RESUMO
OBJECTIVE: To study the effects of iodine supplementation (in different kinds and doses) on the antioxidative ability of retina in iodine deficient rats. METHODS: One hundred and twenty eight iodine deficient Wistar rats were randomly divided into four groups, normal dose of iodate, normal dose of iodide, high dose of iodate and high dose of iodide. Concentration of serum thyroid hormones, including total TT(3) and total TT(4), were estimated by radioimmunoassay. GSH-Px, SOD, TAOC activities and MDA content in the retina were determined using biochemical methods in the 22nd week of iodine supplementation. RESULTS: Statistical analysis showed that a significant difference in TT(3) level of serum was observed between animals treated with different doses. Serum TT(3) level in the groups treated with high doses was significantly higher than those with normal doses. However, no statistical difference could be detected at TT(4) level between animals treated with different doses. Different kind of iodine did not affect the level of thyroid hormones. Statistical analysis showed that a difference in SOD activity of retina was observed between animals treated with different doses. SOD activity in the groups with normal doses was significantly higher than that in groups with larger doses. Retina TAOC activity was significantly higher in groups treated with iodide than that in groups of iodate. Although there was no statistical difference in GSH-Px activity between different groups, it showed the same tendency as the SOD and TAOC activities, i.e. GSH-Px activity in the groups of normal doses was higher than that in the groups of high doses. GSH-Px activity in groups of iodide was higher than that in the groups of iodate. There was no significant difference in MDA content among these four groups. CONCLUSIONS: Different iodine and doses have certain effects on the antioxidative ability of retina in iodine deficient rat. The rats supplemented potassium iodide at normal dose showed higher antioxidative ability of the retina than those of the others.