锌转运体Zip1在糖尿病缺血再灌注大鼠七氟烷后处理心肌保护中的作用

Role of zinc transporter Zip1 in cardioprotection of sevoflurane postconditioning in diabetic rats with ischemia and reperfusion injury

目的探讨糖尿病大鼠心肌缺血再灌注时锌转运体Zip1的表达变化与七氟烷后处理心肌保护作用的关系。方法采用随机数字表法将SD大鼠分为4组:心肌缺血再灌注(I/R)组、七氟烷后处理组(I/R+SEV组)、糖尿病心肌缺血再灌注组(DM+I/R组)、糖尿病七氟烷后处理组(DM+I/R+SEV组),每组15只。4组大鼠均采用缺血30 min再灌注120 min建立心肌缺血再灌注损伤模型。DM+I/R组和DM+I/R+SEV组采用高脂高糖饮食8周后腹腔注射35 mg/kg STZ建立糖尿病模型,然后再进行心肌缺血再灌注损伤。I/R+SEV组和DM+I/R+SEV组于再灌注开始前1 min,通过挥发罐持续吸入2.5%七氟烷10 min。采用ELISA法检测血清肌钙蛋白I(cTnI)浓度;然后处死大鼠取心脏,TTC染色法检测心肌梗死范围,免疫组化法检测心肌Zip1蛋白表达,蛋白免疫印迹法检测心肌Zip1、Drp1、PINK1、Parkin的表达水平。结果与I/R组比较,I/R+SEV组血清cTnI含量和心肌梗死体积百分比降低(P<0.05),Zip1表达差异无统计学意义(P>0.05),Drp1、PINK1、Parkin蛋白表达降低(P<0.05);与I/R组比较,DM+I/R组血清cTnI含量和心肌梗死体积百分比升高(P<0.05),Zip1表达显著降低(P<0.01),Drp1表达升高(P<0.05),PINK1、Parkin表达显著降低(P<0.01)。与I/R+SEV组比较,DM+I/R+SEV组血清cTnI含量和心肌梗死体积百分比升高(P<0.05),Zip1表达显著降低(P<0.01),Drp1表达显著升高(P<0.01),PINK1、Parkin表达降低(P<0.05)。与DM+I/R组相比,DM+I/R+SEV组上述指标差异均无统计学意义(P>0.05)。结论糖尿病大鼠七氟烷后处理心肌保护效应的消失可能与糖尿病大鼠心肌Zip1表达下调有关。

Objective To explore the correlation between alterations in the expression of the zinc transporter Zip1 during myocardial ischemia-reperfusion in diabetic rats and the cardioprotective effects of sevoflurane postconditioning.Methods Using a random number table,Sprague-Dawley rats were assigned into four groups:myocardial ischemia-reperfusion group(I/R),sevoflurane postconditioning group(I/R+SEV),diabetic myocardial ischemia-reperfusion group(DM+I/R),and diabetic sevoflurane postconditioning group(DM+I/R+SEV),with 15 rats in each group.The myocardial ischemia-reperfusion injury model was simulated by 30 min ischemia and 120 min reperfusion.The rats were intraperitoneally injected with STZ at a dosage of 35 mg/kg after feeding a high-fat,high-sugar diet for eight weeks,and then given 30 min ischemia and 120 min reperfusion in DM+I/R group and DM+I/R+SEV group.The rats in I/R+SEV group and DM+I/R+SEV group inhaled 2.5%sevoflurane for 10 min via vaporizer from one minute prior to reperfusion.Serum cardiac troponin I(cTnI)concentration was determined using ELISA.Then the rats were executed to collect hearts.Myocardial infarction area was assessed by TTC staining,and Zip1 protein expression was evaluated by immunohistochemistry.Additionally,the expression levels of myocardial Zip1,Drp1,PINK1,and Parkin proteins were detected by Western blotting.Results Compared to I/R group,serum cTnI level and myocardial infarction volume percentage were decreased(P<0.05),Zip1 expression showed no significant change(P>0.05),and the expressions of Drp1,PINK1,and Parkin proteins were reduced(P<0.05).Compared to I/R group,serum cTnI level and myocardial infarction volume percentage were increased in DM+I/R group(P<0.05),Zip1 expression was reduced(P<0.01),Drp1 expression was elevated(P<0.05),and PINK1 and Parkin expressions were significantly decreased(P<0.01).Compared with I/R+SEV group,serum cTnI level and myocardial infarction volume percentage were increased in DM+I/R+SEV group(P<0.05),Zip1 expression was decreased(P<0.01),Drp1 expression was significantly increased(P<0.01),and PINK1 and Parkin expressions were reduced(P<0.05).There were no statistically significant differences in the above indexes between DM+I/R group and DM+I/R+SEV group(P>0.05).Conclusion The loss of cardioprotective effects after sevoflurane postconditioning in diabetic rats may be associated with the downregulation of myocardial Zip1 expression.