Bile mediates intestinal pathology in endotoxemia in rats

Intestinal pathology frequently accompanies experimental endotoxic shock and is mediated by proinflammatory cytokines. Our hypotheses are that hepatobiliary factors operating from the luminal side of the gut make a major contribution to this damage and that tumor necrosis factor alpha (TNF-alpha) is involved in the pathology. We treated rats with lipopolysaccharide (LPS) intravenously and found that external drainage of bile totally protected the gastrointestinal tract, macroscopically and microscopically, 4 h after LPS administration and dramatically improved survival of the animals for 48 h after LPS administration. The concentration of TNF-alpha in bile increased markedly after LPS administration and was over 30 times higher in bile than in serum. Tissue damage and the biliary TNF-alpha response were abrogated when animals were pretreated with gadolinium chloride to eliminate Kupffer cells. TNF-alpha infusion into the duodenal lumen caused intestinal damage similar to that elicited by intravenous LPS. In rats treated with LPS, survival was significantly increased during the first 36 h in animals given an infusion of anti-TNF-alpha antibody into the duodenum. These results demonstrate that in endotoxemia, intestinal damage is mediated by factors derived from the bile. The findings indicate that luminally acting TNF-alpha contributes to the intestinal damage.