低剂量辐射诱导胸腺细胞凋亡及细胞周期进程适应性反应的剂量效应  

DOSE-EFFECT OF ADAPTIVE RESPONSE IN APOPTOSIS AND CELL CYCLE PROGRESSION OF THYMOCYTES INDUCED BY LOW DOSE X-IRRADIATION IN MICE

作　　者：龚守良[1] 刘淑春[1] 刘建香[1] 张迎春[1] 刘树铮[1] 

机构地区：[1]白求恩医科大学卫生部放射生物重点实验室,长春130021

出　　处：《辐射防护》2000年第5期294-298,共5页Radiation Protection

基　　金：国家自然科学基金资助课题! (编号 391 70 2 75)

摘　　要：本研究采用 X射线全身照射昆明系雄性小鼠模型 ,通过流式细胞仪观察低剂量辐射诱导胸腺细胞凋亡及细胞周期进程适应性反应的诱导剂量 (D1 剂量 )及其后攻击剂量 (D2 剂量 )的剂量范围。动物随机分为假照组、D2 对照组和 D1 + D2 实验组。结果表明 ,D1 + D2 组胸腺细胞凋亡小体百分数不同程度地低于 D2 组 ,并且减轻 G1 和 G2 + M期阻滞 ,导致 S期 DNA合成的细胞增加 ;当 D1 达 2 0 0 m Gy时 ,不再诱导胸腺细胞凋亡及细胞周期进程的适应性反应。本实验结果说明 ,D1 在 2 5～ 1 0 0 m Gy(剂量率为 1 2 .5m Gy/min) ,D2 在 1 .0～ 2 .0 Gy(剂量率为 0 .2 87Gy/min) ,接受 D1 和 D2 照射的时间间隔为 6 h。In the present study, male Kunming mice irradiated whole bodyly with X rays were used to observe the dose effect of adaptive response in apoptosis and cell cycle progression of thymocytes induced by low dose radiation. The mice were irradiated with inductive doses (D 1) of 25,50,75,100 or 200 mGy and challenge dose (D 2) of 1.0, 1.5 or 2.0 Gy, and divided randomly into 3 groups, such as group of sham irradiation, D 2 control group and D 1+D 2 group. The results showed that for D 1+D 2 group, the percentages of apoptotic bodies in thymocytes reduced in varying degrees,the arrests of G 1 and G 2+M phases diminished and the number of cells with DNA synthesis of S phase increased, as compared with D 2 group. When D 2 reached 200 mGy, the adaptive response in apoptosis and cell cycle progression of thymocytes were no longer induced by low dose radiation. The results mentioned above indicate that when the mice were irradiated with 25～100 mGy (D 1,12.5 mGy/min) at 6 h before 1.0～2.0 Gy (D 2, 0.287 Gy/min) exposure, the adaptive response in apoptosis and cell cycle progression of thymocytes may be induced under the condition of whole body irradiation.

关 键 词：电离辐射 胸腺细胞调亡 细胞周期 适应性反应 

分 类 号：R816[医药卫生—放射医学]