长期低硒、低碘对子代发育期大鼠甲状腺形态结构及PCNA表达的影响

目的:研究长期低硒、低碘饲料喂养对子代发育期大鼠甲状腺组织形态结构以及PCNA表达的影响。方法:选取人工低硒、低碘饲料喂养繁殖的SD大鼠模型的仔3代胎鼠(F3E)、4日龄(F3P4)、21日龄(F3P21)、成年(F3A)4个时间点的甲状腺石蜡标本,常规切片,苏木精-伊红染色,免疫组化染色,镜下观察,滤泡计数。动物模型分为对照组,低硒(Se-)组,低碘(I-)组和低硒、低碘(Se-I-)组,各组分别喂以不同硒、碘水平的人工配制饲料,繁衍至仔4代。取甲状腺,制做石蜡切片。结果:各发育期时间点I-组与Se-I-组甲状腺体积增大,重量增加,滤泡增生,排列紧密。这种增生现象从胎鼠期间即有出现。在成年大鼠Se-组甲状腺滤泡有坏死和纤维化。PCNA在Se-I-组与I-组均强阳性表达,强阳性表达百分比依次为成年Se-I-组50%,I-组28.6%。21 d Se-I-组21.4%,I-组16.7%。结论:低碘和低硒、低碘均可致仔代发育期大鼠甲状腺滤泡明显增生。这种增生现象在胚胎期即表现。低硒能引起部分仔代大鼠甲状腺滤泡的坏死与纤维化。

Effect of Longtime Selenium and Iodine Deficiency on Histomorphology and PCNA Expression of Thyroid Gland of Rat at Development Stage

Objective: To study the effects of longtime selenium(Se)and iodine(I)deficiency on histomorphology and PCNA expression of thyroid gland of rat at development stage.Methods: The paraffin specimens of thyroid gland of the third generation rats with the age of embryo(F3E),4 days(F3P4),21 days(F2P21),adult(F3A) as four time points of research subjects were chosen.The sections of paraffin specimens were hematoxylin-eosin stained and immunohistochemistry stained, and then observed under microscope.The follicles were counted under microscope.Healthy SD rats were divided into control group,Se-deficient group(Segroup),I-deficient group(I-group) and both Se-and I-deficient group(Se-I-group).The rats in each group were given the artificial feeds containing different levels of Se and I.These rats were bred to the fourth generation.Results: At each research time points,the goiter was produced in I-group and Se-I-group and the thyroid weight and volume were increased between two groups.Under microscope,the features of small follicular proliferation were observed.The number and density of follicles were increased.The volume of follicles,the surface and the thyroid colloid of follicle cavity were decreased.These features were observed in I-group and Se-I-group of each time points.The follicular necrosis and fibrosis were observed in Se-group of adult rat.The strong expression of PCNA occurred in Se-I-group and Se-group,Se-I-group 50.0%,I-group 28.6% in adult,Se-I-21.4%,I-16.7% in 21-day.Conclusion: Simple selenium deficiency does not induce the thyroid follicular proliferation.Simple iodine deficiency and both selenium and iodine deficiency greatly induce the thyroid follicular proliferation.