血管紧张素Ⅱ对培养的心肌细胞中ACE2表达的影响

Effects of exogenous Angiotensin II on ACE2 expression in cultured cardiomyocytes

目的探讨血管紧张素II(Ang II)对培养的心肌细胞血管紧张素转换酶2(ACE2)基因和其蛋白表达的影响。方法体外原代培养新生SD大鼠的心肌细胞,随机分为对照组和Ang II刺激组。测量心肌细胞的直径和表面积。用RT-PCR法检测心肌细胞中ACE2 mRNA的表达,Western blot检测心肌细胞中ACE2蛋白的表达。结果与对照组相比,用10-7mol/L的Ang II处理,可引起心肌细胞的直径和表面积增加(P<0.01),10-7mol/L Ang II刺激组ACE2 mRNA和其蛋白的表达显著降低(P<0.01)。结论外源性给予10-7mol/L的Ang II,可直接导致心肌细胞肥大,且Ang II刺激引起的心肌细胞中ACE2 mRNA和其蛋白表达的下调,其意义在于使对心肌细胞具有保护作用的Ang(1-7)产生减少,并协同参与了心肌细胞肥大的过程。

AIM To explore the effects of exogenous Angiotensin Ⅱ on ACE2 gene and its protein expression in cultured cardiomyocytes. METHODS Cardiomyocytes of neonatal SD rats were primarily cultured in vitro. The cardiomyocytes were randomly divided into control group and Ang Ⅱ stimulation group. After pretreatment, the cellular surface area and the diameter were measured. RT-PCR and West- ern blot were used to detect the expression of ACE2 mRNA and its protein in cultured cardiomyocytes. RESULTS 10^-7mol/L AngⅡ alone caused obvious increases in the diameter and the cell surface area of cardiomyocytes（P 〈 0.01 ）. Ang II down-regulated ACE2 mRNA and its protein expression （P 〈 0. 01 ）. CONCLUSION Exogenous Ang Ⅱ directly causes cardiomyocyte hypertrophy. AngⅡ downregulates ACE2 mRNA and its protein expression, as well as Ang （ 1 - 7） production, and cooperatively participates in the process of cardiomyocyte hypertrophy.