Effects of alcohol on lectin binding affinity in rat gastric mucosa

Fluoresceinated lectins were employed to qualitatively evaluate cell surface carbohydrates, with and without ethanol exposure, in rat stomach mucosae. Rats received 1 ml of saline, or 50% or 100% ethanol orally. After 30 min, tissue samples of the glandular stomach were retrieved, cryosectioned, and incubated with one of a panel of lectins. Another set of sections was preincubated with neuraminidase to remove sialic acid residues. Qualitative evaluation of lectin binding showed that although several different sites stained, concanavalin A was the only lectin to stain the extracellular matrix, and soybean agglutinin the only lectin to stain chief cells. Neuraminidase preincubation enhanced lectin binding to both stained and previously unstained sites. Ethanol, both 50% and 100%, produced changes in both neuraminidase-treated and untreated tissues, increasing the specific binding of concanavalin A, Ulex europaeus agglutinin I, and wheat germ agglutinin, while decreasing Helix pomatia agglutinin and soybean agglutinin. These results suggest that ethanol can, through unknown mechanisms, alter carbohydrate binding affinity.