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.