白介素-6对受分次照射荷瘤小鼠脾细胞的辐射防护作用

探讨白介素-6(IL-6)对受照射荷瘤小鼠脾脏的辐射防护作用。6MV X射线对荷瘤小鼠进行分次全身照射(5Gy/5f/5d)后,采用黄嘌呤氧化酶法测定脾组织血清超氧化物歧化酶(T-SOD)活性,硫代巴比妥酸钠(TBA)荧光法测定氧化产物丙二醛(MDA)含量;免疫组化抗生蛋白链霉素-过氧物酶-生物素(SP)法检测脾细胞Bcl-2的表达;Beckman液体闪烁仪检测脾淋巴细胞亚群对K562细胞的杀伤活性。结果表明, IL-6组脾组织T-SOD含量明显增高(p<0.01),而MDA含量明显降低(p<0.05); IL-6组脾细胞Bcl-2的表达水平显著高于对照组(p<0.01);IL-6提高了脾淋巴细胞对K562细胞的杀伤活性。抗氧化酶活性的降低和氧自由基作用的增强是电离辐射引起细胞过氧化损伤,导致细胞功能异常的重要原因。IL-6可能通过促进脾细胞Bcl-2蛋白表达,增强脾细胞的抗氧化活性,抑制氧自由基对脾细胞的损伤,延长脾细胞寿命,增强其免疫功能而发挥辐射防护作用。

RADIOPROTECTIVE EFFECT OF IL-6 ON THE SPLEEN CELLS IN IRRADIATED TUMOR-BEARING MICE

The paper is to study radioprotective effect of Interleukin 6 (IL-6) on the spleen cells of irradiated tumor-bearing mice. After 6MV X-ray irradiation (5Gy/5f/5d), the activities of total superoxide dismutase (T-SOD) in spleens of irradiated tumor bearing mice were measured by the method of xanthineoxidase. The contents of malondialdehyde (MDA) were measured by thiobarbituric acid (TBA) fluorescence; Immunohistochemical technique was performed to detect Bcl-2 protein in spleen cells; The effects of IL-6 on natural killing activity of lymphocytes on K562 cells were determined by Beckman liquid scintillation counter IL-6 showed significant radioprotective effect on the spleen cells of irradiated tumor bearing mice, including increasing the activities of T-SOD (p<0.01) and reducing the contents of MDA (p<0.05). The increased expression level of Bcl-2 in spleen cells was obersved in the IL-6 group (p<0.01). IL-6 enhanced the natural killing activity of lymphocyte on K562 cells. Decrease of antioxidase activities and increase of free radicals may be the main causes of peroxidation induced by irradiation and damage to cell activities. IL-6 has radioprotective effect on the spleen cells, which may be due to its function of increasing the expression of Bcl-2 and antioxidase activities, eliminating free radicals, lengthening the life span of spleen cells and promoting their functions.