Adaptive response of thymocyte apoptosis induced by X-irradiation with 75 mGy

Objective:In present study we observed the adaptive response of thymocyte apoptosis induced by low dose radiation (LDR). Methods: In the experiment the medel of Kunming male mice with whole-body irradiation (WBI) was used. The inductive dose(D1) was 75 mGy and the challenge dose (D2) was 1.5 or 2.0 Gy. The interval time between D1 and D2 was 6h. Results: The percentages of thymocyte apoptotic bodies (TAB) in D1+D2 group 18 h after WBI with D2 were significantly lower than those in D2 group (P0. 05). In addition, when the extracellular fluid of the splenocytes irradiated with 75 mGy was put into the thymocyte suspension irradiated with 2. 0 Gy,the percentages of TAB after the incubation for 72 h were significantly lower than those in 2. 0 Gy irradiated thymocytes (P0.05). Conclusion:These results suggest that LDR (75 mGy) could change the external environment of immune cells,decrease the thymocyte apoptosis and induce an adaptive response of thymocyte apoptosis in the mice irradiated subsequently with larger dose (1. 5 or 2.0 Gy) of X-rays.