Effects of intrauterine exposure to thyroid dysfunction on the development of brain neurons in neonatal rats / 中华内分泌代谢杂志

ABSTRACT

Objective To investigate the expression of MCT8, DCX, SHH and ARC/ARG3. 1 in brain neurons of neonatal rats exposed to thyroid dysfunction in uterus. Methods Wistar pregnant rats were randomly divided into control group and experimental groups that rats were drunk water with 1, 3, or 5 ppm propylthiouracil ( PTU). The thyroid function and morphological changes of PND1 and PND7 were detected. The expression of MCT8, DCX, SHH, ARC/ARG3. 1 protein in cerebral cortex and hippocampus were detected by Western blot or immunohistochemistry. Results (1) The levels of TT4 decreased significantly in PND1 pups of PTU 3 ppm and 5 ppm groups (P＜0.05 or P＜0.01). The TSH levels significantly increased while FT4 levels significantly decreased in pups of PTU 5 ppm group on PND7 ( P＜0. 05). ( 2) The number NV, V, S, and cross-sectional area of thyroid follicles in offspring of PTU groups were significantly higher than those in the control group on postnatal day 1 and 7 (P＜0.05 or P＜0.01, respectively). (3) The expression of MCT8 in cortex and hippocampus gradually increased with the increase dose of PTU on two postnatal days, but there was significant change in PTU 5 ppm group on PND1 ( P＜0.05). The expression of SHH in pup cortex decreased with the increase of PTU exposure dose on PND7. DCX protein expression in the pup cortex on two postnatal days showed an uptrend with the increase of PTU exposure dose. ARC/ARG3.1 protein levels in hippocampal CA1 area of the pups increased significantly in PTU 1 ppm group on PND1 than that in the same-day control group ( P＜0. 05). Conclusion The damaged neurons of neonatal rats exposed to hypothyroidism in utero can be improved with the gradual recovery of thyroid function, but can not be completely restored to normal level.