摘要
目的探讨长期摄入过量氟对大鼠甲状腺形态和功能的影响。方法将120只Wistar大鼠随机分为对照组(自来水,氟离子浓度0.344 mg/L)、低氟组(5 mg/L)、中氟组(10 mg/L)和高氟组(20 mg/L)4组。分别在饮水染毒第2、4、8个月末每组处死雌雄大鼠各5只。称取甲状腺重量,在光镜下观察甲状腺组织形态,用放射免疫法检测血清中促甲状腺激素(TSH)、总四碘甲腺原氨酸(TT4)、游离四碘甲腺原氨酸(FT4)、总三碘甲腺原氨酸(TT3)和游离三碘甲腺原氨酸(FT3)的水平,比较各组间指标差异。结果与对照组比较,染毒4、8个月末,高氟组大鼠TSH明显降低(P小于0.05);氟染毒各组TT4和FT4水平在染毒2个月末均明显增加(P小于0.05),之后呈降低趋势;在染毒过程中TT3和FT3水平无明显变化(P大于0.05)。在染毒2个月末,染毒组大鼠甲状腺即出现增生小滤泡,胶质减少,少数滤泡变大,滤泡上皮细胞扁平;随着染毒时间的延长,滤泡增生更加活跃,滤泡腔变小,部分甲状腺还可见融合巨滤泡。结论长期摄入过量氟可导致甲状腺形态和功能异常,且暴露时间可能是重要的影响因素。
Objectives To explore the influence of long term excessive fluoride intake on the morphology and function of thyroid in rats. Methods One hundred and twenty Wistar rats were randomly divided into a control group( tap water,fluoride concentration = 0. 344 mg/L) and three fluoride exposure groups: low fluoride group( 5 mg/L),medium fluoride group( 10 mg/L) and high fluoride group( 20 mg/L). Ten rats( female∶ male = 1∶1) in each group were sacrificed respectively after 2,4 and 8 months of exposure. Thyroid glands were weighed,the morphology of thyroid was observed under light microscope. The levels of serum TSH,TT 4,FT 4,TT 3 and FT 3 were detected by radio- immunological assay,and compared among groups. Results Compared with the control group, serum TSH levels in high fluoride group decreased significantly after 4 and 8 months of exposure( P less than 0. 05). Serum TT 4 and FT 4 levels of all fluoride exposure groups increased significantly after 2 months( P less than 0. 05),and then began to decrease. No significant changes of TT 3 and FT 3 levels were found after fluoride exposure( P more than 0. 05). The follicular hyperplasia and colloid reduction in thyroids were observed by the end of 2 months fluoride exposure,meanwhile,a small number of follicles grew bigger and follicular epithelial cell became flat. With the prolongation of fluoride treatment,follicular hyperplasia became more active,follicular cavity becomes smaller,and fusion giant follicular were observed in some thyroids. Conclusions Long term excessive fluoride intake could cause abnormal morphology and function of thyroid,and the prolonged time of fluoride exposure seemed to be a key factor.
出处
《环境卫生学杂志》
北大核心
2013年第5期390-393,397,共5页
JOURNAL OF ENVIRONMENTAL HYGIENE
基金
国家自然科国家学基金(30972555
81372934)
天津市医药卫生科技攻关项目(10KG215)
