Short-term exposure to alcohol increases the permeability of human oral mucosa

OBJECTIVES: The aim of this study was to evaluate the effect of short-term exposure to ethanol on the permeability barrier properties of human oral mucosa. MATERIALS AND METHODS: Permeability constants (K-P x 10(-4) cm min(-1)) to tritiated water were determined, for untreated human ventral tongue, and following treatment with phosphate-buffered saline (PBS), 5, 15 or 40% ethanol using an in vitro perfusion chamber system. Some samples were also exposed to fluorescent-labelled albumin and examined by fluorescence microscopy. Permeability barrier lipid composition was assessed in treated and untreated mucosa by heat separation, solvent extraction and thin layer chromatography. RESULTS: Fifteen per cent ethanol significantly increased mucosal permeability (5.8 +/- 0.44; P < 0.05) compared with untreated, PBS and 5% ethanol treated mucosa (4.69 +/- 0.26, 4.48 +/- 0.3 and 4.13 +/- 0.27, respectively). Albumin was restricted to the epithelial surface in control tissue, but extended further through the epithelium and, in some cases, into the connective tissue after treatment with ethanol. Biochemical analysis revealed no significant difference in the epithelial lipid composition of treated and untreated mucosa. CONCLUSIONS: These results suggest that short-term exposure to ethanol may act as a permeability enhancer, possibly by causing molecular rearrangement of the permeability barrier, not as a result of lipid extraction.