Protective Effects Of Isorhamnetin On Cardiomyocytes Against Anoxia/Reoxygenation-Induced Injury Is Mediated By SIRT1

Objective: Isorhamnetin(IsoRN) is a type of flavonoid.Many investigations have discovered thatIsoRNhas many biological activities such as anti-inflammatory, anti-tumor and cardioprotective effects. We established the cardiomyocytes from neonatal ratswith A/R injury model to demonstrate that SIRT1 may be involved in the protective effects of IsoRN on cardiomocytes against the A/R-induced injury.Method:In this study, the procedures of preparation of the cardiomyocytes from neonatal rats with A/R injurytreatment. The method of 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-Diphenyl-2H-tetrazolium bromide(MTT) assay was measure of cell viability. The effects on protein expression were measured by Western blot assay. The levels of mitochondrial membrane potential(??m), apoptosis, and intracellular reactive oxygen species(ROS) were detected by flow cytometry. The levels oflactate dehydrogenase(LDH), creatine phosphokinase(CPK)and activity of caspase-3 were monitored by colorimetric method.Results:1.Effects of pretreatment withIsoRN increased the cell viability and significantly decreased the levels of CPK and LDH activities in cardiomyocytes induced by A/R(p<0.01). 2.Pretreatment with IsoRN increased SIRT1 protein from the cardiomyocytes injure by the A/R(p<0.01). 3.Effects of pretreatment withIsoRNsignificantly decreased the ??m, reduced ROS generation, and decreased in cardiomyocytes apoptosisin cardiomyocyte by A/R(p<0.01). 4.IsoRNpretreatment inhibited the mPTP, activation of caspase-3,and the release of mitochondrial cytochrome c into the cytosol induced by A/R in cardiomyocytes(p<0.01). 5.Sirtinol, a SIRT1 inhibitor, drastically reduced the protective effects of IsoRN on cardioprotective effects by A/R in cardiomocytes.Conclusion: The protective effects of IsoRN on the cardiomyocytes against the anoxia/reoxygenation injury are mediated by SIRT1.