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目的 :观察低剂量辐射 (LDR)诱导胸腺细胞凋亡及细胞周期进程适应性反应的基本规律。方法 :用 X射线照射昆明系雄性小鼠 ,其诱导剂量 (D1)及其后攻击剂量 (D2 )分别是 75m Gy和 1.5Gy。D1和 D2 间隔时间分别是 3、6、12、2 4和 6 0 h。D2 照射后 18h胸腺细胞培养 4、2 0和 4 4 h用流式细胞仪检测胸腺细胞凋亡小体 (TAB)和细胞周期进程的变化。结果 :当 D1和 D2 间隔 3、6和 12 h,在 D2 照射后胸腺细胞培养 4和 2 0 h,D1+ D2 组 TAB百分数明显低于 D2 组 (P<0 .0 5) ,G0 / G1和 G2 + M期细胞百分数也不同程度地低于 D2 组 ,而 S期细胞百分数却明显高于 D2 组 (P<0 .0 5或 P<0 .0 1)。结论 :D1和D2 分别是 75m Gy(剂量率 ,12 .5m Gy/ min)和 1.5Gy(剂量率 ,0 .2 87Gy/ min) ,D1和 D2 间隔 3～ 12 h,在小鼠全身照射后其胸腺细胞培养 4和 2 0 h可诱导细胞凋亡和细胞周期进程的适应性反应。
Objective: To observe the basic rules of adaptive response of thymocyte apoptosis and cell cycle progression induced by low dose radiation (LDR). Methods: Kunming mice were irradiated with X-ray and the induced dose (D1) and the subsequent challenge dose (D2) were 75 m Gy and 1.5 Gy, respectively. The interval between D1 and D2 is 3, 6, 12, 24 and 60 h, respectively. Thymocytes were cultured at 24, 20, and 44 h after irradiation with D2, and the apoptotic bodies (TABs) and cell cycle progression were detected by flow cytometry. Results: The percentage of TAB in D1 + D2 group was significantly lower than that in D2 group (P <0.05) at G4 / 2 and D0 / D2 after 3, 6 and 12 h intervals between D1 and D2, The percentage of cells in G2 + M phase was also lower than that in D2 group, but the percentage of cells in S phase was significantly higher than that in D2 group (P <0.05 or P <0.01). Conclusions: D1 and D2 were 75 m Gy (dose rate, 12.5 m Gy / min) and 1.5 Gy (dose rate, 0.87 Gy / min) respectively. D1 and D2 were separated 3 to 12 h after systemic irradiation Thymocytes cultured at 4 and 20 h induced apoptosis and cell-cycle adaptive responses.