AimTo investigate the role of microRNA-29a (miR-29a) on apoptosis in rat cardiomyocytes.MethodsIn our study, newborn rats cardiomyocytes was isolated, cells were transfected with miR-29a mimic by lipofectamine RNAiMAX, and then real time RT-PCR was used to measure the level of miR-29a, flow cytometry (FCM) was used to detect the cells apoptosis, and western blot was used to detect the protein expressive level of Caspase-3 and Caspase-9.ResultsMiR-29a mimics could upregulate the level of miR-29a in rat cardiomyocytes after 48h of transfecting, accompanied with the increase of cells apoptosis rate, and descent of the protein level of caspase-3 and caspase-9 in cardiomyocytes when compared to the control group(P<0.05).ConclusionOur study demonstrated that the overexpression of miR-29a may regulate cells apoptosis of rat cardiomyocytes, and the mechanisms among it may be concerned with Caspase-3 and Caspase-9 pathway.