碘缺乏对大鼠甲状腺的致癌性和对生育力的影响

CARCINOGENICITY OF IODINE DEFICIENCY IN RAT THYROIDS AND ITS INFLUENCE ON FERTILITY

目的与方法 :雌性wistar大鼠 ,喂缺碘饲料 4个月 ,引起碘缺乏病。继之 ,与正常健康雄性大鼠交配 ,观察雌性大鼠的生育力和甲状腺病变。结果 :每鼠每天摄取碘平均量 0 .92 6 μg ,极重度缺碘 ,甲状腺重量增加 ,并呈单纯性和结节性甲状腺肿。怀孕率呈降低趋势 ,活胎数为 6 .7± 2 .6个 /每孕鼠 ,对照组 10 .4± 3.3个 /每孕鼠 (P <0 .0 1)。排卵数 11.6± 1.9个 /每孕鼠 ,对照组 14.8± 2 .1个 /每孕鼠 (P <0 .0 1)。缺碘组大鼠甲状腺癌发生率 33.3% (7/ 2 1) ,均发生于有甲状腺滤泡增生的甲状腺肿的基础上 ,对照组无肿瘤发生 (0 / 12 ,P <0 .0 1)。结论 :结果说明 ,碘缺乏降低雌性大鼠生育力并具有明显的致癌作用 ,缺碘性甲状腺肿是甲状腺癌的癌前病变。

Purpose and Methods: Female Wistar rats were fed with iodie deficient diet for 4 months inducing iodine deficient diseases, then put 3 female with one male to mate each other for 5 days, and to observe the effects on female fertility and carcinogenesis. Results: In group of iodine deficiency, the average intake of iodine per animal was 0.926μg/day, it meaning extremely deficient. Their weight of thyroids was obviously increase, and showed simple goiter and nodular goiter. The number of living fetus significantly decrease to 6.7±2.6/pregnant rat, comparing with control 10.4±2.1/pregnant rat, P<0.01. The number of ovulation was also decrease to 11.6±1.9, comparing with control 14.8±2.1, P<0.01. The frequency of thyroid carcinoma was 33.3% (7/21), comparing with control 0.0%(0/12), P<0.01. All thyroid carcinomas were histologically derived from the base of follicular hyperplasia. Conclusion: The results mentioned above shows that the iodine deficiency must be decreasing the fertility, and having the strong carcinogenesis to the thyroids of female rats. Iodine deficient goiter is the precancerous lesion of the thyroid carcinoma.