Mucosal permeability to lipopolysaccharides in the colon in chronic alcoholic rats

摘要

AIMS To evaluate the effects of chronic alcohol abuse on the mucosal permeability to lipopolysaccharide in the colon in rats. METHODS Escherichia coli lipopolysaccharide (LPS, 20 μg/ml) was injected into the colon of chronic alcoholic rats (n = 10) and the rats were supplied with Lieber diets every other day for 6 weeks. Before LPS injection and 5, 10, 20, 30 minutes after injection, blood samples from the portal vein were obtained and contents of LPS in the blood were measured. The distribution of LPS in the colon tissues was observed with a confocal laser scanning microscope by immunofluo-rescent technique using a monoclonal antibody specific to the lipid A region of LPS. Normal rats were used as controls (n = 6). RESULTS Before LPS injection in the colon, LPS levels in the blood of portal vein of chronic alcoholic rats were significantly higher than those of normal controls (3.56 ± 0.67 pg/ml, vs 2.45 ±0.15 pg/ml, P < 0.01). At 5, 10, 20, 30 minutes after injection of LPS, LPS contents were significantly higher than those before LPS injection (173.56 ± 23.45 pg/ml, 154.78 ± 20.57 pg/ml, 43.89 ± 8.67 pg/ml, 45.38 ± 7.89 pg/mls vs 3.56 ± 0.67 pg/ml, P < 0.01 respectively). Most mucosal cells showed strong positive reactions to LPS in the rats of chronic alcohol abuse; but no significant changes of LPS contents in blood from the portal vein and fluorescent reactions to LPS in mucosal cells of normal rats were found after LPS injection. CONCLUSIONS Chronic alcohol abuse resulted in a significant increase of permeability to LPS in colon mucosal cells in rats.