Sixty male mice were divided into six groups: normal control group (0 Gy), model control group (1.0 Gy), positive control group (1.0 Gy+523 tablet), and cimetidine groups (1.0 Gy) at the doses of 33.3, 100, and 300 mg/kg, respectively. The mice were irradiated to absorbed dose of 1.0 Gy with 60Co γ-rays at 8.33 mGy/min. Cimetidine was administered intragastrically 6 d before irradiation and 5 h after irradiation separately. Twenty-four hours after irradiation, the apoptosis rate of spleen lymphocytes, T lymphocyte subsets, and B lymphocytes in spleen, the content of IL-2, IL-4, IL-6, IL-12, IFN-γ, and TNF-α in serum were detected. Compared with normal control group, the apoptosis rate of spleen lymphocytes increased significantly (p<0.01). The percentage of CD3+, CD3+CD8+T lymphocytes, CD3?CD19+B lymphocytes, and the content of IL-4, IL-12, and TNF-α in serum decreased significantly (p<0.01, p<0.05). Compared with model control group, the apoptosis rate of spleen lymphocytes decreased (p<0.01), while the content of IL-4, IL-6, IL-12, IFN-γ, and TNF-α increased in serum of cimetidine groups (p<0.01, p<0.05). The percentage of CD3+, CD3+CD4+, CD3+CD8+, and CD3?CD19+cells increased in 300 mg/kg cimetidine group (p<0.01, p<0.05). Cimetidine could improve the immune functions of mice irradiated by γ-rays to 1.0 Gy.%雄性C57小鼠60只平均分为6组:正常对照组(0 Gy)、模型对照组(1.0 Gy)、阳性药对照组(1.0 Gy+523片)、西咪替丁(Cimetidine, CMD)低、中、高剂量组 (1.0 Gy+33.3、1.0 Gy+100、1.0 Gy+300 mg/kg),采用60Co γ射线全身照射至吸收剂量1.0 Gy,剂量率为8.33 mGy/min.CMD于照射前连续灌胃给药6 d,每天1次,照射后5 h给药1次.照射后24 h检测脾脏淋巴细胞凋亡率、T淋巴细胞亚群、B淋巴细胞数和血清中IL-2、IL-4、IL-6、IL-12、IFN-γ和TNF-α含量.结果表明:与正常对照组比较,照射后24 h,小鼠脾脏淋巴细胞凋亡率显著增加(p<0.01),CD3+、CD3+CD8+T细胞和CD3?CD19+B细胞数量均下降(p<0.01),血清中的IL-4、IL-12和TNF-α含量显著降低(p<0.01, p<0.05);与辐照模型组比较,CMD各剂量组脾脏淋巴细胞凋亡率显著下降(p<0.01),CMD给药组血清中IL-4、IL-6、IL-12、TNF-α和IFN-γ含量显著增加(p<0.01, p<0.05),CMD高剂量组的CD3+、CD3+CD4+和CD3+CD8+T细胞及CD3?CD19+B细胞数量均显著上升(p<0.01, p<0.05).结果提示,CMD可有效改善γ射线辐照小鼠的免疫功能,具有较好的辐射保护作用.
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