QS411. Laparotomy Attenuates Lipopolysaccharide Induced Duodenogastric Bile Acid Reflux and Gastric Bleeding

Background: Intra-abdominal infection causes ileus and may require laparotomy for source control. In rats, intraperitoneal lipopolysaccharide (LPS) from E. coli, the most frequent pathogen encountered in these infections, causes duodenogastric bile reflux and gastric bleeding. However, the effects of laparotomy on these endpoints are unknown. It was our hypothesis that laparotomy would exacerbate bile reflux and gastric bleeding from LPS. Methods: Male rats were given either saline or LPS (20 mg/kg ip). One hour later, rats received isoflurane anesthesia with or without laparotomy and were sacrificed 4 hours later. Gastric fluid was analyzed for volume, pH, total hemoglobin content, and bile acid content. Data are mean ± SEM (ANOVA; n ≥ 5). Results: LPS caused significant accumulation of alkaline fluid containing bile and blood when compared to saline treated rats. Laparotomy significantly diminished LPS induced bile reflux and gastric bleeding, but not luminal alkalinization when compared to LPS rats not undergoing laparotomy. Conclusion: These data indicate that laparotomy does not exacerbate the deleterious effects that LPS has on the stomach, but in fact, renders the stomach less susceptible to injury as evident by the reduction in bleeding. Further investigation into the mechanism(s) responsible for these effects are warranted.