Assessment of empathy-like behaviour in valproic acid-induced rat model of autism

Abstract

Prenatal VPA exposure is used to model ASD-like symptoms. Disrupted empathy is frequently observed in individuals with ASD, but empathy-like behaviour is not well documented in animal models. Pregnant Wistar Albino rats were administered either 400 mg/kg VPA or saline i.p. on E12.5. Empathy-like behaviour was assessed at P30 and P60 in both female and male offspring, who were also tested for olfactory discrimination, sociability, locomotor activity, and pre-pulse inhibition. Prenatal exposure to VPA significantly impaired empathy-like behaviour, as measured by the duration of time the subject spent with its sibling and the frequency of attempts to open the restrainer door. When P30 and P60 results were compared within groups, a developmental arrest in empathy-like behaviour was observed in the VPA group, whereas the control group showed improvement in their scores. Prenatal exposure to VPA also resulted in significantly decreased sociability and pre-pulse inhibition rates. In this study, an adapted version for measuring empathy-like behaviour has been proposed. This version involved a restrained sibling and no prior training, allowing the measurement to be independent of learning, memory, and stranger anxiety. The results show that VPA has negative effects on social development and is a valid tool for modelling ASD in both females and males.