短期禁食对大鼠心肌缺血再灌注后心肌酶含量及HSP70表达的影响

Effect of Short-term Fasting on Myocardial Enzymes and HSP70 Expression in Rats after Myocardial Ischemia and Reperfusion

目的观察短期禁食(STF)对大鼠心肌缺血再灌注(I/R)后,其心肌酶含量的变化及热休克蛋白70(HSP70)表达的诱导作用并与心肌缺血预处理(IP)作比较。方法结扎/松解SD大鼠左冠状动脉前降支,建立I/R实验模型。用全自动生化分析仪检测血清肌酸激酶(CK)、肌酸激酶同工酶-MB(CK-MB)和乳酸脱氢酶(LDH)的含量。采用Western blot技术检测各组心肌HSP70含量。结果对照组(即假手术组)上述3种心肌酶含量均少,HSP70极少表达。I/R组3种酶含量均比对照组明显增加,HSP70表达明显。STF+I/R组和IP+I/R组3种酶的增加程度比I/R组明显下降(P<0.05);而HSP70表达明显增强(P<0.05),但两组间无显著性差异。STF+IP+I/R组比上述两组3种酶的增加程度更低(P<0.05),而HSP70过度表达(P<0.01)。结论STF可明显降低I/R所致心肌酶增加,增强HSP70的表达,类似IP的效果,二者联合应用效果更好。

Objective To observe the effect of short-term fasting on myocardial enzymes （creatine phosphor kinase, CK; creatine phosphor kinase isoenzyme, CK-MB; lactate dehydrogenase, LDH ） and the expression of heat shock protein 70 （HSP70） in rats after myocardial ischemia reperfusion （I/R）. Methods The I/R model of SD rat was established by ligating the left anterior descending branch of coronary artery. Forty rats were randomly divided into 5 groups： sham group, ischemia reperfusion group （I/R）, short-term fasting and I/R group （STF＋I/R）, ischemic preconditioning and I/R group （IP＋I/R）, STF＋IP＋I/R group. Western blot was used to evaluate the level of HSP70 expression in myocardium. Serum myocardial enzymes were measured by full automatic biochemical analyzer. Results The contents of CK, CK-MB and LDH in serum and the expression of HSP70 increased significantly in I/R group compared with sham control （P〈0.05）. The contents of myocardial enzymes in serum of STF＋I/R and IP＋I/R were lower than those in I/R group （P〈0.05）, but HSP70 expression increased （P〈0.05） and no significant difference was found between STF＋I/R and IP＋I/R （P〉0.05）. Compared with group STF＋I/R and IP＋I/R, there was a significantly difference for the contents of myocardial enzymes and HSP70 expression in STF＋IP＋I/R group （P〈0.05 or P〈0.01）. Conclusion Short-term fasting or ischemic preconditioning can attenuate the increase of the contents of myocardial enzymes in the serum induced by I/R and upregnlate the HSP70 expression, the combination of STF and IP is more effective against myocardial I/R injury.