迷走神经刺激对肝缺血再灌注大鼠心肌损伤时PINK1/Parkin信号通路的影响

Effect of vagus nerve stimulation on PINK1/Parkin signaling pathway during myocardial injury induced by hepatic ischemia-reperfusion in rats

目的:评价迷走神经刺激对肝缺血再灌注大鼠心肌损伤时同源性磷酸酶张力蛋白诱导激酶1(PINK1)/帕金蛋白(Parkin)信号通路的影响。方法:清洁级健康雄性SD大鼠27只,10~12周龄,体质量280~320 g。采用随机数字表法分为3组(n=9):假手术组(Sham组)、肝缺血再灌注组(HI/R组)和迷走神经刺激组(VNS组)。采用夹闭肝蒂缺血1 h,恢复灌注6 h的方法制备大鼠肝缺血再灌注损伤模型。VNS组于肝缺血即刻行迷走神经刺激,持续1 h,刺激频率20 Hz,波宽0.1 ms,刺激电压随大鼠心率变化调整,维持心率较基础值下降10%。于再灌注6 h时麻醉大鼠后取颈动脉血样,采用ELISA法检测血清心肌肌钙蛋白I(cTnI)浓度,随后处死大鼠取左心室心肌组织,采用TUNEL法观察心肌细胞凋亡情况,Western blot法检测PINK1、Parkin、p62、Bax和Bcl-2的表达。结果:与Sham组比较,HI/R组和VNS组血清cTnI浓度和心肌细胞凋亡率升高,心肌PINK1、Parkin和Bcl-2表达下调,p62和Bax表达上调(P<0.05);与HI/R组比较,VNS组血清cTnI浓度和心肌细胞凋亡率降低,心肌PINK1、Parkin和Bcl-2表达上调,p62和Bax表达下调(P<0.05)。结论:迷走神经刺激减轻肝缺血再灌注致大鼠心肌损伤的机制与激活PINK1/Parkin信号通路有关。

ObjectiveTo evaluate the effect of vagus nerve stimulation on the homologous phosphatase and tensin homologue(PTEN)-induced putative kinase 1(PINK1)/Parkin signaling pathway on myocardial injury induced by hepatic ischemia-reperfusion(I/R)in rats.MethodsTwenty-seven clean-grade healthy male Sprague-Dawley rats,aged 10-12 weeks,weighing 280-320 g,were divided into 3 groups(n=9 each)using a random number table method:sham operation group(Sham group),hepatic I/R group(HI/R group)and vagus nerve stimulation group(VNS group).The liver I/R injury model was made by clamping the liver pedicle for 1 h followed by 6-h reperfusion.In VNS group,the left cervical vagus nerve was stimulated by a voltage with a frequency of 20 Hz and a wave width of 0.1 ms immediately after liver ischemia,lasting for 1 h.The stimulation voltage was adjusted with the rat heart rate,and the heart rate decreased by more than 10%of the basic value was considered as a successful stimulation.The rats were anesthetized at the end of reperfusion,and carotid blood samples were collected for determination of the serum cardiac troponin I(cTnI)concentration by enzyme-linked immunosorbent assay.Then rats were sacrificed,and left ventricular myocardial tissues were taken for determination of the apoptosis in cardiomyocytes(by TUNEL)and expression of PINK1,Parkin,p62,Bax and Bcl-2(by Western blot).The apoptosis rate was calculated.ResultsCompared with Sham group,the concentrations of serum cTnI and apoptotic rate of cardiomyocytes were significantly increased,the expression of PINK1,Parkin and Bcl-2 in myocardial tissues was down-regulated,and the expression of p62 and Bax was up-regulated in HI/R group and VNS group(P<0.05).Compared with HI/R group,the concentrations of serum cTnI and apoptotic rate of cardiomyocytes were significantly decreased,the expression of PINK1,Parkin and Bcl-2 in myocardial tissues was up-regulated,and the expression of p62 and Bax was down-regulated in VNS group(P<0.05).ConclusionsThe mechanism by which vagus nerve stimulation alleviates myocardial injury induced by hepatic I/R is related to activation of the PINK1/Parkin signaling pathway in rats.