Assessing empathy like social behavior in valproic acid induced autism model of rats

Autism Spectrum Disorders are neurodevelopmental disorders with repetitive behaviors, social interaction and communication deficits which have genetic and environmental roots. Prenatal VPA exposure increases autism risk in humans and used in experimental models. Wistar Albino pregnant females received either 400mg/kg/ml VPA (n=3) or same volume of saline (n=2) i.p. on embryonic day 12.5. On postnatal day 20 (P20) rats were separated from mother and testing began on P22 (nVPA=26, ncontrol=23). Rats were tested for empathy on P30 and P60 in a 25x60x30cm Plexiglas box and restrainer. Restrained sibling rat was placed at the centre of the box and subject rat's behavior was recorded for 10 minutes. Subject rats were not trained before test and were not given any reinforcements. Besides testing for empathy, rats were assessed for malformations and tested for olfactory discrimination, social performance, pre- pulse inhibition and locomotor activity. To assess empathy, attentive time of subject rat with sibling and subject's frequency of attempt to open restrainer's door were measured. VPA group spent less attentive time with sibling on P30 and P60 compared to controls (p<0,05; p<0,001). Although there were no differences between groups on P30 for frequency of attempt to open restrainer's door, VPA group scored less on P60 (p<0,001). For the first time in literature assessment of empathy in autism models has been showed. Other tests' results confirm autism like symptomatic effects of prenatal VPA exposure. Our study shows VPA's effects on neurologic and social development.