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目的 研究核反应堆裂变中子诱导小鼠胸腺细胞凋亡的剂量效应 ,并与6 0 Coγ射线的效应相比较 ,探讨两种辐射诱导细胞凋亡的异同。方法 用光镜和电镜形态学观察与DNA琼脂糖凝胶电泳方法对细胞凋亡进行定性研究 ;用流式细胞术 (FCM )和二苯胺 (DPA)法对其进行定量研究。结果 小鼠经裂变中子 0 5～ 5 0Gy照射后 6h ,可检测到胸腺细胞的DNAladder,光镜及电镜下可观察到胸腺细胞典型的凋亡形态 ,且其凋亡比例随着照射剂量的增高而增加 ;γ射线 1 0～3 0Gy照射后 6h ,也都检测到胸腺细胞的DNAladder,其凋亡比例随剂量增高而增加 ,2 0Gy左右达到峰值 ,剂量再高 ,其凋亡比例不再增加。结论 0 5～ 5 0Gy的裂变中子或 1 0～ 3 0Gy的γ射线照射小鼠 ,均可引起胸腺细胞发生凋亡 ,且随剂量的变化规律相似 ;但裂变中子诱导小鼠胸腺细胞凋亡的效应高于γ射线 ,其RBE值约为 2 0 9(FCM法 )或 2 3 7(DPA法 )。表明中子对小鼠免疫组织的损伤在照射后几小时就比γ射线重 ,这可能是后期免疫组织损伤较重的基础。
Objective To study the dose-effect induced by nuclear fission neutrons in mouse thymocytes and to compare the effects of 60 Co γ-rays on the apoptosis induced by radiation. Methods Morphological observation and DNA agarose gel electrophoresis were used to qualitatively study the apoptosis of cells. Quantitative study was carried out by flow cytometry (FCM) and diphenylamine (DPA). Results The DNAladder of thymocytes detected by fission neutrons at 0-5 ~ 50 Gy irradiation for 6 hours showed typical apoptosis patterns of thymocytes under light and electron microscopes. And the DNAladder of thymocytes were also detected at 6h after γ ray irradiation at 10 ~ 30 Gy. The apoptotic ratio of thymocytes increased with the increase of dose and reached the peak at around 20 Gy, the dose was no longer high increase. Conclusion 0 5 ~ 5 0Gy fission neutrons or 10 ~ 30 Gy γ-rays can induce apoptosis in thymus cells, and their changes with dose are similar. But fission neutrons induce thymus apoptosis in mice The effect of death is higher than that of γ-rays with an RBE of about 290 (FCM) or 230 (DPA). It shows that the neutron damage to the mouse’s immune tissue is heavier than the gamma ray in a few hours after irradiation, which may be the basis for the later immune tissue injury.