| Objectives We aim to discuss the influence of iodine supplement during pregnancy and lactation period on the thyroid and mammary glands of lactating rats through investigating the changes of TR?1 and TR?1 in protein and m RNA levels along the role of NIS and Dio1 in self-regulation.Methods The pregnant rats were randomly assigned into NI groups,10 HI groups and 100 HI groups.Iodide intake was 7.5 ?g/d,75 ?g/d and 750 ?g/d by feeding with normal diet and different concentrations of KI solution.The rats were sacrificed on the lactation days 7,14 and 21.Median urinary iodine concentration and iodine content in the thyroid and mammary glands were measured by As-Ce catalytic spectrophotometry;the body weight and the thyroid weight were measured,the ratio of thyroid weight/body weight was calculated;serum thyroid hormone levels were measured by competitive immune method of direct chemiluminescence technology and ELISA method respectively;mitochondrial superoxide production in thyroid and mammary glands was measured by flow cytometry using Mito SOX Red;Western blot was used to detect the expression of TR?1,TR?1 and NIS in protein levels;QPCR was used to detect the expression of TR?1,TR?1,NIS and Dio1 in m RNA levels;the morphologic features of thyroid and mammary tissues were observed under light microscopy following HE;the spacial distribution of TR?1,TR?1,NIS and CD4+T lymphocyte along with the expression of TR?1 and TR?1 were observed following immunohistochemical staining.Results1.The Ratio of Thyroid Weight / Body Weight: there were no significant changes in each groups(p > 0.05).2.Median Urinary Iodine Concentration and Iodine Content: compared to NI group,the median urinary iodine concentrations,iodine content in the thyroid glands and mammary glands in 10 HI group and 100 HI group was increased significantly(p <0.05);compared to 10 HI group,these indicators was also increased significantly(p3.< 0.05)on L7,L14 and L21.4.Serum Thyroid Hormones Levels: compared to NI group and 10 HI group,the FT3,FT3/FT4 levels in 100 HI group were significantly decreased along with FT4,TPOAb and Tg Ab levels were significantly increased(p < 0.05)on L7,L14 and L21.4.Western blot and QPCR: compared to NI group and 10 HI group,the expressions of TR?1,TR?1 and NIS in proteins and m RNA levels in thyroid and mammary glands in the 100 HI group were significantly decreased(p < 0.05);compared to the NI group,the expression of NIS in protein and m RNA levels in thyroid glands in 10 HI group was also decreased significantly(p < 0.05)on L7,L14 and L21.5.Mitochondrial superoxide production: the production of mitochondrial superoxide in the 100 HI group in thyroid and mammary glands were significant increased compared with those in the NI group and 10 HI group(p < 0.05)on L7,L14 and L21.6.HE: the structure of thyroid and mammary glands in the 100 HI group was destroyed seriously with some acini together.Lymphocytic infiltration among the thyroid follicles was seen in the 100 HI group.7.Immunohistochemical Staining: the protein expressions of TR?1 and TR?1 in thyroid and mammary glands were decreased when the intake of iodide was increased from NI to 10 HI and further to 100 HI on L7,L14 and L21.TR?1 and TR?1 is located in the nucleus.NIS is located in the cytoplasm,Occasionally seen in the cell membrane in the NI group.CD4+T lymphocyte were observed in the 100 HI groups in thyroid glands.Conclusion1.10 times iodine supplement during pregnancy and lactation period can maintain normal thyroid function through the increasing of urinary iodine excretion together with the decrease of NIS and breast lactation.2.100 times iodine supplement during pregnancy and lactation period may lead to thyroid lymphocyte infiltration in lactating rats,and abnormal TR?1and TR?1 may affect TH-mediated physiological activity and normal transcription. |
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