Sexual aggression and prenatal stress lead to poor maternal care and aggressive behaviour in male Wistar rat offspring

Sexual aggression and prenatal stress can exert profound intergenerational effects, disrupting maternal care and enhancing aggression in offspring via alterations to the hypothalamic-pituitary-adrenal (HPA) axis and related neurochemical systems. This study in Wistar rats examined the combined impact of male sexual aggression and prenatal stress on maternal caregiving behaviours, and the neurobiological mechanisms underlying sexually aggressive behaviours in male offspring (F1). Following exposure to sexual aggression, females were mated with group-housed or isolated males and assigned to prenatal stress or control conditions. Maternal care was quantified from postnatal day (PND) 2-8, while F1 male aggression was assessed in resident-intruder and sexual aggression paradigms. Neurochemical analyses measured arginine vasopressin (AVP), corticotropin-releasing hormone (CRH), serotonin, oxytocin, corticosterone, and neurokinin B in the prefrontal cortex, hippocampus, amygdala, and hypothalamus, alongside gene expression profiling. Prenatal stress significantly reduced maternal care-particularly nursing and licking-across PND 2-8, with deficits most pronounced when paired with paternal isolation. High-quality maternal care was associated with reduced F1 aggression, longer attack latencies, and lower CRHR1 expression in the hippocampus, suggesting a neuroprotective role. Prenatal stress increased CRHR1 expression in the amygdala and amplified aggression, anxiety-like behaviours, and reduced sociability. Serotonin correlated negatively with aggression and positively with non-social exploration, while corticosterone correlated positively with aggression. Oxytocin was linked to social behaviours, and CRH to exploratory behaviours, indicating distinct neuromodulatory pathways. These findings highlight the interactive effects of maternal and paternal environments on intergenerational behavioural programming and identify key neurochemical targets for mitigating stress-related aggression.