ACE抑制剂对糖尿病大鼠心肌组织GluT4基因与蛋白表达的影响

目的　研究ACE抑制剂对糖尿病大鼠心肌组织GluT4基因与蛋白表达的影响。方法　大鼠随机分对照组、糖尿病组及苯那普利治疗组。观察 4wk后应用荧光分光光度法检测各组血浆和心肌组织ACE活性 ,Northern杂交检测心肌组织GluT 4mRNA表达 ,Western杂交检测心肌组织细胞膜GluT4蛋白表达。结果　与对照组相比 ,糖尿病组血浆ACE活性趋于下降 ,心肌组织内ACE活性却明显升高 (P<0 0 5) ,苯那普利对糖尿病大鼠血浆和心肌组织ACE活性均有明显抑制作用 ,分别达 92 1%和 89 0 %。Northern杂交显示糖尿病大鼠心肌组织GluT4mRNA表达明显下调 ,约比对照组下降 40 % ,苯那普利治疗 4wk对此无明显影响。Western杂交显示糖尿病大鼠心肌组织细胞膜GluT4蛋白表达也明显下调 ,但苯那普利治疗 4wk可使下调的GluT4蛋白表达明显增加 (P <0 0 5)。结论　苯那普利不仅对糖尿病大鼠血浆ACE活性有明显抑制作用 ,对心肌组织ACE活性也能明显抑制 ,它对糖尿病大鼠心肌组织下调的GluT4mRNA表达无明显影响 ,但可使糖尿病大鼠心肌组织细胞膜下调的GluT4蛋白表达明显增加

Effects of ACE inhibitor on the expression of GluT4 mRNA and protein in diabetic rat heart

AIM To study effects of ACE inhibitor on the ex pression of GluT4 mRNA and protein in diabetic rat heart. METHODS The following groups of rats were randomly designed: control rats, diabetic ra ts and diabetic rats treated with benazepril (an ACE inhibitor). After 4 weeks o f treatment, ACE activities were determined by fluorimetric assay in plasma and heart; Myocardial GluT4 mRNA expression were measured by Northern blot analysis; GluT4 protein expression were measured by Western blot analysis. RESULT S After 4 weeks of treatment, there was a significant increase in myocard ial ACE activities despite a trend toward reduce in plasma activitics, ACE activ ities were inhibited by 92 1%, 89 0% in plasma and heart, respectively; Northe rn blot analysis revealed that the expression of GluT4 mRNA was reduced in diabe tic rat heart by 40%, and treatment with benazepril did not prevent the diabetes -induced reduction of GluT4 mRNA; However, Western blot analysis revealed that benazepril did prevent the diabetes-induced reduction of GluT4 protein in cell membrane of diabetic rat heart. CONCLUSION Benazepril could significantly suppress ACE activities in diabetic rat heart, bu t it did not influence the expression of the myocardial GluT4 mRNA. However, it did prevent the diabetes-induced reduction of GluT4 protein in cell membrane of rat heart.