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目的 :观察大剂量γ线照射对小鼠免疫功能近期、远期的影响。方法 :将 2 2 5只清洁级C5 7小鼠 ,随机分为 0、6、9、12、15和 2 0Gy 6个剂量组 ,经γ线全身 1次照射后 ,于照后 1～2 8d和 3～ 12月活杀取材 ,用原位末端标记 (TUNEL)和May Grunwald Giemsa(MGG)染色 ,检测细胞凋亡并观察其与照射剂量的关系。用流式细胞仪检测外周血T细胞亚群的变化。结果 :(1)照后早期 (1～ 14 )d外周血淋巴细胞的凋亡率即出现明显升高 ,随着照射剂量的增加凋亡率的升高更为显著 ;而T细胞亚群经不同剂量照射后持续下降 ,剂量为 2 0Gy时降至最低 ,其中以CD8+ T细胞对辐射的敏感性最高 ,因而推测早期的严重损伤是急性辐射免疫损伤的重要特点之一。 (2 )照射后 1月淋巴细胞的凋亡率降低 ,T细胞及其亚群也逐渐恢复。然而直至照后 6～ 12月 ,无论是淋巴细胞的凋亡率还是CD3+ T细胞及CD8+ T细胞亚群 ,均未恢复到对照的水平 ,提示大剂量辐射对机体免疫系统的损伤呈现较重的远期效应。 (3)本实验还发现 ,12≤Gy照射后 ,外周血淋巴细胞的凋亡率与照射剂量呈明显的剂量效应关系 ,15～ 2 0Gy照射后未观察到明显的量效关系。结论 :照射后早期外周血淋巴细胞的大量凋亡 ,可能是导致T细胞亚群的百分率急剧下降和后期免疫功能受损的重要原
Objective: To observe the effects of high-dose γ-ray irradiation on the immune function of mice in the short and long term. Methods: Twenty-five clean-grade C5 7 mice were randomly divided into 6 groups (0, 6, 9, 12, 15 and 20 Gy) And killed from March to December. TUNEL and May Grunwald Giemsa (MGG) staining were used to detect apoptosis and observe the relationship with irradiation dose. Detection of T lymphocyte subsets in peripheral blood by flow cytometry. Results: (1) The apoptotic rates of peripheral blood lymphocytes were significantly increased in the early (1 ~ 14) days after irradiation, and the apoptotic rate increased more significantly with the increase of irradiation dose. The T cell subsets Dose of different doses continued to decline, the dose was 20Gy to a minimum, of which CD8 + T cells were the most sensitive to radiation, suggesting that early severe damage is one of the important features of acute radiation-induced immune damage. (2) The rate of apoptosis of lymphocytes in January after irradiation decreased, T cells and their subpopulations gradually recovered. However, until 6 ~ 12 months after irradiation, neither lymphocyte apoptosis nor CD3 + T cells and CD8 + T cell subsets returned to the control level, suggesting that high doses of radiation on the body’s immune system damage appears heavier Long-term effect. (3) The experiment also found that 12? Gy irradiation, peripheral blood lymphocyte apoptosis rate and dose was significantly dose-related relationship, 15 ~ 20Gy irradiation did not observe a significant dose-response relationship. Conclusion: The large amount of apoptosis of peripheral blood lymphocytes in early stage of irradiation may be the important factor leading to the sharp decline in the percentage of T cell subsets and the impaired immune function in the later period