小剂量电离辐射增强小鼠免疫器官c－fos基因的表达

应用原位杂交方法观察７５ｍＧｙＸ射线全身照射后不同时间小鼠胸腺、脾、肠系膜淋巴结ｃ－ｆｏｓ基因ｍＲＮＡ转录水平的变化。结果发现，假照组胸腺、脾、肠系膜淋巴结内巨噬细胞、多突起细胞、部分淋巴细胞（主要为大淋巴细胞）ｃ－ｆｏｓｍＲＮＡ有低水平基础表达；７５ｍＧｙ全身照射后ｃ－ｆｏｓ的转录水平明显增高，胸腺为１ｈ达峰值，脾脏２ｈ达峰值，肠系膜淋巴结变比幅度较小，但持续时间较长。胸腺和脾脏阳性细胞１２ｈ基本恢复至假照水平，雨淋巴结细胞ｃ－ｆｏｓ至照后１２ｈ仍稍高于对照组。实验结果表明，小剂量电离辐射可使免疫活性细胞ｃ—ｆｏｓ的转录水平上调。

ENHANCED EXPRESSION OF c-fos PROTOONCOGENE IN MOUSE LYMPHOID ORGANS FOLLOWING LOW DOSE RADIATION

In situ hybridization was used to examine the expression of c-fos mRNA in mouse thymus, spleen and lymph node following whole body irradiation (WBI) with 75mGy X-rays. The results showed that the hasal expression of c-fos mRNA in macrophages, interdigitating cells and some ladle lymphocytes of thymus, spleen and mesenteric lymph node was markedly enhanced after WBI with 75mGy X-rays. The expression of c-fos mRNA in the thymus and spleen reached its peak 1 h and 2 h after irradiation respectively and both returned to the sham-irradiated level 12 h after irradiation. However, the increase in expression of c-fos mRNA in the lymph node was not so marked but lingered longer after irradiation. The implications of these findings were briefly discussed in connection with our previous data.