中文摘要：

目的探讨亚致死剂量6Gy γ射线一次性全身照射小鼠免疫细胞对脂多糖刺激反应性的远期影响。方法将实验小鼠分为假照射组和照射组，假照射组不接受照射，照射组给予6Gy γ射线照射。照射后10周，分别将假照射组和照射组小鼠按组别腹腔注射脂多糖（20mg／kg），对照组注射等量的生理盐水。分别于24h和1h后取材，进行外周血白细胞计数及CD4、CD8、B220细胞比例检测。取脾脏和胸腺称重，计算脏器指数。冲洗单侧股骨进行有核细胞计数。结果与假照射对照组小鼠相比，照射对照组小鼠的CD4细胞比例显著升高（t=2．940，P〈0．05），CD8和B220细胞比例显著下降（t=6．485和4．351，P均〈0．01）。照射＋脂多糖1h组小鼠的CD4（t=2．510，P〈0．05）、CD8（t=2．862，P〈0．05）和B220（t=7．074，P〈0．01）细胞比例较假照射＋脂多糖1h组小鼠显著降低，差异有统计学意义。与假照射＋脂多糖24h组小鼠相比，照射＋脂多糖24h组小鼠单侧股骨有核细胞计数显著升高，差异有统计学意义（t=2．078，P〈O．05）。结论6Gy γ射线一次性全身照射后10周，小鼠免疫系统尚未完全恢复；与假照射组相比，在接受脂多糖刺激后照射组小鼠胸腺指数和外周血中CD8和B220细胞比例未见显著变化。辐射对小鼠免疫系统损伤的远期影响有待进一步研究。

英文摘要：

Objective To investigate the long-term effects of high γ-ray dose on the mice immune system to stimulation of lipopolysaccharide （LPS）. Methods The mice were randomly divided into shamirradiation group and irradiation group. Mice in sham-irradiation group received no irradiation, while mice in irradiation group received 6 Gy γ-ray irradiation. The mice were accepted intraperitoneal injection of LPS （20 mg/kg） in LPS treated group at 10 weeks after inadiation,while the mice in control group were accepted intraperitoneal injection of saline. The mice were sacrificed after 1 h and 24 h respectively. The white blood cells, CD4, CD8 and B220 cells in peripheral blood were detected. The index of spleen and thymus were cal- culated and the number of bone marrow nucleated cells per femur were counted. Results Compared to the mice in sham-irradiation-control group, the ratio of CD4 cells in irradiation-control group increased （t=2.940, P〈0.05）, while the CD8 and B220 cells decreased （t=6.485 and 4.351, both P〈0.01 ）. Compared to the mice in sham-irradiation-LPS lh group, the ratio of CD4 （t=2.510, P〈0.05 ）, CD8 （t=2.862, P〈0.05 ） and B220 （t=7.074, P〈0.01 ） cells in iiTadiation-LPS 1 h group significantly decreased. Compared to the mice in sham-irradiation-LPS 24 h group, the number of bone marrow nucleated ceils in irradiation-LPS 24h group significantly increased （t=2.078, P〈0.05）. Conclusions The immune system of mice had not entirely recovered at 10 weeks after 6 Gy γ-ray irradiation. After the stimulation of LPS, the changes of thymus index and CD8, B220 cells numbers were less in the mice of irradiation group than the sham-irradiation group. The long-term effects of radiation on the mice immune system need to be further explored.