Ethanol tolerance: evidence of "protective" effects on brains of adult rats

Previous research with two biochemical markers of acute ethanol damage (sialic acid and 2-deoxyribose) raised the possibility that tolerance developed by chronic ingestion of ethanol could protect brain cells from "damaging" effects of large, acute doses of ethanol. However, this hypothesis required demonstration that chronic consumption was not damaging. This issue was investigated histologically in adult rats that voluntarily consumed massive doses of ethanol daily (range of 11 to 18 gm/kg/rat/day) for 28 days. By all indices (thickness measures of neocortex, hippocampus, and cerebellar molecular layer; and specific cell counts of neocortex and cerebellum), none of the ethanol-exposed rats, even those with intentional nutritional deficiencies, revealed any physical sign of damage compared to control rats.