorbent assay was conducted to detect malondialdehyde（MDA） and superoxide dismutase（SOD） activity. Bcl-2、Bax、Caspase-3 protein expressions were detected by immunohistochemical and Western-blot methods. Results N（2）-L--L-glutamine relieved the myocardial injury induced by renal ischemia and reperfusion, decreased the expression level of MDA, increased the expression level of SOD（P〈0.05）, and inhibitd the expression levels of Bax and Caspase-3 in myocardium（P〈0.05）. Conclusion The protective effect of N-acetysteine pretreatment on myocardial injury might be related to increase of Bcl-2 gene expression and decrease of Bax and Caspase-3 gene expression in myocardium of I/R rats.