目的　研究磷脂酰肌醇 3 -激酶的特异性抑制剂Wortmannin(WT)对小鼠胸腺细胞DNA辐射损伤修复的影响 ,以探索WT放射增敏作用机制。方法　以 50 μmol/LWT作用小鼠胸腺细胞 ,以不同剂量γ射线照射 ,照射后不同时间制取细胞DNA ,用琼脂糖凝胶电泳方法检测DNA双链断裂 (dsb)。结果　WT单独对受照射细胞dsb产额无明显影响 ,抑制照射后dsb修复。结论　WT的放射增敏剂作用与其抑制照射后dsb修复有关 Objective To study the effect of Wortmannin (WT), a specific inhibitor of phosphatidylinositol 3 - kinase, on DNA damage in mouse thymocytes and to explore the mechanism of radiosensitization of WT. Methods Mouse thymocytes were treated with 50 μmol / L WT and irradiated with different doses of γ-rays. DNA was extracted at different times after irradiation. DNA double-strand breaks (dsb) were detected by agarose gel electrophoresis. Results WT had no significant effect on the dsb yield of irradiated cells alone and inhibited dsb repair after irradiation. Conclusion The radiosensitizer effect of WT is related to the inhibition of dsb repair after irradiation