Alpha-tocopherol and gamma-tocopherol attenuate ethanol-induced changes in membrane fatty acid composition in embryonic chick brains

BACKGROUND: This project investigated whether or not EtOH-induced reductions in the levels of long-chain polyunsaturated membrane fatty acids could be attenuated by exogenous exposure to either alpha-tocopherol, gamma-tocopherol, or diallyl sulfide (DAS). METHODS: At 0 days of development, fertile chicken eggs were injected with a single dose of either saline supplemented with various concentrations of EtOH, alpha- or gamma-tocopherol and EtOH, or DAS and EtOH. At 18 days of development, brains were isolated and subjected to membrane analyses. RESULTS: When exposed to EtOH, concentrations ranging from 0-60.50 microm/Kg egg, dose-dependent decreases in the levels of brain 18:0, 18:1 (n-9), 18:2 (n-6), 18:3 (n-3), and 20:4 (n-6) were observed. These ethanol-induced changes in membrane fatty acid composition correlated with ethanol-induced reductions in brain mass, brain protein levels, acetylcholine esterase (AChE) activities and correlated with increased lipid hydroperoxide levels. Exposure to either 2.5 microm alpha-tocopherol/Kg egg and 6.050 mm EtOH/Kg egg, or 2.5 microm alpha-tocopherol/ Kg egg and 6.050 mm EtOH/Kg egg attenuated EtOH-induced changes in membrane fatty acid composition, brain mass, brain protein levels, AChE activities, and lipid hydroperoxide levels. Embryonic exposure to the cytochrome p450-2E1 inhibitor, diallyl sulfide (DAS), also attenuated EtOH-induced decreases in long-chain, unsaturated membrane fatty acids. However, embryonic exposure to DAS promoted abnormally low brain mass. CONCLUSION: EtOH-induced reductions in the levels of brain long-chain polyunsaturated fatty acid are caused by lipid peroxidation.