Effects of omega-3 on behavioral and biochemical parameters in rats submitted to chronic mild stress.

Major depression is a heterogeneous psychiatric disorder whose pathophysiology is not clearly established yet. Some studies have shown that oxidative stress and mitochondrial dysfunction are involved in the development of major depression. Since most depressed patients do not achieve complete remission of symptoms, new therapeutic alternatives are needed and omega-3 has been highlighted in this scenario. Therefore, we have investigated the effects of omega-3 on behavioral and biochemical parameters in rats submitted to chronic mild stress (CMS). Male Wistar rats were submitted to CMS for 40 days. After the CMS period, we administered a 500 mg/kg dose of omega-3 orally, once a day, for 7 days. The animals submitted to CMS presented anhedonia, had no significant weight gain, presented increased levels of lipid peroxidation and protein carbonylation, and inhibition of complex I and IV activities of the mitochondrial respiratory chain. The treatment with omega-3 did not reverse anhedonia; however, it reversed weight change, increased lipid peroxidation and protein carbonylation levels, and partially reversed the inhibition of mitochondrial respiratory chain complexes. The findings support studies that state that major depression is associated with mitochondrial dysfunction and oxidative stress, and that omega-3 supplementation could reverse some of these changes, probably due to its antioxidant properties.

ω-3 and major depression: a review.

BACKGROUND: The World Health Organization estimates that major depression affects about 350 million people all over the world and reports this disorder as the major contributor to the global burden of diseases. Despite the well-defined symptomatology, major depression is a heterogeneous psychiatric disorder whose pathophysiology is not clearly established. Although several treatments are available, most depressed patients do not achieve the complete remission of symptoms. Factors linked to the persistence of the disorder have been investigated, particularly those related to the way of life. Moreover, it has been suggested that nutritional aspects may influence its development. Among them, a diet rich in ω-3 has been associated with a reduced risk of major depression, although its deficiency is associated with depressive disorders. METHODS: This review provides a general view about evidences of the use of ω-3 in major depression cases. RESULTS: Several studies have demonstrated beneficial effects of ω-3 in the prevention and treatment of major depression. However, not all the results have shown significant statistical benefits. CONCLUSIONS: More studies are necessary to clarify detailed mechanisms of the antidepressant effects of ω-3 and may explain the source of contradictions in results published until the moment.

Manual Therapy Reduces Pain Behavior and Oxidative Stress in a Murine Model of Complex Regional Pain Syndrome Type I.

Complex regional pain syndrome type I (CRPS-I) is a chronic painful condition. We investigated whether manual therapy (MT), in a chronic post-ischemia pain (CPIP) model, is capable of reducing pain behavior and oxidative stress. Male Swiss mice were subjected to ischemia-reperfusion (IR) to mimic CRPS-I. Animals received ankle joint mobilization 48h after the IR procedure, and response to mechanical stimuli was evaluated. For biochemical analyses, mitochondrial function as well as oxidative stress thiobarbituric acid reactive substances (TBARS), protein carbonyls, antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) levels were determined. IR induced mechanical hyperalgesia which was subsequently reduced by acute MT treatment. The concentrations of oxidative stress parameters were increased following IR with MT treatment preventing these increases in malondialdehyde (MDA) and carbonyls protein. IR diminished the levels of SOD and CAT activity and MT treatment prevented this decrease in CAT but not in SOD activity. IR also diminished mitochondrial complex activity, and MT treatment was ineffective in preventing this decrease. In conclusion, repeated sessions of MT resulted in antihyperalgesic effects mediated, at least partially, through the prevention of an increase of MDA and protein carbonyls levels and an improvement in the antioxidant defense system.