Abstract: AIM: To observe the inhibition effects of total saponin from Panacis majoris rhizoma on myocardial apoptosis of neonatal rat induced by H₂O₂ and its mechanism.METHODS: Oxidative stress-induced injury model was established with H₂O₂. Effects of total saponin from Panacis majoris rhizome (100, 200 μg/mL) on viability of cells and oxidative stress-induced apoptosis of cells were detected by MTT assay; Cell apoptosis rate and reactive oxygen species(ROS)content were detected by flow cytometry, the apoptosis cells morphous were observed by hoechst33258 through fluorescence microscope; The levels of Caspase-3, 9 were measured by detecting kits; Real-time polymerase chain reaction was applied to detect the mRNA expressions of Bcl-2 and Bax apoptosis-related genes.RESULTS: Total saponin from Panacis majoris rhizome (100, 200 μg/mL) might significantly increase cell viability and mitochondrial membrane potential, inhibit myocardial apoptosis, improve cell morphous, decrease intra-cellular ROS contents, down-regulate mRNA expression of Bax, up-regulate the mRNA expression of Bcl-2 and Bcl-2/Bax ratio, decrease activities of Caspase-3, 9, and with the dose of total saponin increasing, the aforesaid improvement became more and more strong.CONCLUSION: Total saponin from Panacis majoris rhizome could effectively inhibit myocardial apoptosis of neonatal rat induced by H₂O₂. The mechanism may be related to stabilizing mitochondrial membrane potential, scavenging of ROS, regulating the Caspase-3, 9, Bcl-2 and Bax expression levels.

Key words: Total saponin from Panacis majoris rhizome, H₂O₂, Cardiomyocytes, apoptosis, Bcl-2, Bax, Caspase-3, Caspase-9