碘与小鼠甲状腺形态体视学的剂量反应关系

目的：研究不同剂量碘与小鼠甲状腺形态定量体视学的剂量－反应关系。方法：用随机区组实验设计方法将初断乳昆明小鼠84只随机分为7组,用碘酸钾配制成含碘50μg/L的适碘对照组和250μg/L,500μg/L,1000μg/L,1500μg/L,2000μg/L,3000μg/L高碘组,喂养100d后,观察甲状腺重量,肿大率,用HPIAS－1000图文分析系统对甲状腺滤泡及泡腔进行体视学参数测量,并计算甲状腺滤泡上皮细胞面积,体积占整个滤泡的百分比。结果：甲状腺绝对,相对重量,肿大率与碘剂量呈明显的正相关,并且甲状腺重量在250μg/L时与对照组比较差异有显著性,不同剂量高碘引起的小鼠甲状腺肿大率与人群流行病学调查结果相吻合,在500μg/L时与适碘组比较差异有显著性,甲状腺滤泡,滤泡腔的平均面积,面积体积,周长休整与碘剂量呈明显的正相关,而面数密度,比表面积滤泡上皮细胞的面积百分比,体积百分比与碘剂量呈明显的负相关,大多数参数在250μg/L时与对照比较差异已具显著性,结论：饮水碘浓度在250－3000μg/L时,甲状腺形态体视学参数与碘剂量呈明显的剂量－反应关系,引起的小鼠甲状腺肿大发生与人群流行病学调查结果相吻合,当饮水碘浓度为250μg/L时,即可引起高碘的胶质性甲状腺肿大。

The dose-response relationship study between the quantitative morphological stereology on thyroid and different iodine doses in mice

OBJECTIVE: To study the dose-response relationship between the quantitative morphological stereology on thyroid and different iodine doses in mice. METHODS: Weaning Kunming mice were randomly divided into seven groups. The mice were fed for 100 days with distilled water containing different KIO3 concentrations, i.e. 50, 250, 500, 1 000, 1 500, 2 000, and 3 000 microgram/L respectively. The 50 microgram/L (proper iodine concentration) group was control group, and the groups of 250 approximately 3 000 microgram/L were high iodine groups. The stereology parameters of thyroid follicle and follicular cavities were measured with HPIAS-1000 (High Resolution Pathological Image & word Analysis System). The stereology parameters included mean surface, volume on area, volume on circumference, specific surface, numerical density on area, spherical factor, the percentage of mean surface and mean volume of the follicular epithelial cell in thyroid follicle was further calculated. RESULTS: Positive correlations was observed between the thyroid absolute and relative weight, goiter rate and different iodine doses. And the thyroid absolute and relative weight of mice in the 250 microgram/L group was significantly different from that in 50 microgram/L group. The goiter rate of mice in different high iodine groups was in conformity with that of epidemiological investigation. The goiter rate of mice in 500 microgram/L group was different from that in 50 microgram/L group. Positive correlations were observed between mean surface, volume on area, volume on circumference, spherical factor and iodine doses, but the negative correlations were observed between numerical density on area, specific surface, the percentage of mean surface and mean volume of the follicular epithelial cell in thyroid follicle and iodine doses. CONCLUSIONS: When Iodine doses are between 250 approximately 3 000 microgram/L, the dose-response relationship was observed between the morphological stereology parameters of thyroid follicle and follicular cavities and iodine doses, and when the dose of iodine is 250 microgram/L, it is possible to induce colloid goiter of mice. The goiter rates of mice resulted by different high iodine doses were in conformity with that of the epidemiological investigation of people.