碘对妊娠期大鼠甲状腺形态变化及妊娠结局的影响研究

目的了解不同碘摄入量时大鼠甲状腺形态的变化及妊娠结局。方法选择体质量约80-100gWistar大鼠180只（雌性150只,雄鼠30只）,按体质量随机分成5组,每组30只。低碘1组（LI1）和低碘2组（LI2）大鼠食用病区粮食配方饲料,分别饮用含碘0、5μg/L去离子水;对照组（NI）、高碘1组（HI1）、高碘2组（HI2）大鼠食用市售普通粮食配方饲料,分别饮用含碘50、3 000、10 000μg/L去离子水。饲养3个月,雌鼠与雄鼠合笼交配,于孕早期（5±2）d、孕中期（12±2）d、孕晚期（17±2）d处死母鼠,记录妊娠结局,光镜下观察母鼠甲状腺病理学改变。结果 （1）LI1组和LI2组甲状腺绝对质量（121.66±54.12）、（32.60±12.09）mg]和相对质量（41.55±17.95）、（11.23±3.58）mg/100g]与NI组（20.45±5.02）mg、（5.88±1.44）mg/100g]比较显著增加,差异均有统计学意义（P〈0.01,P〈0.05）。（2）光镜下观察,与对照组比较,LI组甲状腺呈典型的小滤泡增生性;HI组甲状腺滤泡上皮细胞单层呈扁平状,核呈梭型,滤泡腔变大。（3）孕鼠孕中期,LI1组和LI2组的死胎率（39.88%,22.22%）显著高于NI组（5.52%,P〈0.01）;孕晚期,LI组和HI组（42.96%,32.05%,16.13%,13.04%）孕鼠的死胎率显著高于NI组（4.29%,P〈0.01或P〈0.05）。结论机体长期摄入碘过量对胚胎发育有一定的影响。

Study of the effects of different iodine levels on morphological changes of thyroid and pregnancy outcomes in pregnant rats

Objective To understand morphological changes of thyroid and pregnancy outcome in rats with different iodine intake. Methods Select 180 Wistar rats（ 150 famale and 33 male）,who weighed between 80 to 100 g,150 female rats were randomly divided into five groups according to their body weights,every group including 30 rats. Animals in the low iodine groups（ LI 1 and LI 2） were fed with low-iodine diet and drank deionized water which contained potassium iodate,the dose was 0,5 μg / L. The rats of adequate（ NI） and high iodine group（ HI 1 and HI 2） were fed with normal diet, they also drank deionized water, which the dose of contained potassium iodate were 50,3 000,10 000 μg / L. The rats mated after fed for 3 months,then the rats were respectively sacrificed at the first trimester（ 5±2 days）, the second trimester（ 12 ±2 days）,and the third trimester（ 17 ±2 days） to observe pregnancy outcome and their maternal pathological changes of thyroid by light microscope. Results ①Compared with the NI group, the thyroid absolute quality and relative quality of LI 1 and LI 2 groups increased significantly（ P 0. 01 or P 0. 05）,and the differences were statistically significant. ② Observed under light microscope, the thyroid of low iodine group showed a typical follicular hyperplasia goiter,the follicular epithelial cells of high iodine group gradually become thallus,the nuclear become shuttle,the cavity of follicle gradually spread compared with control group. ③In the second trimester of pregnancy, the fetal death rate of two LI groups（ 39. 88%,22. 22%） were significantly higher than that of NI group（ 5. 52%, P 0. 01）; In the third trimester, the fetal death rate of LI and HI groups（ 42. 96%,32. 05%,16. 13%,13. 04%） were significantly higher than that of NI group（ 4. 29%, P 0. 01or P 0. 05）. Compared with the adequate group, low iodine and high iodine intake resulted in an increased rate of decreased number of live fetuses at the third trimester. Conclusions Long-term intake of an excess of iodine in rats could have a certain impact of embryonic development.