血管紧张素-(1-7)对心肌肥厚的影响及其与细胞外信号调节激酶的关系

Correlation between the effect of angiotensin-(1-7) on cardiac hypertrophy and extracellular signal-regulated kinase in pressure-overloaded rats

目的:探讨血管紧张素-(1-7)[Ang-(1-7)]对压力负荷性心肌肥厚的影响及其与细胞外信号调节激酶1/2(ERK1/2)的关系。方法:采用腹主动脉缩窄术复制心脏压力负荷增高大鼠模型。75只SD大鼠随机分为假手术组、模型对照组、Ang-(1-7)治疗组。在腹主动脉缩窄术后1d开始,Ang-(1-7)治疗组大鼠,经置入式微量泵持续颈静脉给予Ang-(1-7)(25μg.kg-1.h-1);假手术组及模型对照组经微量泵只给予同量的生理盐水。各组分别于术后1周、术后4周处死部分大鼠,检测左心室重量/体重比、血浆及心肌血管紧张素Ⅱ浓度,并采用免疫印迹方法检测大鼠心肌中磷酸化ERK1/2(p-ERK1/2)表达水平。结果:术后1周和4周,腹主动脉缩窄均导致心肌血管紧张素Ⅱ浓度升高、左心室重量/体重比增加,也导致了心肌中p-ERK1/2表达增高;血管紧张素-(1-7)治疗未改变腹主动脉缩窄对心肌血管紧张素Ⅱ浓度的影响,但能明显减轻腹主动脉缩窄所诱导增高的左心室重量/体重比和心肌中p-ERK1/2表达水平。结论:外源性Ang-(1-7)可减轻压力负荷增高所致的心肌肥厚,这一作用可能与它抑制心肌p-ERK1/2表达有关。

AIM： To investigate the effects and mechanisms of angiotensin - （ 1 - 7） on cardiac hypertrophy in pressure - overloaded rats. METHODS： Ar at model of pressure - overloaded heart was induced by constriction of abdominal aorta. Seventy - five male Sprague Dawley rats were randomized to sham - operated group, model control group and angiotensin - （1 - 7） treatment group. They were treated with intravenous infnsion of angiotensin - （1 - 7） （25 microgram/kg per hour） or saline by minipump. RESULTS： Abdominal aortic banding resulted in a significant increases in LVW/BW, myocardial angiotensin Ⅱ levels, and p - ERK1/2 expression. Angiotensin - （ 1 - 7） had no effect on aortic banding - induced increases in myocardial angiotensin Ⅱ levels, but it significantly attenuated aortic banding- induced increases in LVW/BW and p-ERK1/2 expression. CONCLUSION： Angiotensin - （ 1 - 7） attenuates the development of cardiac hypertrophy in pressure - overloaded rats. It may be associated with the inhibition of p - ERK1/2 expression in cardiac tissue.