血管紧张素(1-7)对压力负荷引起高血压大鼠心肌重构的影响

Effect of angiotensin(1-7) on myocardial remodeling in pressure loaded hypertensive rats

目的观察血管紧张素(1-7)[Ang-(1-7)]对压力负荷增高所致大鼠心肌重构的影响。方法 30只雄性SD大鼠随机分为3组:假手术组、腹主动脉缩窄(AAC)组和Ang-(1-7)组。后2组采用腹主动脉缩窄术建立心脏压力负荷增高动物模型。术后1 d开始,Ang-(1-7)组大鼠经渗透性微量泵持续颈静脉输注Ang(1-7)25μg·kg^(-1)·h^(-1),假手术组及AAC组经渗透性微量泵给予等量生理盐水。4周后鼠尾容积法测量收缩压;称取左心室质量(LVM),计算左心室质量指数(LVMI);HE染色检测心肌细胞平均直径;放免法测定血浆和心肌血管紧张素Ⅱ(AngⅡ)浓度。结果与假手术组相比,AAC组、Ang-(1-7)组收缩压、LVM、LVMI、心肌AngⅡ浓度、心肌细胞平均直径均显著升高(P<0.05,P<0.01)。与AAC组相比,Ang-(1-7)组血压和心肌AngⅡ浓度差异无统计学意义(P>0.05),但LVM、LVMI、心肌细胞平均直径明显降低(均P<0.05)。结论 Ang-(1-7)可改善腹主动脉缩窄高血压大鼠左室肥厚,逆转心肌重构。

Objective To investigate the effect of angiotensin （1-7） on myocardial remodeling which induced by pres- sure overload in rats. Methods Thirty SD rat were randomly divided into 3 groups. Left ventricular hypertrophy was induced by abdominal aortic constriction （AAC） and received angiotensin （ 1-7 ） （25 μg·kg-1·h-1） （ n = 10）. Sham operated rats （ n = 10） and untreated AAC rats （ n = 10） served as controls. Systolic blood pressure （SBP） and LVMI were determined, cardiomyocytes diameter were measured by HE stain; plasma angiotensin II and myocardial angiotensin II levels was detected by radioimmunoassay. Results Compared With sham operation group,SBP, LVMI, mean diameter of cardiomyocytes and myo- cardial angiotensin II concentration in AAC rats were significantly increased （ P 〈 0.05, P 〈 0.01 ）. SBP and myocardial an- giotensin II concentration had no significant differences between AAC rats and Ang （1-7） rats （ P 〉 0.05 ）, While LVMI, mean diameter of cardiomyocytes in Ang （ 1-7 ） rats were Significantly decreased （ all P 〈 0.05 ）. Conclusion Ang （ 1-7 ） could prevent the development of myocardial hypertrophy in pressure overloaded rats and reverse myocardial remodeling.