瘦素预处理经线粒体通路对大鼠心肌缺血再灌注损伤的影响

Effects of leptin pretreatment via mitochondrial pathway on myocardial ischemia reperfusion injury in rats

目的探讨在SD大鼠心肌缺血再灌注损伤(MIRI)中瘦素预处理经线粒体信号通路对机体的影响及相关机制。方法选取健康雄性成年SD大鼠50只,随机分为缺血再灌注(IR)模型对照组(模型组,线栓法制作大鼠IR模型)、假手术组(仅开胸不作血管结扎)、IR瘦素预处理低、中、高剂量(20、50、100μg/kg)共5组,每组10只。各组大鼠经缺血半小时再灌注24 h,观察心肌HE染色病理形态学变化;ELISA法检测血清中白介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)和线粒体通透性转换孔(mPTP)的含量;Western blot法检测凋亡蛋白B淋巴细胞瘤-2基因(Bcl-2)、凋亡相关基因(Bax)的表达。结果与模型组比较,假手术组及瘦素预处理组心肌病理学表现减轻,IL-6、TNF-α、mPTP及Bax表达显著降低(P<0.05),1e:1-2在瘦素预处理组中表达显著增高,且在瘦素高刺量组中表达最高(P<0.05),均无明显剂量依赖性。结论瘦素可缓解MIRI的炎症反应及mPTP的开放,并促进线粒体通路相关蛋白Bcl-2上调,使Bax蛋白的表达下调,从而保护心肌细胞减轻损伤。

Objective To investigate the effect and relevant mechanism of leptin pretreatment via mitochondrial signaling pathway on myocardial ischemia-reperfusion injury in SD rats. Methods 50 healthy male adult SD rats were randomly divided into 5 groups, model group （to make ischemia-reperfusion model by suture method）, sham group（ thoracotomy without vascular ligation）, the low, medium and high dose leptin pretreatment groups （20,50,100 μg/kg, n = 10）. After ischemia for 30 minutes and reperfusion for 24 hours, then to observe the pathological changes of cardiac HE staining in rats ; using ELISA to test serum interleukin-6 （ IL-6）, tumor - stimulating factor- α （TNF-α） and mitochondrial permeability transition pore （mPTP） ;to test the expression of Bcl-2 and Bax apop- totic proteins by Western blot method. Results Compared with the model group, pathological characteristics of sham group and leptin preconditioning groups were improved; IL-6, TNF-α, mPTP and Bax expression was signifi- cantly decreased （P 〈 0.05 ） ; in leptin pretreatment groups, Bcl-2 expression was significantly increased, especial- ly in high dose leptin group （P 〈 0. 05 ）, and there was no obvious dose-dependence. Conclusion Leptin relieve inflammation and inhibite mPTP, up-regulate the expression of Bcl-2 and down - regulate the Bax, thereby protecte cardiomyocytes and mitigate damage on MIRI.