血管紧张素Ⅳ促新生大鼠心肌细胞生长的实验研究

目的： 研究血管紧张素Ⅳ（Ang Ⅳ）对心肌细胞生长的影响及特点。 方法： 体外培养新生大鼠心肌细胞，将培养的心肌细胞分为对照组、不同浓度和不同干预时间组。分别用改良的Bradford法、流式细胞仪检测Ang Ⅳ对新生大鼠心肌细胞的蛋白表达及细胞周期的影响。 结果： Ang Ⅳ使心肌细胞的蛋白量明显大于对照组（P<0.05），并且存在着时间依赖性(36、48 h时，P<0.01)；而且，不同浓度的Ang Ⅳ均加速心肌细胞由静止期、 DNA合成前期向DNA合成期的转换，使DNA合成期及DNA合成后期的细胞数增加，促进心肌细胞的生长；且10-6mol/L的AngⅣ比10-5mol/L的AngⅣ使更多的细胞从G1期向S期转化。 结论： AngⅣ可能是通过AT4介导，对新生大鼠心肌细胞具有直接促蛋白合成及促进心肌细胞生长，并各自存在着时间及浓度依赖性。

Effects of angiotensin Ⅳ on growth of cultured neonatal rat cardiomyocytes

AIM: To study the effects of angiotensin Ⅳ (Ang Ⅳ) on growth of cultured neonatal rat cardiomyocytes. METHODS: Cardiomyocytes isolated from neonatal SD rat were cultured in vitro and divided into groups: control DMEM, 10-6 mol/L Ang Ⅳ, 10-5 mol/L Ang Ⅳ. The effects of Ang Ⅳ were assayed as follows: protein synthesis was determined by modified Bradford method, and cell cycle by flow cytometry. RESULTS: Ang Ⅳ promoted protein synthesis (P<0.05), when cardiomyocytes were incubated for 36 h and 48 h, Ang Ⅳ promoted protein synthesis more evidently (P<0.01). Ang Ⅳ accelerated the change of rat cardiomyocytes from G0/G1 to S phases and increased the numbers of cells of S and G2/M phases. Besides, 10-6 mol/L AngⅣ accelerated the change of that from G0/G1 to S phases more evidently. CONCLUSION: Ang Ⅳ directly increases protein synthesis in cardiomyocytes in a time-dependent manner. Ang Ⅳ influences growth of cardiomyocytes in a concentration-dependent fashion.