亚致死剂量γ射线照射后小鼠脾脏CD95阳性淋巴细胞变化规律的研究

Characterization of expression of CD95 of splenic lymphocytes in sublethally γ irradiated mice

观察γ射线照射后小鼠脾脏淋巴细胞凋亡的变化规律与ＣＤ９５（Ｆａｓ）表达的关系。方法采用ＰＩ染色及双荧光流式细胞术研究不同剂量γ射线照射后不同时间，小鼠脾脏淋巴细胞凋亡及ＣＤ９５表达的规律。结果小鼠脾脏淋巴细胞对不同剂量照射的凋亡敏感性差异有显著性，４Ｇｙ照射后凋亡率最高（在２～６Ｇｙ之间观察），淋巴细胞表面Ｆａｓ的表达随照射后细胞凋亡率的变化而改变。结论脾脏淋巴细胞在辐射后表现出明显的Ｆａｓ介导的凋亡，Ｂ细胞较Ｔ细胞具有更高的辐射凋亡敏感性。

Objective\ The aim of this study was to investigate the apoptosis of splenic lymphocytes and CD95 expression in 60 Co γ irradiated mice. Methods\ Mice were whole body irradiated with 2.0, 4.0, 6.0 Gy γ rays. The splenic lymphocytes were analyzed by flow cytometry with fluorecscent monoclonal antibodies and PI in different times after irradiation. Results\ It was found that apoptosis occurred in the normal splenic tissues, Fas was expressed in resting mouse splenic lymphocytes and the expression varied in T cells and B cells. B cells expressed high levels of Fas than T cells. Within 2 hours after 4Gy irradiation, however, B cells and T cells upregulated Fas expression and thereafter downregulated the expression and died by apoptosis if Fas was crosslinked. Conclusions\ These observations suggest that the radiosensitivity varies with different doses of irradiation in mouse splenic lymphocytes. Fas mediated apoptosis plays a major role after irradiation of aplenic lymphocytes.