摘要
目的 探讨低剂量辐射对致癌剂量辐射诱发小鼠胸腺淋巴瘤的影响及其免疫学机理。方法 采用 4次 1 75GyX射线全身照射C57BL/ 6J小鼠诱发胸腺淋巴瘤模型 ,观察不同剂量照后 6个月小鼠胸腺淋巴瘤发生率 ,照后 1个月脾脏NK细胞毒活性、IL 2和γ IFN分泌活性、腹腔巨噬细胞吞噬功能及其TNFα分泌活性以及胸腺细胞分化的变化。结果 每次 1 75Gy照射前 6h或 1 2h接受 2 5mGy或 75mGy全身照射均可降低胸腺淋巴瘤发生率 ,且预先接受 75mGy全身照射的作用效果更为明显 ;每次 1 75Gy照射前 1 2h接受 75mGy照射小鼠 ,上述免疫指标均比单纯1 75Gy照射组增强 ,且多数指标接近假照射组 ;其胸腺CD4- CD8- 和CD4- CD8+ 细胞较单纯 1 75Gy照射组减少、CD4+ CD8+ 细胞增多。结论 低剂量辐射可诱导辐射诱发胸腺淋巴瘤适应性反应 ,对致癌剂量辐射诱发小鼠胸腺淋巴瘤有抑制作用 ,其抑制作用的免疫学机理可能与低剂量辐射的免疫增强效应及诱导的免疫学适应性反应 ,减轻致癌剂量辐射对机体免疫功能的损伤 。
Objective\ To search for influence of low dose radiation (LDR) on thymic lymphoma (TL) induced by carcinogenic dose radiation in C57BL/6J mice and its immunologic mechanism. Methods The model was adopted that C57BL/6J mice were subjected to whole body irradiation with 1\^75 Gy X\|ray once every week for 4 weeks to induce TL.The incidence of TL was observed by microscopy 6 months after irradiation.The following indexes were examined:splenic NK cytotoxic activity,IL\|2 and γ IFN secretion activity,peritoneal macrophagic phagocytosis and its TNF α secretion activity,the changes of thymocyte differentiation in mice irradiated with different dose 1 month after irradiation. Results\ The incidencs of TL in mice irradiated with 25mGy or 75mGy 6h or 12h before 1\^75Gy irradiation were all lower than that in mice irradiated with 1\^75Gy only,and it is more obvious in mice irradiated with 75mGy prior to carcinogenic dose radiation.Immune parameters mentioned above in mice irradiated with 75mGy 12h before 1\^75Gy were higher than those in mice irradiated with 1\^75 only and the majority approached to those of the sham\|irradiated mice.The number of thymic CD4 -CD8 cells or CD4 -CD8 - cells was lower and CD4 +CD8 + cells was higher in mice irradiated with 75mGy 12h before 1\^75Gy than that in mice irradiated with 1\^75Gy only. Conclusion\ LDR can induce the adaptative response of radiation\|induced TL,and prevent or reduce the onset of radiation\|induced TL.The suppression mechanism may be related to the immunoenhancement effect and the adaptive response induced by LDR,decreasing immune function damage caused by carcinogenic dose radiation,eliminating thymic prelymphoma cells before they from solid tumor.\;
出处
《中华放射医学与防护杂志》
CAS
CSCD
北大核心
2000年第3期153-156,共4页
Chinese Journal of Radiological Medicine and Protection
基金
国家自然科学基金资助项目! ( 396 70 190 )
关键词
低剂量辐射
致癌剂量辐射
胸腺淋巴瘤
免疫功能
Low dose radiation
\ Carcinogenic dose radiation
\ Thymic lymphoma
\ Immune functions
