Effects of Rat Prenatal Exposure to Valproic Acid on Behaviour and Neuro-Anatomy

Autism is a highly debilitating disorder that has recently displayed a dramatic rise in incidence. In order to realistically study preventative and remedial strategies, it is important that we develop and understand useful animal models of the disorder. The purpose of this study was to investigate the efficacy of the prenatal valproic acid (VPA) rat model of autism by examining the neuro-anatomical and behavioural outcomes of offspring exposed to this paradigm. The VPA-treated rats exhibited behavioural changes in the delayed nonmatch-to-sample task, novel object recognition, activity box, and Whishaw tray reaching task. Anatomically, there was a reduction in brain weight and cortical thickness, along with decreased dendritic branching in the orbitofrontal cortex (OFC) and medial prefrontal cortex (mPFC), and decreased spine density in the mPFC, OFC, and cerebellum. Behavioural and anatomical findings from this study produced reliable results indicating that prenatal VPA exposure may be a viable model for the study of autism in rats. Copyright (c) 2012 S. Karger AG, Basel