Acteoside inhibits irradiation-mediated decreases in the viability and DNA synthesis of MC3T3-E1 cells

Therapeutic irradiation can cause bone loss, whereas antioxidant supplementation is considered to attenuate irradiation-mediated damages. This study examined whether or not acteoside inhibits irradiation-mediated changes in viability and proliferation of MC3T3-E1 cells. X-ray radiation at > 4 Gy not only decreased cell viability and DNA synthesis in the cells, but also increased intracellular levels of reactive oxygen species (ROS) and phosphorylated p66(Shc) protein. Irradiation at 8Gy also decreased intracellular levels of reduced glutathione (GSH) and induced G(1) phase arrest of cell cycle progression with the attendant increase of p21 induction. Pretreatment with acteoside inhibited the irradiation-mediated decreases in viability and DNA synthesis by restoring the radiation-mediated changes in the levels of ROS, GSH, p21, and p-p66(Shc) to the untreated control levels. These inhibitory activities of acteoside were greater than that of a synthetic antioxidant compound or N-acetyl cysteine did. Collectively, acteoside treatment may prevent irradiation-induced oxidative damages to osteoblasts.