Abstract:【Abstract】Objective To observe the effects of calcitriol on cellular proliferation in cardial fibroblasts induced by angiotenin II and explore its potenial roles and underlying mechanisms in preventing myocardial interstitial fibrosis.Methods Myocardial fibroblasts were cultured in vitro. and inferfered with AngII of final concentration in 10.6mol/L and calcitriol of final concentration in 10.6mol/L、10.7mol/L and 10.8mol/L。The cellular proliferation was detected by WST.1. The cellular cycle was assessed by flow cytometry using annexinV FITC.Results Calcitriol can inhibit the cellular proliferation in the condition of basic simulating by AngII.G1arrest significantly increased 22%.13% and 11% (P<0.05),compared with that of AngII group after 48 hours' action of different concentration calcitriol (10.6mol/L, 10.7mol/L and 10.8mol/L). The concentration dependence of calcitrial significantly decreased within the scope of 10.6mol/L, 10.7mol/L and 10.8mol/L .Cellular proliferation was inhibited by calcitriol through Glarrest(P<0.05). Conclusion Calcitriol inhibits cellular proliferation of myocardial interstitial fibroblast by Glarrest, and can prevent myocardial interstitial fibroblast caused by angiotensinII.