Protection of oxidative stress induced apoptosis in osteosarcoma cells by dihydromyricetin through down-regulation of caspase activation and up-regulation of BcL-2

Current study was aimed to investigate the effect of dihydromyricetin on hydrogen peroxide induced oxidative stress in the osteosarcoma cells. MTT assay showed that hydrogen peroxide treatment at a concentration of 100 mu M caused a significant (p<0.005) reduction in the viability of MG63 cells. However, reduction in cell viability caused by 100 mu M concentration of hydrogen peroxide was completely prevented on incubation with 30 mu M dose of dihydromyricetin. Treatment with 100 mu M concentration of hydrogen peroxide for 24 h led to condensation of chromatin material, rounding of cell shape and detachment of cells. The results from flow cytometry using annexin V-FITC and PI double staining showed apoptosis induction in 47.84 +/- 5.21% cells on treatment with 100 mu M concentration of hydrogen peroxide compared to 2.32 +/- 0.54% in controlcells. The apoptotic alterations in MG63 cell morphology were prevented significantly on pre-treatment with 30 mu M doses of dihydromyricetin for 48 h. Annexin V-FITC and PI staining showed reduction of hydrogen peroxide induced apoptotic cell percentage to 3.07 +/- 0.86% on pre-treatment of MG63 cells with 30 mu M dose of dihydromyricetin. Western blot analysis showed a significant increase in the activation of caspase-3 and -9 on treatment of MG63 cells for 24 h with 100 mu M concentration of hydrogen peroxide. The expression level of Bcl-2 was decreased significantly by 100 mu M concentration of hydrogen peroxide in MG63 cells. However, pre-treatment of MG63 cells with 30 mu M dose of dihydromyricetin for 48 h significantly prevented hydrogen peroxide induced increase in caspase-3 and -9 levels and reduction in Bcl-2 level. Thus dihydromyricetin prevents hydrogen peroxide induced reduction in viability and induction of apoptosis in MG63 cells through down-regulation of caspase activation and up-regulation of Bcl-2 levels. (C) 2016 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University.