The effect of superoxide dismutase on spleen and peripheral blood in tumor-bearing mice suffering from oxidative injury induced by ionizing radiation

Objectives To study the protective effects of superoxide dismutase (SOD) on spleen and peripheral blood in tumor-bearing mice suffering from oxidative injury induced by ionizing radiation. Methods Tumor-bearing mice of Lewis lung cancer were divided into 3 groups: blank control group, radiation control group and radiation+SOD group (n=6 each). The mice were irradiated with 6 MV X ray (from a linear accelerator) for 5 consecutive days. Peripheral blood samples and spleen cell suspension were collected to determine the content of malondialdehyde (MDA) and the activities of glutathion (GSH), glutathione peroxidase (GSH-Px) and catalase (CAT) by chemocolorimetry. Results In the control group, irradiation elevated the content of MDA in spleen and blood (P0.05), and reduced the activities of GSH-Px and CAT (P0.05). SOD ip in the test group reduced the content of MDA in spleen and blood (P0.05); and elevated the activities of GSH, GSH-Px and CAT in spleen (P0.05), but not in blood (P0.05). Conclusion Irradiation injures the immunological function of tumor-bearing mice. Administration of SOD can protect the tumor-bearing mice against the oxidative injuries due to irradiation.