Vitamin C improving effect on learning and memory impairment induced by hypothyroidism during neonatal and juvenile growth in rats: role of oxidative stress

Introduction & Objective: In this study effects of Vitamin C (Vit C) on hypothyroidism-associated learning and memory impairment during neonatal and juvenile growth in rats was investigated.Method: Fifteen pregnant rats were kept in separate cages and after delivery randomly divided into five groups and treated as follows: (۱) Control (normal drinking water); (۲) propylthiouracil (PTU ۰.۰۰۵%); (۳-۵) PTU-Vit C ۱۰, ۱۰۰ & ۵۰۰ received PTU ۰.۰۰۵% and ۱۰, ۱۰۰ and ۵۰۰ mg/kg Vit C from the first day after birth through the first ۸ weeks of life of offspring. ۱۰ male offsprings of each group were randomly selected and tested in the Morris water maze (MWM) and passive avoidance (PA). Brains were removed for biochemical measurements.Results: PTU increased time latency and reduced time spent in target quadrant in MWM and decreased latency for entering to the dark compartment in PA. PTU reduced serum thyroxine and thiol groups, superoxide dismutase (SOD) and catalase (CAT) activities in brain and increased hippocampal molondialdehyde (MDA). In MWM test, ۱۰۰ and ۵۰۰ mg/kg Vit C reduced time latency and traveled distance and all doses of Vit C increased the spent time and traveled distance in target quadrant, while increased the time latency for entering to the dark compartment in PA. Vit C increased serum thyroxine, thiol, SOD and CAT in the brain tissues while reduced MDA.conclusion: Results demonstrated Vit C has protective effects on hypothyroidism-associated learning and memory impairment during neonatal and juvenile growth in rats that it might be due to the antioxidative effects of Vit C.

Keywords:

Vitamin C , Hypothyroidism , Memory , Oxidative stress