压力超负荷左室肥厚大鼠心肌组织血管紧张素Ⅱ受体的表达

Expression of caraiomyocyte angiotensin Ⅱ receptors in rat with pressure over load-induced left ventricular hypertrophy

目的:本研究观察压力超负荷左室肥厚(Left ventricular hypertrophy,LVH)大鼠心肌组织AT1和AT2的表达,进一步探讨血管紧张素Ⅱ(AngiotensinⅡ,AngⅡ)受体在左室肥厚中的作用及可能机制。方法:采用腹主动脉缩窄法建立LVH模型,14只Sprague-Dawley(SD)大鼠随机分为:(1)假手术组(n=7);(2)手术组(手术组n=7);用免疫组化法及RT-PCR检测血管紧张素Ⅱ受体(AT)的表达,同时检测LVH的指标:心肌纤维化、左室质量指数(LVMI)、心肌细胞横切面积(CSA)、心肌细胞凋亡指数。结果:与假手术组比较,手术组SBP、DBP、MBP、LVMI、心肌细胞CSA、心肌细胞凋亡指数(Apoptosis index,APOI)、血浆AngⅡ水平及AT1和AT2蛋白和mRNA的表达水平均显著升高。结论:左室肥厚大鼠心肌组织AT1和AT2从蛋白和mRNA表达水平均明显升高;AT1和AT2均参与左室肥厚过程,但二者可能发挥相互拮抗的作用。

Objective：To investigate the role of Ang Ⅱ receptors（AT1 and AT2） in the left ventricular hypertrophic process and its mechanisms through detecting the expression of Ang Ⅱ receptors（AT1 and AT2） in hypertrophic cardiomyocyte induced by pressure overload in rats. Methods：Fourteen Male Sprague-Dawley rats were divided into two groups： sham group（n=7）,and operation group（n=7）. Left ventricular hypertrophy model was well established after abdominal aortic stenosis in each group.The expression of AT1 and AT2 was detected by immunohistochemistry（IHC） and RT-PCR,respectively. Indexes of left ventricular hypertrophy, including myocardial fibrosis, LVMI, cross-sectional area and apoptosis index（APOI）, were also measured. Results： SBP,DBP,MBP,LVMI,and cardiomyocyte CSA,APOI,level of plasma AngⅡ and expression of AT1 and AT2 in operation group were markedly increased as compared with sham group. Conclusion：Expression of cardiomyocyte AT1 and AT2 receptors were increased significantly in rat of left ventricular hypertrophy,which indicated that AT1 and AT2 receptors both participate in the process of left ventricular hypertrophy but they may play antagonism effects.