丹参酮ⅡA磺酸钠对AngⅡ诱导的心肌细胞肥大反应中磷酸化细胞外信号调节激酶1/2的作用

目的从细胞外信号调节激酶1/2(ERK1/2)激活角度研究丹参酮ⅡA磺酸钠(sodium tanshinoneⅡ Asulfonate,STS)对血管紧张素Ⅱ(angiotensinⅡ,AngⅡ)诱导的心肌肥大反应中的作用。方法培养新生大鼠心肌细胞,考马斯亮蓝法测定心肌细胞蛋白含量、[3H]-亮氨酸参入法测定蛋白合成速率作为心肌肥大指标;用免疫荧光标记法和Western blot测定磷酸化ERK1/2蛋白(p-ERK1/2)表达。结果(1)AngⅡ(1μmol·L-1)处理24h,心肌细胞[3H]-亮氨酸参入率、蛋白含量明显增加,STS能明显抑制AngⅡ介导心肌细胞[3H]-亮氨酸参入率、蛋白含量的增加;(2)AngⅡ刺激心肌细胞可见胞核内出现磷酸化ERK1/2荧光染色,丹参酮ⅡA可阻断AngⅡ引起的ERK1/2活化、入核过程;(3)用AngⅡ(1μmol·L-1)处理心肌细胞5min,磷酸化ERK1/2蛋白(p-ERK1/2)表达即开始增加,10min左右时最明显。以AngⅡ(1μmol·L-1)处理心肌细胞10min,磷酸化ERK1/2蛋白(p-ERK1/2)表达为标准,预先以STS(2,10,50μmol·L-1)处理心肌细胞30min,发现STS可明显抑制AngⅡ诱导的心肌细胞磷酸化ERK1/2蛋白表达;(4)预先以不同浓度STS处理心肌细胞30min,发现STS对AngⅡ诱导的心肌细胞磷酸化ERK1/2蛋白表达的抑制作用存在剂量依赖性。结论STS可以抑制AngⅡ诱导的心肌肥厚,其机制与抑制磷酸化ERK1/2表达有关。

Effect of Sodium tanshinone ⅡA sulfonate on activation of extracellular signal-regulated kinase1/2 in angiotensin Ⅱ-induced cardiomyocyte hypertrophy

Aim To observe effects of Sodium tanshinoneⅡA sulfonate(STS) on angiotensionⅡ(AngⅡ)-induced cardiomyocyte hypertrophy and the expression of phosphorylated extracellular signal-regulated kinase1/2 (p-ERK1/2). Methods In the primary culture of neonatal rat cardiomyocytes, as indexes of cardiomyocyte hypertrophy, the total protein was determined by coomassie brilliant blue and protein synthesis rate was measured by [3H]-Leucine incorporation. The expression of p-ERK1/2 was assessed using Western blot and fluorescence microscope. Results ① The total protein and protein synthesis rate stimulated by Ang Ⅱ(1 μmol·L-1)in the cardiomyocytes increased significantly in contrast to that of control; STS could effectively decrease the increased total protein level induced by Ang Ⅱand markedly inhibit synthesis of protein. ② AngⅡ(1 μmol·L-1) had the effect of promoting activation of ERK1/2 and then appeared in nucleus rapidly. The translocation process of ERK1/2 induced by AngⅡ was blocked distinctly by STS. ③ Cardiomyocyte pretreated with Ang Ⅱ(1 μmol·L-1)for 5 min, the p-ERK1/2 protein expression began to increase ,the peak effect was at 10 min. While pretreatment with STS(2, 10, 50 μmol·L-1) ,Ang Ⅱ-induced increase in p-ERK1/2 were inhibited evidently. ④ In pretreatment of cardiomyocyte with STS in different doses for 30 min, STS was found to be able to inhibit the expression of p-ERK1/2 stimulated by AngⅡ in a dose-dependent manner. Conclusions The results suggested that activation of ERK1/2 might play an important role in cardiomyocytes hypertrophy induced by Ang Ⅱ,and the anti-hypertrophic effect of STS on cardiomyocyte hypertrophy induced by AngⅡ might be associated to its inhibitory effect on ERK signaling pathway.