Roles of Rho-kinase in rat cardiac fibroblasts proliferation and collagen synthesis induced by angiotensin Ⅱ

AIM: To investigate the role of Rho-kinase signal pathway in rat cardiac fibroblasts (CFBs) proliferation and collagen synthesis induced by angiotensinⅡ (AngⅡ). METHODS: CFBs of neonatal Sprague-Dawley (SD) rats were isolated with the method of trypsin digestion and differential anchoring velocity. The CFBs were stimulated with AngⅡto induce fibrosis. Proliferation of CFBs was observed by MTT coloricmetric assay. Synthesis of collagen was detected by the hydroxyproline. The expression of Rho-kinase mRNA was examined using RT-PCR analysis. The extent of phosphorylation of myosin-binding subunit (MBS-P) of myosin phosphatase was quantified by Western blotting analysis, which was used to evaluate the activity of Rho-kinase.RESULTS: (1) Stimulation of neonatal SD rat CFBs with AngⅡ (10-7 mol/L) significantly increased CFBs proliferation and collagen synthesis (P<0.01). (2）Stimulation of neonatal SD rat CFBs with AngⅡ (10-7 mol/L) significantly increased the expression of Rho-kinase mRNA and rapidly activated Rho-kinase in a time-dependent manner. (3) Within a concentration coverage, hydroxyfasudil (H4413), a Rho-kinase inhibitor, effectively inhibited AngⅡ-induced CFBs proliferation and collagen synthesis (P<0.05 or P<0.01).CONCLUSION: Rho-kinase signal pathway may be one of the most important signal transducter for AngⅡ-induced CFBs proliferation and collagen synthesis in neonatal SD rats.