Embryonic Period And Lactation High Fluoride On The Developing Thyroid And Possible Mechanism

Objective:Excessive fluoride intake can lead to fluorosis on organism. Report shows that the functional and morphologically damage on thyroid were caused by high-fluorine intaken. We will explore the possibility and the principle that the thyroid damage on normal feed offspring rats were caused by the parental fluorosis.Methods:We divided 30 Wistar rats randomly into 2 separated groups which 10 for normal parental group (group N), 20 for high-fluoride parental group (group F). Group N drank normal water and group F drank high-fluorine water containing NaF with 100mg / l. The 2 groups of high-fluoride parental rats copulated separately after 7 months when Group F proved to be hypothyroid. The mother rats in Group F kept on feeding with high-fluorine water in their lactation. The rats were separated after 30 days and the offspring generation were divided into Group n & Group f. All the 2 groups of offspring rats were normally feed and selected after 4 months. The serum TT3, TT4 were mensurated by RIA method; Morphology of thyroid were observed by HE staining. The changes of glutamate receptor NR2B subunit expression in thyroid were tested using immunohistochemical analysis.Results : (1)Differences on Serum TT3, TT4: Serum TT3 from high-fluoride offspring group(Group f) is lower than normal offspring group(Group n)obviously(P<0.05). TT4 is lower than Group n also.(2)HE staining Differences in microscopy: The structure of follicular epithelium seems to be normal and orderly arranged, no hyperplastic or atrophy in filter cells for Group n. For all the cases in Group f, the hyperplasia can be found on follicular epithelium with high quantity and laminar, also with disorder, epithelium appears to be columnar or high columnar in shape, mastoid prominent at the follicular cavity, cell structure damaged, stromal capillaries distend with congestive, lumen distend, fibrous tissue with diffuse hyperplasia.(3)Discovered by staining on thyroid NR2B NMDA receptor, all the cases have overexpression of NR2B receptor. NR2B receptor staining brown on membrane and cytoplasm of thyroid acini. The result of average optical density: There is no differences in normal groups 122.99±4.17 for normal parental group with 115.17±6.46 for normal offspring group. NR2B positive cells in Group F were lesser than Group N and NR2B positive cells in Group n is lesser than Group f. The mean optical density for each group: F>N/n>f(P<0.01).Conclusion:1. With excessive intake of fluoride in parental rats, the offspring rats are affected by hypothyroid.2. With excessive intake of fluoride in parental rats, the offspring rats are affected by hypothyroid and thyroid structure damaged in normal environment.3. Attention should be paid to pregnant mothers, fetuses and newborn babies who are or were in high-fluoride environment. Patient should be treated with TH or thyroid preparations once they are hypothyroid because it is the most simple and convenient way to cure the hypothyroid, and it is absolutely safe to the patient.4. NR2B receptor for rats'thyroid can be staining by immunohistochemical analysis.5. (GLU) excitotoxicity should be a expression that the parental rats'fluorosis leads to the abnormal expression in NR2B receptor in both parental and offspring rats.6. It is possible that the principle of thyroid damage which affected by NR2B receptor is the cause of the damage in organism tissue which caused by fluorosis.