Brain derived neurotrophic factor and oxidative stress index in pups with developmental hypothyroidism: neuroprotective effects of selenium.

Thyroid hormones (THs) are crucial for growth and development and particularly brain development. The present study was carried out to investigate the brain derived neurotrophic factor (BDNF) and Oxidative stress index (OSI) in the brain of pups born to dams with methimazole (MMI) induced hypothyroidism. Also, to elucidate the effectiveness of selenium (Se) in ameliorating the brain damaging effects induced by maternal hypothyroidism. Our results reveled that plasma free T3 (FT3), free T4 (FT4), growth hormone (GH) were significantly decreased while plasma thyroid stimulating hormone (TSH) was significantly increased in the pups. BDNF level significantly decreased while OSI significantly increased in both the hippocampus and cerebellum in pups born to hypothyroid dams. Se supplementation significantly alleviated the levels of these parameters. The biochemical modifications were confirmed histologically with the abnormal development of the hippocampus and cerebellum and partial reversal of these effects with Se supplementation. We concluded that reduced hippocampal and cerebellar BDNF levels and increment of oxidative stress during early development may contribute to the adverse neurodevelopmental effects of hypothyroidism during pregnancy. Also, Se is an important neuroprotective element that may be used as a dietary supplement against brain damage induced by hypothyroidism.