Red Wine, but not port wine, protects rat hippocampal dentate gyrus against ethanol-induced neuronal damage--relevance of the sugar content.

AIMS Chronic ethanol consumption leads to oxidative damage in the central nervous system inducing neuronal degeneration and impairment of brain functions. Nevertheless, it has been reported that grape polyphenols might prevent the alluded ethanol effects. We have reported that prolonged red wine intake improves hippocampal formation oxidative status, a finding not replicated using Port wine. Thus, we thought of interest to compare the effects of chronic ingestion of these wines in the morphology of dentate gyrus (DG) neurons that are particularly vulnerable to alcohol effects. METHODS Six-month-old Wistar rats were fed either with red wine or Port wine (both with 20% ethanol content, v/v), and the results were compared with 20% (v/v) ethanol-treated, ethanol/glucose and pair-fed control groups. After 6 months of treatment, the layer volumes of the DG and the total number of granule and hilar neurons were estimated. The dendritic trees of granule cells were also studied in Golgi-impregnated material. RESULTS The number of granule cells and the DG layer volumes were similar among all groups. However, the number of hilar neurons was reduced in Port wine, ethanol-treated and ethanol/glucose animals. Furthermore, the granule cells from these groups showed a decrease in the total dendritic length. CONCLUSIONS Although the Port wine and red wine have similar amounts of flavanols with identical ability to protect against oxidative stress, the differences observed are probably related to the very dissimilar processes of wine production, leading in Port wine to a high content of sugars, which are known to have potent pro-oxidant effects.