L-精氨酸增加心肌急性缺血大鼠心脏eNOS基因表达

L-arginine increases the expression of endothelial-type nitric oxide synthase gene in acute myocardial infarction rats

目的 观察大鼠心梗时心脏内皮型一氧化氮合酶 (eNOS)基因表达的变化和L 精氨酸 (L Arg)对大鼠eNOS基因表达的影响。方法 4 8只健康成年SD大鼠随机分为对照组 (假手术组 )、缺血组两组。分别取 1h、2h、2 4h三个不同时间点。采用开胸结扎冠状动脉左前降支的方法建立心肌缺血模型 ,用逆转录聚合酶链式反应 (RT PCR)检测大鼠心梗后不同时间及L 精氨酸 (30mg/ (kg·次 )× 3)给药后缺血心肌eNOSmRNA表达。结果 ①冠脉结扎后 2h组 ,缺血组大鼠心肌eNOSmRNA表达下降 (P <0 0 5 ) ,其下降持续至结扎后 2 4h ;梗死后 2 4h组eNOSmRNA表达与结扎后 2h组相比无显著性差异 ,P >0 0 5 ;②与生理盐水组相比 ,30mg/ (kg·次 )× 3的L Arg静脉注射可增加冠脉结扎后大鼠心肌eNOSmRNA表达 (P <0 0 5 )。结论 ①心梗早期大鼠缺血心肌eNOS基因表达减少 ;②L 精氨酸静脉注射增加心梗大鼠缺血心肌eNOSmRNA表达。

Objectives To observe the expression of endothelial nitric oxide synthase isoforms (eNOS) and the effect of L-arginine on the expression of eNOS after myocardial infarction in rat hearts. Methods forty-eight healthy Sprague-Dawley rats(200～250 g) were randomly divided into two groups ie. controls, ischemia groups. Myocardial ischemia was induced by the left anterior descending coronary artery(LAD) ligation. Animals were sacrificed at 1,2, and 24 h after post-operation. Treatment groups were pretreated with L-Arginine ([L-arg](30 mg/kg·d×3;IP)or saline. The eNOS gene expression in ischemic myocardium was assessed using reverse transcriptase-polymerase chain reaction (RT-PCR) standardized with β-action.Results 1.Ligating of LAD for 2-h decreased significantly the eNOS mRNA levels in ischemic myocardial tissue comparing with that in controls (P<0.05); The decent of eNOS mRNA level sustained for post-operational 24-h; There were no significant difference in expression level between ligating for post-operational 24-h;and between ligating for 2-h groups and ligating for 24-h groups. 2.Injection treatment with L-arginine (30 mg/(kg·d)×3) increased significantly the eNOS mRNA levels in ischemic myocardium cells in rats comparing with that in saline groups (P<0.05).Conclusions 1.The expression of eNOS mRNA in ischemic myocardium cells after myocardial infarction in rats decreases in the early time. 2.L-arg injection via vein can increase significantly the eNOS mRNA production in ischemic myocardium cells in rats after AMI.