Objective:To investigate
antiradiation effect of icariine and its mechanism. Methods:Kunming mice were exposed to whole
body
irradiation at dose of 8?Gy, and administered intragastrically with icariine 48 and 24?hours before and immediately after irradiation at the dosages of 1?mg/kg,10?mg/kg,100?mg/kg, respectively. Thirty_day survival and the average life_span of dead mice after irradiation were recorded. In addition, the effect of icariine on apoptosis rates and activities of caspase_3 and caspase_8 in mice exposed to 60 Co gamma irradiation at a dose of 5.5?Gy were observed. Results:The 30_day survival rate in medium dose of icariine group increased by 50% compared with irradiated control group, while the average life span of the dead mice prolonged by 2.5 days.The apoptosis rates of thymus, spleen and marrow cells all increased 6,12 and 24?hours after irradiation, but the apoptosis rates were lower significantly 24?hours after irradiation than those 6 and 12?hours after irradiation. Medium dose of icariine diminished apoptosis rates of all the three types of cells at 6 and 12?hours post_irradiation and reduced the apoptosis rates of spleen and marrow cells at 24?hours post_irradiation. Data also revealed that activities of caspase_3 and caspase_8 increased at 6?hours post_irradiation. Medium dose of icariine diminished caspase_3 activity but had no effect on caspase_8 activity. Conclusions:The results indicate that icariine has
antiradiation effect and one of its mechanisms might be restraint of caspase_3 activity and attenuation of apoptosis of cells in irradiated mice.