淫羊藿甙对辐照小鼠的抗凋亡作用与半胱天冬酶活性的相关性研究

目的：观察淫羊藿甙抗辐射损伤作用，并探讨其抗辐射损伤机制。方法：KM种小鼠于60Coγ射线照射前48，24h及照后即刻灌胃淫羊藿甙，剂量分别为1，10，100mg/kg，照射剂量8．0Gy，观察受照射小鼠30d存活率和死亡动物平均存活时间。另外观察淫羊藿甙对l锄种小鼠受5．5Gy 60Coγ射线照射后小鼠胸腺、脾脏和骨髓细胞凋亡率、半胱天冬酶-3(caspase-3)和半胱天冬酶-8(caspase-8))活性的影响。结果：中剂量淫羊藿甙组30d存活率较照射对照组提高50％，死亡动物平均存活时间延长2．5d。照射对照组胸腺、脾脏和骨髓细胞在照射后6，12和24h均有凋亡。胸腺和脾脏于照射后12h凋亡率最高，骨髓于照后6h凋亡率最高。照射24h后，3种组织的凋亡串均明显降低。中剂量淫羊藿甙可降低照射后6，12h胸腺、脾脏、骨髓细胞凋亡率和照射后24h脾脏、骨髓细胞凋亡率，抑制照射后6hcaspase-3活性，对半胱天冬酶-8活性无影响。结论：淫羊藿甙具有抗辐射损伤作用，其机制之一可能是通过抑制caspase-3活性降低细胞凋亡率。

Effect of icariine on cell apoptosis in irradiated mice and its relationship with activity of caspases

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.