Polyunsaturated Omega-3 fatty acids restore reduced social interaction and dopaminergic activity in the prefrontal cortex of cow's milk allergic mice

Background: The dopaminergic system in the prefrontal cortex (PFC) is known to modulate attentional skills, perception and social behavior. Decreased levels of dopamine (DA) in the PFC are implicated to be involved in various psychiatric diseases. Furthermore, disturbed levels of polyunsaturated fatty acids (PUFA) in blood have been observed in these disorders and literature suggests a potential beneficial role for dietary intervention with PUFA as well. In this study, we investigated the effect of n-3 PUFA on altered social behavior of cow's milk allergic (CMA) mice and corresponding DA levels in the PFC. Method: Male C3H/HeOuJ mice were orally sensitised with whey protein and cholera toxin (CT) or CT alone, once a week for 5 weeks and subsequently orally challenged with whey protein once. Starting two weeks before first sensitisation, mice were kept on an omega-3 PUFA diet or control diet. The morning after challenge, a social behaviour test was performed, mice were sacrificed and brains were collected. PFC was isolated and dopamine levels were determined by using HPLC. Results: Cow's milk allergy in mice caused reduced social interaction and a dietary intervention with n-3 PUFA significantly improved social behavior in allergic mice. Furthermore, dopamine and metabolite levels in the prefrontal cortex were significantly reduced in cow's milk allergic mice. When allergic mice were fed an n-3 PUFA diet, both dopamine and metabolite levels were restored to those found in non-allergic mice. Conclusion: n-3 PUFA possibly exerts its beneficial effect on behavior via modulating the dopaminergic system in the prefrontal cortex and might offer a dietary intervention in some psychiatric disorders. This study is part of the Utrecht University 'Focus en Massa' program and is financially supported by Danone Research- Centre for Specialised Nutrition.