Effect of experimentally induced hypothyroidism during gestation period on activity dependent neurotrophic factor (ADNF) in newborn rat brain tissue.

Purpose The aim of the study was to evaluate the effects of prenatal hypothyroidism on neonatal rats by the way of activity-dependent neuroprotective factor (ADNF) expression. Methods Twenty-one Wistar albino neonatal rats were divided into two subgroups; a control group and neonatal rats with experimental maternal hypothyroidism. Hypothyroidism was induced by using propylthiouracil (PTU). Neonatal rats obtained PTU from breast milk continuously for 1 week after birth. The rats from the control group were fed only normal feed and water. After birth, body weight and blood thyroid hormone levels were tested. Glial fibrillary acidic protein (GFAP), Slug, Numb, Notch-1 and ADNF antibodies were used for immunohistochemical analysis. Real-time polymerase chain reaction (RT-PCR) and Western blotting analyses were used to evaluate ADNF gene expression levels from 1-week-old rat's brain. Results There was no difference between the two groups for birth weights. The thyroxine (T4) level from the experimental group was <0.4 ng/mL, and it was 0.8 ng/mL for the control group. It was shown that, the results from the experimental group samples had significantly lower ADNF mRNA levels than control group (p < 0.05). The increase from GFAP and Numb expression and decrease from Slug expression were shown in the experimental group. Local differences were identified for ADNF and a decrease was shown in both sides of brain. There was no difference for Notch-1 expression for both groups. Conclusion In this study, decreasing ADNF expression might contribute to developing neurological problems in congenital hypothyroidism.