Efeitos da suplementação com Ômega 3 sobre comportamentos relacionados à depressão em camundongos adultos expostos a estresse crônico

Abstract

The characteristics of depression, in a general way, are sadness ou irritability, somatic and cognitive changes that generate huge prejudices to the global action capacity of the individual, alternating affection and neurovegetative functions. It’s not yet known the specific causes of the depressive disorder, although some researches point to a multifunctional physiopathology, hypothalamic and neurotransmission disorder. A possibility is that it occurs some disturbs in the monoaminergic transmission, reducing serotonin neurotransmission (5-HT), norepinephrine (NE) and dopamine (DA). In relation to dopamine neurotransmission, researches point that omega-3 supplementation (ω-3) on rats diet generates a 40% increase on the DA levels in the frontal cortex, such as on the DA receptor connection, which is appropriate to the dopaminergic system and behavior performance on animal adult age. Depression is also associated to high cortisol levels on the blood due to hypothalamic-pituitary-adrenal (HPA) axis malfunction. The eicosapentaenoic acid found on ω-3 can regulate the HPA axis, reducing the corticotropin (CRF) liberating hormone and the cortisol secretion. These factors demonstrate the possible antidrepressive action, modulating the oxidative reactions and the inflammatory cytokines production on the microglia and neuronal cells. In this way, this project had the objective of evaluating the effects of chronic stress by the restriction of movement, as well as the Omega 3 supplementation, being 10 microliters by animal, under the depression related behavior, studied by the behavior of Forced Swimming test. During 15 days, the animals (Balb C mouse), were divided in 4 groups: the first group received H2O, the second received ω-3, the third received H2O + stress (ES) and the fourth received ω-3 + ES. The stress was generated by movement restriction protocol that lasted 2 hours and received ω-3 or water, administrated by gavage twice by day. On the Forced Swimming test there were no significant differences between groups, although they were treated by ω-3 and the ones who weren’t exposed to stress has presented the fastest immobility time, suggesting a possible neuroprotector effect. On the used protocol in our experiments, the stress by restriction of movement hasn’t increased the behaviors related to depression and the ω-3 on the used dose, hasn’t presented neuroprotection.