Effcets of iodine on antioxidant system of liver and brain in rats with experimental autoimmune thyroiditis(EAT)

Objective To explore the effects of different levels of iodine on activities of superoxide dismutase(SOD) and glutathione peroxidase(GSH-Px) in EAT rats’liver and brain.Methods Female Lewis rats were chosen to make EAT model with pig thyroglobulin and divided into 4 groups randomly(control,model,model and excess iodine,and model and low iodine group).The pathological changes of thyroid gland tissue were observed and thyroglobulin antibody(TGAb),thyroid microsomal antibody(TMAb),activities of SOD and GSH-Px in rats’liver and brain were detected 8 weeks after the treatment.Results The lymphocytes infiltration was observed under light microscope in model and low iodine group.Some of thyroid folials were destroyed in model and excess iodine group.The main changes in rats iodine excess groups were expanding and confluence in thyroid follicle.The proliferation was the main change in rats of iodine deficiency group.Compared with that of model group,the levels of TGAb (75.00±15.44%)and TMAb(72.15±15.00%)in rats of model and low iodine group were significantly higher(P0.05).The activities of GSH-Px(122.01±10.34 mg·prot)and SOD(522.81±54.62 mg·prot)of rats’liver in model and low iodine group were lower than that of other groups (P0.05).The activity of brain GSH-Px(412.09±115.71 mg·prot)was the lowest in model and excess iodine group(P0.05).Conclusion Iodine deficiency and iodine excess in EAT rats may led to progress of the disease,and the effect of iodine deficiency seems more serious.