摘要
目的应用甲状腺球蛋白（Tg）诱导大鼠建立实验性自身免疫性甲状腺炎（EAT）动物模型，观察不同碘营养状态下大鼠甲状腺的病理改变和CD4＋T淋巴细胞的浸润程度。方法4周龄雌性Lewis大鼠135只（体质量约80g），按体质量采用随机数字表法分为对照组（NC）、模型组（TG）、高碘Ⅰ组（HⅠ）、高碘模型Ⅰ组（HⅠ＋TG）、高碘Ⅱ组（HⅡ）和高碘模型Ⅱ组（HⅡ＋TG），NC、HⅠ、HⅡ组每组20只大鼠，TG、HⅠ＋TG、HⅡ＋TG组每组25只大鼠。HⅠ、HⅠ＋TG组大鼠饮用含碘离子为25．7mg／L的去离子水，HⅡ组和HⅡ＋TG组大鼠饮用含碘离子为423．3mg／L的去离子水，NC和TG组饮用蒸馏水。TG、HⅠ＋TG、HⅠI＋TG组大鼠皮下注射含8．0g／L他的不完全弗氏佐剂0．1mI，两周1次，共3次。各组大鼠于建立模型后第8周，收集尿液；于建立模型后第15周末处死动物，采集血样、取甲状腺组织。砷铈催化分光光度法测定大鼠尿碘；苏木精．伊红（HE）染色法观察甲状腺组织病理学改变；免疫组织化学方法检测甲状腺组织炎性细胞水平。结果各组大鼠甲状腺相对质量组间比较差异有统计学意义（F=44．428，P〈0．05）。其中与NC组（0．08525mg／g）比较，各实验组大鼠甲状腺相对质量（TG、HⅠ、HⅠ＋TG、HⅡ、HⅡ＋TG组：0．09522、0．09285、0．09748、0．09655、0．09533mg／g）均升高（P均〈0．05）；各组大鼠尿碘组间比较差异有统计学意义（χ2=106．4，P〈0．05）。其中TG、HⅠ、HⅠ＋TG、HⅡ、HⅡ＋TG组大鼠尿碘（800．08、18633．20、13869．00、87889．97、61661．51μg／L）均高于NC组（456．45μg/L、P均〈0．05）。各组大鼠甲状腺病理改变随着碘摄入的增加逐渐加重。NC组大鼠甲状腺结构正常；TG、HⅠ组甲状腺滤泡间少量淋巴细胞浸润；HⅠ＋TG组可见淋巴细胞浸润到滤泡内部；HⅡ、HⅡ＋TG组滤泡融合，弥漫性炎细胞浸润。各组大鼠甲状腺随着碘摄入的提高CD4＋T淋巴细胞浸润程度有加重的趋势。NC组基本无CD4＋T淋巴细胞的阳性染色出现；TG组有少量阳性细胞；HⅠ组有散在的黄褐色阳性细胞；HⅠ＋TG组呈小灶性淋巴细胞浸润；HⅡ组滤泡扩张明显；HⅡ＋TG组滤泡结构破坏严重，呈弥漫性黄染。结论过量碘摄入和风免疫可诱发和加重大鼠自身免疫性甲状腺炎的发生，病理改变情况随着碘摄入的提高而加重。过量碘摄入还可使EAT大鼠甲状腺组织中CD4＋T淋巴细胞的浸润程度增加。
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 （HⅡ ）, high iodine and model-Ⅱ （HⅡ ＋ TG） groups according to body weight by random number table. There were 20 rats in NC, HⅠ and HⅡ groups, and 25 rats in TG, HⅠ ＋ 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 HⅡ and HⅡ ＋ 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 HⅡ ＋ 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 H, HⅡ ＋ 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（χ2 = 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 lymphocytes were found between thyroid follicular; the lymphocytes infiltrated into the follicular in HⅠ ＋ TG group; rats in HⅡ , HⅡ ＋ 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 H H ＋ 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.
出处
《中华地方病学杂志》
CAS
CSCD
北大核心
2014年第3期263-267,共5页
Chinese Journal of Endemiology
基金
国家自然科学基金（81072253）
作者简介
通信作者：刘守军，Email：liusj590406@163．com.
通信作者：于钧，Email：6yujun@126．com.
