A study of CD4+T lymphocyte infiltration level in the thyroid of experimental autoimmune thyroiditis rat
10.3760/cma.j.issn.2095-4255.2014.03.007
- VernacularTitle:实验性自身免疫性甲状腺炎大鼠甲状腺中CD4+T淋巴细胞浸润的研究
- Author:
Silu CUI
;
Shoujun LIU
;
Jun YU
- Publication Type:Journal Article
- Keywords:
Iodine;
Experimental autoimmunity thyroidits;
CD4+T lymphocyte
- From:
Chinese Journal of Endemiology
2014;33(3):263-267
- CountryChina
- Language:Chinese
-
Abstract:
Objective To establish a experimental autoimmune thyroiditis(EAT) rat model and to observe pathological change levels of CD4 + T lymphocyte infiltration in thyroid tissues under different iodine nutrient conditions.Methods One hundred and thirty-five four weeks old female Lewis rats(body weight about 80 g) were divided into control(NC),model(TG),high iodine-Ⅰ (HⅠ),high iodine and model-Ⅰ (HⅠ + TG),high iodine-Ⅱ (H Ⅱ),high iodine and model-Ⅱ (H Ⅱ + TG) groups according to body weight by random number table.There were 20 rats in NC,HⅠ and H Ⅱ groups,and 25 rats in TG,H Ⅰ + TG and H Ⅱ + TG groups.The rats of HⅠ and HⅠ + TG groups drank deionized water containing iodine 25.7 mg/L; rats of HⅡl and H Ⅱ + TG groups drank deionized water containing iodine 423.3 mg/L; rats of NC and TG groups drank distilled water.Rats of TG,HⅠ + TG and H Ⅱ + TG groups were immunized with 0.1 ml thyroglobulin(Tg,8.0 g/L) in incomplete Freunds adjuvant (IFA),once two weeks for three times.Urine samples were collected after immunization for 8 weeks; after immunization for 15 weeks,rats were killed,blood samples and thyroid tissues were taken.Urinary iodine was determined by arsenic-cerium catalytic spectrophotometry; pathological changes in thyroid tissue were observed by Hematoxylin-Eosin (HE) method ; immunohistochemical method was used to identify the infiltration of inflammatory cells in thyroid tissue.Results The difference of rat thyroid relative quality between groups was statistically significant (F =44.428,P ＜ 0.05).Compared with NC group (0.085 25 mg/g),thyroid relative qualities were increased in experimental groups (TG,HⅠ,HⅠ + TG,H Ⅱ,H Ⅱ + TG groups:0.095 22,0.092 85,0.097 48,0.096 55,0.095 33 mg/g,all P ＜ 0.05).The difference of urinary iodine between groups was statistically significant(x2 =106.4,P＜ 0.05).Compared with NC group(456.45 μg/L),urinary iodine levels in TG,HⅠ,HⅠ +TG,HⅡ,HⅡ + TG groups(800.08,18 633.20,13 869.00,87 889.97,61 661.51 μg/L) were increased(all P ＜ 0.05).The pathological changes of rats in each group were increased with increasing of iodine intake.Rats in NC group had normal thyroid structure; in TG,HⅠ groups,a small amount of lyrnphocytes were found between thyroid follicular; the lymphocytes infiltrated into the follicular in HⅠ + TG group; rats in H Ⅱ,H Ⅱ + TG groups had follicular fusion,and diffused inflammatory cell infiltration.There was a tendency of increased CD4+ T lymphocyte infiltration in rat thyroid with increasing of iodine intake.There was no CD4+ T lymphocyte positive staining in NC group; TG group had a small amount of positive cells; HⅠ group had scattered yellowish-brown positive cells.HⅠ + TG group had a focal lymphocyte infiltration; HⅡ group had follicular expansion obviously; follicular structure damage in HⅡ + TG group was serious,and showed a diffused yellow dye.Conclusion Excessive iodine intake and Tg immunization can induce and aggravate the incidence of autoimmune thyroiditis in rats,and pathological change situation has exacerbated with increasing of iodine intake; excessive iodine intake may also lead to an increased tendency of CD4+ T lymphocytes infiltration in thyroid tissue of EAT rat.
