线粒体通透性转换孔在慢性心力衰竭中的作用及n-3PUFA的保护机制

The role of mitochondrial permeability transition pore in chronic heart failure rats and potential protective effects of n-3 polyunsaturated fatty acid

关键词:  线粒体通透性转换孔  慢性心力衰竭  n-3多不饱和脂肪酸  Caspase-3蛋白  大鼠

Key words:  MPTP  chronic heart failure  n-3 polyunsaturated fatty acid  Caspase-3  rat

摘要:

目的 观察线粒体通透性转换孔(mitochondrial permeablity transition pore, MPTP)在慢性心力衰竭模型中的作用,并初步探讨n-3PUFA的干预作用及其可能机制。方法 采用阿霉素腹腔注射Wistar大鼠建立心力衰竭模型。正常对照组10只,青年和老年心力衰竭组各20只(安慰剂组和n-3PUFA组各10只)。进行超声心动图心功能检测和心肌病理组织学检查；ELISA法检测各组大鼠血清中BNP的表达；提取心肌线粒体,检测膜电位和MPTP孔活性；TUNEL法检测心肌细胞凋亡指数；免疫组化法检测各组大鼠左心室心肌细胞Cleaved-Caspase3的表达。结果 n-3PUFA治疗组与安慰剂组相比,各项心功能指标均明显改善,LVEDD和LVESD明显降低,LVEF及LVFS明显升高(P<0.05),而且心肌损害明显减轻,血清BNP明显降低(P<0.05)。心力衰竭组与对照组相比,心肌线粒体膜电位降低,MPTP孔活性增加,通透性增强,心肌细胞凋亡指数增加,心肌Cleaved-Caspase3蛋白表达升高(P<0.05)。n-3PUFA治疗组与安慰剂组相比,心肌线粒体膜电位增加,MPTP孔活性降低,通透性降低,心肌细胞凋亡指数降低,心肌Cleaved-Caspase3表达下调(P<0.05)。结论 n-3PUFA可能通过抑制心肌线粒体MPTP孔活性,抑制心肌细胞凋亡,有效改善年心力衰竭模型的心功能。

Abstract:

ObjectiveTo investigate the role of mitochondrial permeability transition pore in chronic heart failure rats and potential protective effects of n-3 polyunsaturated fatty acid. Methods Thirty Wistar rats were divided into 3groups: the control group(n=10); heart failure(HF)+placebo group(n=10); heart failure(HF)+n-3PUFA group(n=10). HF groups received intraperitoneal injection of doxorubicin 2mg/kg every week. The n-3PUFA group was treated with n-3PUFA by gavage daily for 8 weeks. Echocardiography and histological examination were performed in 3 groups. The concentration of BNP in the serum was measured by ELISA. The mitochondrial membrane potential and MPTP activity were measured by relevant kits. Apoptotic index (AI) was detected by TUNEL assay. The expression of Cleaved-Caspase3 was evaluated by immunohistochemistry. Results Compared with the HF placebo group, the echocardiography parameters and histological damage of n-3PUFA group were attenuated. Compared with the control group, BNP in the serum of HF group were elevated(P<0.05). The mitochondrial membrane potential in the HF+placebo group was significantly lower than the control groups, while the MPTP activity was significantly elevated(P<0.05).Compared with the HF+placebo group, the mitochondrial membrane potential was significantly increased, the MPTP activity was significantly decreased, the apoptotic index and the expression of Cleaved-Caspase3 were significantly reduced in N-3 PUFA group(all P<0.05). Conclusion n-3PUFA can decrease the MPTP activity, inhibit the myocardial apoptosis in chronic heart failure rats, which might be the potential mechanism of protective effects.