BACTERIAL LIPOPOLYSACCHARIDE REDUCED INTESTINAL BARRIER FUNCTION AND ALTERED LOCALIZATION OF 7H6 ANTIGEN IN IEC-6 RAT INTESTINAL CRYPT CELLS

The intestinal epithelial barrier restricts the passage of potentially toxic substances into the systemic circulation and is considered to b e mostly mediated by tight junctions, though the mechanisms involved i n the regulation of intestinal tight junctions are not yet fully under stood. In the present study, we examined whether bacterial lipopolysac charide (LPS) altered the barrier function of tight junction and local ization of tight junctional proteins, ZO-1 and 7H6 antigen, in IEC-6 i ntestinal cells. Administration of LPS to the basolateral surface of I EC-6 cells disrupted the barrier function and caused the disappearance of 7H6 antigen from the cell border, whereas LPS administered to the apical surface altered neither the barrier function nor the localizati on of 7H6 antigen in IEC-6 cells. On the other hand, the localization of ZO-1 was not influenced by these treatments of LPS. These results s uggest that the interaction of LPS with the basolateral surface of int estinal epithelial cells disrupts the barrier function and 7H6 antigen take part in the maintenance of the barrier function in IEC-6 cells. (C) 1997 Wiley-Liss, Inc.