ADAPTATION OF GASTRIC-MUCOSA TO CHRONIC ALCOHOL ADMINISTRATION IS ASSOCIATED WITH INCREASED MUCOSAL EXPRESSION OF GROWTH-FACTORS AND THEIR RECEPTOR

In our previous study we found that chronic, intragastric administration of ethanol to rats produces adaptation of the gastric mucosa to subsequent challenge with an acute dose of 50% ethanol. The mechanism of this mucosal tolerance remains unexplained. Epidermal growth factor (EGF) and transforming growth factor alpha (TGFalpha) stimulate cells growth and proliferation in the gastric mucosa with noted trophic effect, protect the gastric mucosa against acute injury and accelerate healing of injured mucosa. Many of these effects are exerted through EGF and TGFalpha action on their common receptor (EGFR). The aim of the present study was to determine the effect of chronic alcohol administration on cell proliferation and gastric mucosal expression and distribution of EGF, TGFalpha and EGFR. Chronic administration of ethanol (1 ml, 50% ethanol, twice daily) significantly increased the extent of gastric mucosal mucous and proliferative cell zones, the number of proliferating (DNA synthesizing) cells and mucosal expression of EGF, TGFalpha and EGFR by 13, 6, and 20-fold, respectively. Thus, adaptation of gastric mucosa to chronic alcohol administration is associated with increased cell proliferation and increased expression of mucosal EGF, TGFalpha and EGFR.