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目的探讨重组人铜锌超氧化物歧化酶（ｒｈＣｕＺｎ－ＳＯＤ）的辐射防护作用。方法观察６０Ｃｏγ射线５～７Ｇｙ照射对小鼠体内抗氧化酶和免疫细胞的影响，以及给予ｒｈＣｕＺｎ－ＳＯＤ后的抗放效应。结果与照射对照组比较，ｒｈＣｕＺｎ－ＳＯＤ可明显减轻受照小鼠血液和肝细胞浆中总超氧化物歧化酶（Ｔ－ＳＯＤ）、铜锌超氧化物歧化酶（ＣｕＺｎ－ＳＯＤ）、谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）、过氧化氢酶（ＣＡＴ）的活性下降的程度。ｒｈＣｕＺｎ－ＳＯＤ亦可明显增强受照小鼠脾Ｔ淋巴细胞对刀豆蛋白Ａ的增殖反应和自然杀伤细胞的活性；提高小鼠全脾淋巴细胞、外周血白细胞和相对淋巴细胞计数；以及延长了３０天平均生存时间。不同给药方法中，辐射前后给药组的效果优于辐射前或辐射后给药组。结论抗氧化酶活性的降低和氧自由基作用的增强可能是电离辐射引起机体过氧化损伤，导致组织细胞功能异常的重要原因。ｒｈＣｕＺｎ－ＳＯＤ对小鼠抗氧化酶和免疫细胞以及整体均具有辐射防护作用，可能主要由于其直接清除氧自由基的功能，其次通过这种保护功能也促进其他抗氧化酶发挥了一定的协同作用。
Objective To investigate the radioprotective effect of recombinant human copper-zinc superoxide dismutase (rhCuZn-SOD). Methods The effects of 60Coγ-ray 5 ~ 7Gy irradiation on antioxidant enzymes and immune cells in mice and the anti-proliferation effect of rhCuZn-SOD were observed. Results Compared with the irradiated control group, rhCuZn-SOD could significantly reduce the levels of total superoxide dismutase (T-SOD), copper-zinc superoxide dismutase (CuZn-SOD) Glycopeptide peroxidase (GSH-Px), catalase (CAT) decreased the degree of activity. rhCuZn-SOD also significantly enhanced the splenic T lymphocytes of irradiated mice on concanavalin A proliferation reaction and natural killer cell activity; increased mouse splenic lymphocytes, peripheral blood leukocytes and relative lymphocyte count; and prolonged 30 days average survival time. In different administration methods, the effect of radiation before and after administration group is better than that before radiation or after radiation. Conclusion The decrease of antioxidant enzyme activity and the enhancement of oxygen free radical may be the important reason that ionizing radiation can cause peroxidation injury and lead to abnormal function of tissue cells. rhCuZn-SOD has a protective effect on the antioxidant enzymes and immune cells in mice as well as the whole body, probably due to its direct scavenging function of oxygen free radicals and secondarily to synergistic effect of other antioxidant enzymes promoted by this protective function .