Ethanol drinking, brain mitochondrial DNA, polyunsaturated fatty acids and effects of dietary anthocyanins

This study aimed at exploring whether moderate ethanol drinking may have adverse effects on the fatty acids composition and on mitochondrial DNA (mtDNA) of rat brain. A secondary aim was to examine whether dietary antioxidant anthocyanins (ACN) can be protective. One group of rats received ethanol 12% and another water as an exclusive liquid to drink for 8 weeks. In order to test the impact of ACN consumption, two other groups of rats were fed an ACN-rich diet in combination with either ethanol or water. Brain fatty acids were measured by gas chromatography and mtDNA alterations, markers of mitochondrial suffering, were studied through an original real-time qPCR-based protocol. Linoleic acid (LA, 18:2n-6) and eicosadienoic acid (20:2n-6) were significantly decreased, by 12% and 31% respectively, in the brains of both ethanol groups. The other brain lipids, including arachidonic acid (20:4n-6) and n-3 polyunsaturated fatty acids, were not modified. These changes were associated with a significant increase in deleted mtDNA (by 28%) in the ethanol group, without total mtDNA depletion. The ACN-rich diet prevented the increase in mtDNA common deletion (mtDNA CD). These data demonstrate that moderate ethanol drinking reduces certain brain n-6 and results in mtDNA injury. The antioxidant anthocyanins protect brain mtDNA but do not restore normal n-6 levels. Further studies are required to investigate the consequences of a decrease in n-6 levels in brain.