Neurobehavioural Effects of Prenatal Sodium Valproate Exposure in Rat Offspring

Pregnant rats were administered sodium valproate (12.5, 25 and 50 mg/kg/day) orally once daily during the gestation days 13 to 20. Maternal sodium valproate treatment produced a dose dependent significant reduction in litter size at birth and reduced body growth during postnatal days. Sodium valproate treatment had no significant effect on maternal weight gain during pregnancy and pups mortality during postnatal period. The pups born were subjected to open-field exploratory behaviour and elevated plus maze tests of anxiety at 8 and 9 weeks of age. Prenatal sodium valproate treatment (12.5, 25 and 50 mg/kg/day) induced significant increase in open-field ambulation, rearings and self-grooming in rat offspring. Prenatal sodium valproate treated rat offspring displayed significantly increased anxiogenic behaviour on elevated plus maze (spent less time on open arms, more time on enclosed arms and made fewer number of entries on open arms) comparison to control rat offspring. The results suggest that prenatal sodium valproate exposure induces neurobehavioural toxicity and indicate persistent behavioural alterations in the rat offspring.