Effect of iodine on chemokine IP-10 expression in experimental autoimmunity thyroiditis rat / 中华地方病学杂志

ABSTRACT

Objective To establish experimental autoimmune thyroiditis (EAT) rat model induced by bovine thyroglobulin (bTg) and to observe the effect of iodine on IP-10 in rat serum and IP-10 mRNA expression in rat thyroid tissue.Methods One hundred and thirty-five four-week old female Lewis rats were divided into normal control (NC,20 rats) group;TG group,25 rats;H Ⅰ group,20 rats;H Ⅰ + TG group,25 rats;H Ⅱ group,20 rats and H Ⅱ + TG group,25 rats according to a random number table.The water iodine concentration was 25.7 μg/L given to rats of HⅠ and H I + TG groups,and 423.3 μg/L of H Ⅱ and H Ⅱ + TG groups.Rats of NC and TG groups drank distilled water.Rats of TG,H Ⅰ + TG,H Ⅱ + TG groups were immunized with 0.1 ml bTg (8 g/L) in IFA.All rats were killed at the end of 15 weeks.Urinary iodine was determined by As3+-Ce4+ catalytic spectrophotometry (WS/T 107-2006).Pathological changes in thyroid tissue were observed by light microscope.Serum IP-10 was determined by enzyme-linked immunosorbent assay (ELISA),and IP-10 mRNA expression in thyroid was detected by real-time PCR.Results The differences of urinary iodine between groups were statistically significant (x2 =106.4,P ＜ 0.05).Compared with NC group (456.45 μg/L) urinary iodine in other groups increased significantly (TG,H Ⅰ,H Ⅰ + TG,HⅡ,HⅡ + TG800.08,18 633.20,13 869.08,87 889.97,61 661.51 μg/L,all P ＜ 0.05).The pathological changes of rats in each group aggravated following increased iodine intake,NC group had normal thyroid structure;thyroid of TG group had a small amount of lymphocytes;thyroid of H Ⅰ group showed irregular follicular,part of the follicular was destroyed;a large number of lymphocytes infiltrated between follicular of H Ⅱ group;in H Ⅱ + TG group,the follicular was destroyed severely,diffuse inflammatory cell infiltration.The difference of serum IP-10 between groups no were statistically significant (F =1.462,P ＞ 0.05).The expression of IP-10 mRNA of H Ⅰ + TG (2.80 ± 1.73) rats thyroid was higher than that in NC (1.65 ± 1.62) and H Ⅰ (1.07 ± 1.00) groups,H Ⅱ (0.64 ± 0.64),H Ⅱ + TG (0.80 ± 0.49) were lower than H Ⅰ + TG group (all P ＜ 0.05).Conclusions Excessive iodine intake could have increased inflammatory cells in EAT rat and rats have showed more serious pathologic changes.These phenomena may be ralated with changed expression of IP-10 mRNA in EAT rat thyroid.