苦参素对心肌缺血再灌注损伤大鼠氧化应激和细胞凋亡的影响

摘要

目的：研究苦参素对心肌缺血再灌注损伤大鼠氧化应激和心肌细胞凋亡的影响。方法将120只雄性SD大鼠随机分为假手术组，模型组，苦参素低（25 mg／kg ）、中（50 mg／kg）、高（100 mg／kg）剂量组和地尔硫卓（1 mg／kg）组；除假手术组外，其余各组大鼠均通过夹闭冠状动脉30 min后松夹的方法制备心肌缺血再灌注损伤模型；再灌注后各给药组立即通过腹腔注射给药，每天1次，连续7 d，假手术组和模型组给予等体积生理盐水。末次给药后，生化分析法测定血清谷草转氨酶（AST）、磷酸肌酸激酶（CPK）、乳酸脱氢酶（LDH）水平；通过TTC染色法测定心肌梗死面积，通过苏木精－尹红（ HE）染色观察心肌组织病理形态学改变；测定心肌组织中超氧化物歧化酶（ SOD）、谷胱甘肽过氧化物酶（ GSH－Px）活性，总抗氧化能力（T－AOC）水平以及丙二醛（MDA）含量；通过原位细胞凋亡检测（TUNEL）法观察心肌细胞凋亡状况并计算凋亡指数；通过免疫组织化学（ IHC）法检测心肌组织中bcl－2、bax蛋白表达情况并进行半定量分析，计算bcl－2／bax比值。结果苦参素中、高剂量组大鼠血清AST、CPK、LDH水平明显低于模型组（P均＜0．05），心肌梗死面积明显小于模型组（P均＜0．05）；心肌组织中SOD活性显著高于模型组（P均＜0．05）， MDA含量显著低于模型组（P均＜0.05），其中苦参素高剂量组GSH－Px活性和T－AOC水平均显著高于模型组（P均＜0．05）。各给药组大鼠心肌组织病变不同程度改善，其中以苦参素高剂量组效果最为显著；各给药组大鼠心肌细胞凋亡状况明显好转，苦参素中、高剂量组凋亡指数明显低于模型组（ P均＜0．05）；苦参素中、高剂量组大鼠心肌组织中bcl－2表达量和bcl－2／bax比值明显高于模型组（P均＜0．05），bax表达量明显低于模型组（P均＜0．05）。结论苦参素对心肌缺血再灌注损伤大鼠氧化应激损伤和心肌细胞凋亡具有抑制作用；作用机制可能与其能够改善抗氧化酶活性、促进抑制凋亡蛋白bcl－2表达、抑制促凋亡蛋白bax表达并提高bcl－2／bax比值有关。%Objective It is to investigate the effects of oxymatrine( OMT) on oxidative stress and myocardial apoptosis in rats with myocardial ischemia-reperfusion injury.Methods 120 rats were randomly divided into six groups: sham operation group, model control group, OMT(25, 50, 100 mg/kg) treated groups and diltiazem (1 mg/kg) treated group ( positive con-trol group);except the rats in sham operation group, the rat models were made by clamping the artery for 30 min, and the drugs were given after reperfusion immediately, once a day for 7 days.Seven days later, the areas of myocardial infarction were analyzed by TTC staining, the histopathological changes was observed by HE staining;the content of AST, CPK, LDH in serum were determined;the activity of SOD, GSH-Px, T-AOC and the content of MDA in myocardial tissue were deter-mined.The apoptosis of cardiomyocytes was observed by TUNEL and the apoptosis index was calculated;the expression of bcl-2, bax were detected by IHC and were Semi-quantitative analyzed, and the ratio of bcl-2/bax was calculated.Results Com-pared with the model control group, the areas of myocardial infarction of OMT 50, 100 mg/kg treated groups were significantly decreased( P all<0.05);the histopathological changes were significantly improved, especially in the OMT 100 mg/kg treated group;the content of AST, CPK, LDH in serum of OMT 50, 100 mg/kg treated groups were significantly decreased(P all<0.05);the activity of SOD in myocardial tissue was significantly increased and the content of MDA significantly was decreased ( P all<0.05) , the activity of GSH-Px and the level of T-AOC in OMT 100 mg/kg treated group were significantly in-creased(P<0.05).The cardiomyocytes apoptosis of OMT treated groups were significantly improved, and the apoptosis index of OMT 50, 100 mg/kg treated groups were significantly decreased(P all<0.05);the expression of bcl-2 was significantly up-regulated, the expression of bax was significantly down-regulated, and the ratio of bcl-2/bax in OMT 50, 100 mg/kg trea-ted groups were significantly increased(P all<0.05).Conclusion OMT had inhibition effects on oxidative stress and myocar-dial apoptosis in rats with myocardial ischemia-reperfusion injury, which perhaps related to its effects of enhancing the activity of antioxidant enzymes, up-regulating the expression of bcl-2 and down-regulating the expression of bax, enhancing the ratio of bcl-2/bax.