Lipopolysaccharide-induced gastrointestinal injury in rats: Role of surface hydrophobicity and bile salts

Sepsis of gastrointestinal origin can lead to life-threatening complications in vital organs due to bacterial overgrowth and/or translocation from the lumen into the blood. In a rat model of endotoxemia, changes in surface hydrophobicity (associated with barrier integrity) of the gastrointestinal mucosa were examined. Rats were treated with Escherichia coli lipopolysaccharide (LIPS), and gastric and ileal tissue were collected for determination of surface hydrophobicity by contact angle analysis. A role for bile salts in hydrophobicity changes was tested by quantifying bile salts in the lumen of both the stomach and ileum after LPS and by the administration of LIPS to bile duct-ligated rats. A single intraperitoneal dose of LPS induced a dose- and time-dependent reduction in hydrophobicity of both the stomach and ileum, with the stomach showing greater sensitivity at an earlier time than the ileum. LIPS also induced gastric bleeding, reflux of bile acid into the gastric lumen, and decreased levels of bile salt in the ileum. The LPS-induced reductions in surface hydrophobicity of the stomach were prevented by prior bile duct ligation. We conclude that LPS disrupts gastrointestinal barrier integrity, in part by mechanisms involving bile constituents and an attenuation in the mucosa's hydrophobic characteristics.