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.