Protective effect of gingko biloba against radiation-induced cellular damage in human peripheral lymphocytes and murine spleen cells

The present study was designed to determine the possible protective effects of Gingko biloba extract (EGb) against cellular damage induced by irradiation (IR) in human lymphocytes and C56BL/6 murine cells. Murine spleen cells were exposed to IR after pretreatment with either saline or EGb, and treatments were repeated immediately after IR. Then the mice were decapitated at either 6 h or 72 h after whole-body IR, where intraperitoneal injections of EGb or saline were repeated once daily. Human peripheral lymphocytes were observed for the determination of the frequencies of apoptotic cells. All samples were also examined microscopically and assayed for the frequencies of apoptotic cells. The frequencies of apoptotic cells in human peripheral lymphocytes increased significantly in the saline-treated IR groups, but decreased significantly in the EGb-treated IR groups. The sizes of the murine spleen in the saline-treated IR groups decreased significantly compared with those in EGb-treated IR groups. The data demonstrated that EGb, through its free-radical scavenging and antioxidant properties, attenuates IR-induced apoptosis in radiosensitive cells, suggesting that EGb may have a potential benefit in enhancing radioprotective effects.