Objective:To investigate the effects of high glucose on apoptosis and expression of apoptosis-related genes in neonatal rat cardiomyocytes. Methods:Cultured cardiomyocytes were exposed to high glucose (20 mmol/L) for 48 h. Laser confocal microscopy, TUNEL assay and flow cytometry were utilized to detect cardiomyocyte apoptosis. Real-time PCR was performed to identify mRNA expression of apoptosis-related P53,Pax3, Bmp4,Slug and Msx1 genes in the glucose group and the control group. Results:Cardiomyocyte apoptosis was obviously observed in the glucose group under the laser confocal microscope. TUNEL assay indicated that cardiomyocyte apoptotic index in the glucose group was significantly higher than that in the control group (P < 0.05). Flow cytometry revealed that cardiomyocyte apoptotic rate in the glucose group was significantly higher than that in the control group (P < 0.05). Real-time PCR Showed that the expressions of P53 and Msx were up-regulated in the glucose group while the expressions of Pax3, Bmp4 and Slug were down-regulated. Conclusion:High glucose can disrupt apoptosis-related genes’ expression, including P53,Pax3, Bmp4,Slug and Msx1, which may be related to the cardiomyocyte apoptosis.