Study On The Effects Of Different Iodine On Antioxidative Ability Of Iodine Deficient Rats

Universal salt iodization, which is the basis of major success in the elimination of iodine deficiency in our country, has induced controversy about the safety of iodized table salt lately. It has been shown that changes of antioxidative ability can be seen in the development of many diseases. Oxidative injury plays an important role in iodine induced thyroid diseases. Studies with radioactive iodine suggest that tissue distribution of radio iodine is very extensive, including thyroid, retina, liver, blood and others. Study shows that effect of iodine is not exclusively on the thyroid, but may well be systematic. However, publications about iodine' s effect on tissues other than thyroid are not enough. Therefore our study focus on the effects of dose factor and form factor of iodine, which is the main two expects of the current controversy, chose Wistar rat to establish animal model of iodine deficiency, and studied the effects of different iodine on the antioxidative capacity of retina, liver and blood.2*2 factorial experiment was carried out to investigate the interaction and main effects of the two factors. Iodine deficient Wistar rats were randomly divided into four groups, group of normal iodate(XO), group of normal iodide(NI), group of high iodate(HO) and group of high iodide (HI). Each group was supplemented with iodine in different doses and forms. The effects of iodine supplement on the elimination of iodine deficiency and antioxidative capacity were observed through a serial of indexes. Thyroid weight, urinary iodine concentration and thyroid hormones in serum including total TT3 and total TT.i were estimated at the 22nd week of iodine supplementation. GSH-Px > SOD , TAOC activities and MDA content in retina , liver homogenization were determined at 22 weeks. Antioxidative indexes of blood were determined dynamically at 22 and 28 weeks respectively. Histomorphology of the liver at the 22nd weeks was observed using light??microscope.Results showed: ?The effects of different iodine on the correcting of iodine deficiency: Dose factor had significant effect on the thyroid weight, urinary iodine concentration and serum thyroid hormone levels, Antioxidative activity was significantly higher in the groups with excessive dose in comparison with those groups with normal dose; Form factor showed effects only on the concentration of urinary iodine, group of potassium iodate significantly higher than group of potassium iodide in normal dose (NO>NI) , however comparison between groups of high dose was on the contrary (HI>HO) . (2)The effect of different iodine on the antioxidative ability of retina: Iodine didn't have any interaction between the dose and its form. Both dose and form factors of iodine showed some effects on antioxidative ability of retina in iodine deficient rat. The statistical analysis showed that a difference in SOD activity of retina homogenization was observed in different doses. It could be observed that SOD activity was significantly higher in the groups with normal dose in comparison with those groups with larger dose. In TAOC activity of retina homogenization, a significant difference due to the form factor was also seen. It means that TAOC activity was significantly higher in groups of KI than that in the groups of KIOV Although there was no statistical difference in GSH-Px activity, the tendency of GSH-Px activity was in accordance with SOD and TAOC, i. e. GSH-Px activity in groups of normal dosage higher than that in the groups of excessive dosage. Also GSH-Px activity in groups of KI was higher than that in groups of KIO:!. There was no significant difference in MDA content among the four groups. (3)The effect of different iodine on morphology and antioxidative ability of livers: No morphological change of the liver was observed among the four groups in light microscope. Changes of antioxidative ability suggested that both dose factor and form factor of iodine showed some effects on livers of iodine deficient rats. There was no statistical difference in GSH-Px activity...