Abstract: To investigate the effects of Rhokinase on ischemia/reperfusioninduced cardiac apoptosis and the effects of the Rhokinase inhibitor, fasudil on cardiac apoptosis in cultured neonatal rat cardiomyocytes. MethodsNeonatal rat ventricular myocytes were prepared from hearts of 12 day old Sprague Dawley rat pups, and then subjected to ischmemia and reperfusion injury in vitro. Cultured neonatal cardiomyocytes were visualized with immunofluorescence staining. Cultured cardiomyocytes were randomly divided into three groups: the control group, the I/R group, and the I/R+fasudil group(treated with three concentrations of 10?μmol/L, 30?μmol/L and 50?μmol/L). The extent of phosphorylation of myosin phosphatase target subunit 1(MYPT1) was quantified by Western blot analysis, and the activity of the Rhokinase. Cardiac myocyte apoptosis ratio was determined by flow cytometry with AnnexinV and propidium iodide（PI）staining. ResultsCardiomyocyte ischemia reperfusion resulted in a 5.7fold increase in the amount of phosphorylated MYPT1 compared with the control group(P＜0.01 ). In contrast, treatment with fasudil at 10μmol/L， 30μmol/L and 50μmol/L attenuated the amount of phosphorylated MYPT1 by 24.6%, 40.1% and 60.1%, respectively (P＜0.05).　The cardiac myocyte apoptosis ratio were significantly decreased when myocytes was subjected to 3?h and 6?h reperfusion in the fasudil group in a dosedependent fashion compared with the I/R group. ConclusionsRhokinase induces cardiomyocyte apoptosis, however, the Rhokinase inhibitor, fasudil can decrease cardiomyocyte apoptosis and protect cardiac cells.

Key words: Fasudil, Ischemia/Reperfusion injury, Rhokinase, Apoptosis