The effects of omega 3 fatty acid supplementation on brain tissue oxidative status in aged wistar rats.

BACKGROUND The omega 3 fatty acids play an important role in many physiological processes. Their effect is well documented in neurodegenerative diseases and inflammatory diseases. Also, aging as a biophysiological process could be influenced by eicosapentanoic acid (EPA) and docosahexanoic acid (DHA) components of fish oil. However there are not many studies showing the effect of PUFA (polyunsaturated FA) suplementation in eldery brain functions and the response to oxidative strees. The aim of this study was to investigate the effects of dietary omega-3 fatty acid supplementation on levels of lipid peroxidation and oxidant/antioxidant status of brain tissue in aged (24 months old) Wistar rats. METHODS Animals were divided in two groups. Control group (n=8) was fed with standard laboratory food and received water ad libitum. Treated group (n=8) was also fed with standard laboratory food, water ad libitum and received fish oil capsules (EPA+DHA) for 6 weeks. Daily dose was 30mg EPA and 45mg DHA (capsules: 200mg EPA and 300mg DHA; in-house method). At the end of treatment animals were sacrificed and brains were collected and frozen on -80ºC. The levels of lipid peroxidation (malondialdehyde - MDA), activity of catalase (CAT) and activity of superoxide dismutase (SOD) were examined in cerebral cortex. Catalase activity was determined by measuring the decrease in absorbance (H2O2 degradation) at 240 nm for 3 min and expressed as U/mg protein. Total SOD (superoxide dismutase) activity was performed at room temperature according to the method of Misra and Fridovich. The extent of lipid peroxidation (LPO) was estimated as the concentration of thiobarbituric acid reactive product malondialdehyde (MDA) by using the method of Aruoma et al. The incorporation of fatty acids in cellular membranes was confirmed by gas chromatography. RESULTS Our results showed that lipid peroxidation significantly decreased in treated animal group, where MDA concentration was 0.38±0.001 vs. 0.43±0.001 nM/ml (p<0.05) in control. However SOD activity increased significantly in treated animal group 1.57±0.24 vs. 4.12±0.15 U/gHb/L (p<0.01) in control. CAT activity decreased in treated group but not significantly. CONCLUSION Incorporation of omega-3 fatty acids after their supplementation had beneficial effects on brain tissue. Omega-3 fatty acids increased activity of SOD and decreased lipid peroxidation. Changes in oxidative/antioxidative balance are a result of EPA and DHA effects on lipids and enzymes of antioxidative system.