Impact of Fasudil on cardiac myofibroblast differentiation in pressure overload rats

Abstract

Objective Rho kinase mediated cytoskeleton actin reorganization plays an important role in the phenotypic differentiation of myofibroblasts. The study is to investigate the effects of Fasudil——a Rho kinase inhibitor——on myofibroblasts differentiation in pressure overload rats. Methods Pressure overload induced myocardial fibrosis rats models were established by abdominal aortic constriction. In sham group the abdominal aorta was just separated but not ligated. The 4 weeks after surgery, the operation survival rats were randomly divided into 3 groups: control model group, Fasudil high dose group (FH group) and Fasudil low dose group (FL group). And 4 weeks after the drug intervention, the degree of myocardial fibrosis was assessed as follows: pathologic changes were observed and hydroxyproline contents of the myocardium were determined; the content of angiotensin Ⅱ (Ang-Ⅱ) was calculated by enzyme linked immunosorbent assay (Elisa); the expression levels of phosphorylated myosin phosphatase target subunit 1 (p-MYPT1), α-smooth muscle actin (α-SMA), osteopontin (OPN) and transforming growth factor-β1 (TGF-β1) were analyzed by immunohistochemistry. Results Compared with the sham group, the degree of myocardial fibrosis in model group was aggravated variously, and the content of Ang-Ⅱ and the expression levels of p-MYPT1 (0.063±0.009 vs. 0.029±0.014), α-SMA (0.034±0.009 vs. 0.004±0.003), OPN (0.043±0.007 vs. 0.012±0.006) and TGF-β1 (0.058±0.019 vs. 0.019±0.009) were significantly increased (all P<0.01). Compared with the model group, the degree of myocardial fibrosis in FH group and FL group were relieved, and the content of Ang-Ⅱ and the expression levels of p-MYPT1 (0.029±0.013, 0.040±0.011), α-SMA (0.016±0.006, 0.027± 0.007), OPN (0.018±0.004, 0.036±0.006) and TGF-β1 (0.022±0.013, 0.039±0.014) were significantly decreased (P<0.05 or P<0.01). Conclusions The protection effect of Fasudil on myocardial fibrosis in pressure overloaded rats is at least partially related to the inhibition of myofibroblast differentiation. Key words: Myofibroblast; Fasudil; Pressure overload; Myocardial fibrosis