n-3 PUFAs have beneficial effects onanxiety and cognition in female rats: Effectsof early life stress

Stressful life events, especially those in early life, can exert long-lasting changesin the brain, increasing vulnerability to mental illness especially in females. Omega-3 polyun-saturated fatty acids (n-3 PUFAs) play a critical role in the development and function of thecentral nervous system (CNS). Thus, we investigated the influence of an eicosapentaenoic acid(EPA)/docosahexaenoic acid (DHA) (80% EPA, 20% DHA) n-3 PUFAs mixture on stress-relatedbehavioural and neurobiological responses.Sprague-Dawley female rats were subjected to an early-life stress, maternal separation (MS)procedure from postnatal days 2 to 12. Non-separated (NS) and MS rats were administeredsaline, EPA/DHA 0.4 g/kg/day or EPA/DHA 1 g/kg/day, respectively. In adulthood, EPA/DHAtreated animals had a dose dependent reduction in anxiety in NS rats. Furthermore, cognitiveperformance in the novel object recognition task (NOR) was improved by EPA/DHA treatmentin NS animals only. EPA/DHA 1 g/kg/day decreased behavioural despair in the forced swim test. Notably, EPA/DHA high dose increased the translocation of GRs into the nucleus of NS rat hip-pocampus. However, the levels of mBDNF remained unchanged in all the experimental groups. The corticosterone response to an acute stress was blunted in MS rats and this was further attenu-ated by pre-treatment with EPA/DHA. Immune response and monoamine neurotransmission weresignificantly altered by early-life stress. In conclusion, our study supports the view that n-3 PUFAsare beneficial in neurodevelopmentally normal animals but have little positive benefit in animalsexposed to early life stress.