14MeV快中子辐照对大鼠免疫系统的损伤

用14 MeV快中子对Wistar雄性大鼠进行5 Gy的全身照射，观察其免疫系统损伤情况及氧化应激的相关变化.大鼠分为辐射组和对照组，分别在辐射后1，7，14d 3个时间点取血液、胸腺和脾脏进行研究.结果表明，辐照后第1d，辐照组大鼠白细胞和淋巴细胞数量降至最低，照后第7、14d有所恢复，但仍不足正常组的1/2.血小板数在照后第1d开始减少，至第7d达到最低值，第14d仍与正常组有显著差异.而大鼠骨髓有核细胞总数辐照后14d明显低于正常组.另外胸腺和脾脏均出现萎缩，脏器指数明显减小.血浆、胸腺和脾脏的总抗氧化能力T-AOC、SOD酶活性及MDA值含量均有不同程度的升高趋势.说明快中子辐射影响血浆、胸腺和脾脏的抗氧化应激能力，诱导细胞凋亡或坏死，造成胸腺和脾脏的萎缩以及一系列组织形态的改变，从而严重影响大鼠的正常免疫功能. 

Radiation Damage to Rat Immune System Induced By 14 Mev Fast Neutrons

In order to study the damage of immune system and antioxidant ability of rats induced by fast neutron, Wistar male rats were irradiated with 14 MeV fast neutrons on whole-body at the dose of 5 Gy. Wistar rats were randomly divided into control group and irradiation group. The blood, thymus, spleen and the oxidative damage (the level of SOD, MDA and T-SOD) were examined at 1, 7 and 14d after radiation. Compared with the control group, the number of white cells and lymphocytes of rats reached to a minimum at the first day after irradiation, and after 7 and 14d, was still less than the normal group. Platelet count began to decrease at first day, after exposure to seventh day, reaching a minimum value, and still had significant difference with that of the normal group at the fourteenth day. While the nucleated cell number in rat bone marrow after irradiation for 14 days was significantly lower than normal group. In addition, the thymus and spleen were shrinking, viscera index decreased significantly. The level of SOD, MDA and T-SOD of plasma, thymus and spleen increased in different degree. Results show that, fast neutron irradiation has effect on thymus, spleen and plasma, rising oxidative stress and apoptosis, resulting in spleen and thymus atrophy and a series of morphological changes, which seriously affect the immune function in rats.