α-亚麻酸减轻糖尿病大鼠心肌缺血/再灌注损伤

Alpha-linolenic acid intake attenuates myocardial ischemia/reperfusion injury in diabetic rats

目的研究摄食α-亚麻酸(ALA)对糖尿病大鼠心肌缺血/再灌注(MI/R)损伤的影响。方法构建高脂饲料-链脲霉素诱导的2型糖尿病大鼠模型(HFD-STZ),每日灌胃给予正常或HFD-STZ大鼠ALA处理(500μg/kg),4周后行心肌缺血(30 min)/再灌注(4或6 h),并检测心肌梗死范围、血清肌酸激酶(CK)、乳酸脱氢酶(LDH)活性、细胞凋亡,用Western blot检测PI3K、Akt等。结果 HFD-STZ大鼠MI/R损伤加重,虽摄食ALA 4周对正常动物MI/R损伤无影响,但可将HFD-STZ大鼠的心梗面积减小至37.7%±5.4%,显著低于对照组的45.6%±8.5%(P<0.05),且血清CK、LDH活性及细胞凋亡减少;还可增加HFD-STZ大鼠心肌PI3K表达及Akt磷酸化。结论长期摄食ALA有效减轻糖尿病大鼠MI/R损伤,可能与激活PI3K-Akt信号有关。

Objective To investigate the effects of Alpha-linolenic acid（ALA） intake on myocardial ischemia/reperfusion（MI/R） injury in diabetic rats.Methods The high-fat diet-fed streptozotocin（HFD-STZ） rat model was developed.Age-mathched normal and HFD-STZ rats were randomly assigned to receive non-ALA diet or ALA（o.g.,500 μg/kg per day）.After 4 wks of feeding animals were subjected to 30 min of myocardial ischemia and 4 or 6 hrs of reperfusion.Results HFD-STZ rats showed more severe myocardial injury.Although ALA intake for 4 wks did not change myocardial injury in normal rats,it significantly reduced infarct size,plasma creatine kinase and lactate dehydrogenase activities,and apoptosis in HFD-STZ diabetic rats.Moreover,myocardial PI3K expression and Akt phosphorylation were increased by ALA intake in diabetic but not normal rats.Conclusions Chronic ALA intake confers cardioprotection in MI/R in diabetic but not normal rats,which is possibly mediated through PI3K-Akt-dependent mechanism.