中文摘要：

目的观察慢性低剂量微波辐照对大鼠外周血T、B淋巴细胞亚群的影响，探讨微波辐射致免疫组织损伤的效应和机制。方法清洁级雄性Wistar大鼠，按照微波辐照平均功率密度随机分为O（对照）、2．5、5、10mW/cm^24组，每天辐照6min，每周5d，连续辐照1个月，于辐照14d后以及连续辐照1个月后的1、30、60、180d活杀大鼠取材。采用血细胞自动分析仪进行外周血白细胞（WBC）计数，流式细胞仪检测胸腺组织中活性氧自由基（Ros）水平，以及大鼠外周血CD3^＋、CD4^＋、CD8^＋T细胞亚群和CD45RA^＋B细胞亚群的变化。结果①连续辐照结束后60d，外周血WBC在2．5mW／cm^2组较对照组明显升高（P〈O．05），在10mw／cm^2组明显降低（P〈0．01）。辐照后180d，各辐照组WBC较对照组明显降低（P〈0.05）。②连续辐照14d后，胸腺组织内ROS水平随辐照剂量增加而持续升高，呈较好的剂量-效应关系。辐照1个月结束后的60d，5mW／cm^2组ROS水平明显低于对照组（P〈0．05）。③辐照1个月结束后的1-60d，外周血T细胞亚群变化不明显，但辐照后180d，2．5mw／cm^2组CD3^＋和CD4^＋T细胞较对照组明显升高（P〈0．05），而5mW／cm^2组CD8^＋T细胞较对照组明显降低（P〈0．05）。各辐照组CD4^＋／CD8^＋比值虽然在辐照后180d出现升高趋势，但与对照组比较未见统计学差异。④辐照后60d，5mW／cm^2组外周血CD45RA^＋B淋巴细胞较对照组明显增加（P〈O．01），而辐照后180d，各辐照组CD45RA^＋B细胞却明显低于对照组（P〈O．05，P〈O．01）。结论大鼠经长期低剂量微波辐照后，免疫功能在早期改变不明显，晚期损伤较为明显，外周血WBC和CD45RA^＋B淋巴细胞在辐照后180d明显减少。

英文摘要：

Objective To observe the effects of long term low-dose microwave irradiation on rat peripheral T and B lymphocyte subpopulations, and to explore the mechanisms underlying microwave radiation-induced immunity injury. Methods A hundred healthy male Wistar rats （180±20g） were irradiated with 0, 2. 5, 5. 0 and 10. 0mW/cm^2 microwave, 6 minutes daily, 5 days per week, followed by continuous exposure for a month, and those in the normal group was sham-irradiated. Rats were sacrificed at day 14 of radiation, and day 1, day 30, day 60, and day 180 after the end of succeeding continuous irradiation for a month. Changes in WBC were estimated by automatic haemocyte analyzer, the intracellular free radical level of reactive oxygen species （ROS） in rat thymus and peripheral CD3^＋ , CD4^＋ , CD8^＋ T cell and CINSRA^＋ B cell subpopulations was analyzed by flow cytometry （FCM）. Results （1） Compared with normal group, peripheral WBC counts increased 60d after continuous exposure in 2. 5mW/cm^2 group （P〈0. 05）, and decreased in 10 mW/cm^2 group （P〈0. 01）. 180 days after irradiation the peripheral WBC count further decreased when compared with the control group （P〈 0. 05）. （2） ROS level in thymus tissue was persistently increased in a dose-dependent manner at day 14 of successive irradiation （P〈0. 05）, while it was lower in 5mW/cm^2 group than in control group 60 days after irradiation. （3） No statistical difference was found in the changes in CD3^＋ , CD4^＋ and CD8^＋ T lymphocytes in all groups exposed to irradiation from day 1 to day 60. However, 180 days after irradiation, CD3^＋ and CD4^＋ T cells in 2. 5mW/cm^2 group were obviously increased （P〈0. 05）, while CD8^＋ T cells in 5. 0mW/cm^2 group decreased significantly （P〈0. 05） as compared with control group. Meanwhile, CD4^＋/CD8^＋ ratio showed a tendency of elevation, though without significant difference, in all groups exposed to irradiation 180 days after radiation. （4） CD45RA^＋ B cells in