January 1995

The Effect of Endotoxin on Intestinal Mucosal Permeability to Bacteria In Vitro

Author Affiliations

From the Department of Pediatric Surgery, Children's Hospital of Pittsburgh (Pa), (Drs Go, Healey, and Rowe); The Center for Structural Imaging, Pittsburgh (Dr Watkins); and the Departments of Neurobiology (Dr Watkins) and Surgery (Dr Simmons), University of Pittsburgh School of Medicine. Dr Go is currently affiliated with the Department of Surgery, Medical College of Wisconsin, Milwaukee.

Arch Surg. 1995;130(1):53-58. doi:10.1001/archsurg.1995.01430010055011

Objective:  To examine the role of the intestinal mucosa in bacterial translocation, in vitro bacterial passage across ileal mucosal segments mounted in Ussing chambers were studied in control and endotoxin (lipopolysaccharide)-treated rats.

Design:  Experimental study.

Materials and Methods:  Three groups of rats were studied. The experimental group received an intraperitoneal injection of lipopolysaccharide, while controls received an equivalent volume of saline solution; a third group received no treatment. Twenty-four hours later, all groups underwent laparotomy and organ culture to assess bacterial translocation. At the same time, a segment of mucosa from the terminal ileum of each animal was mounted in a Ussing chamber, and the transmucosal passage of labeled Escherichia coli from the luminal to serosal surface was assessed by results of serial cultures.

Results:  In vivo bacterial translocation occurred in 100% of the lipopolysaccharide-treated animals, significantly higher than the incidence seen in controls (25%; P<.05). In vitro passage of labeled E coli across ileal mucosa in the Ussing chamber occurred in 78% of lipopolysaccharide-treated animals, while in controls transmucosal passage was seen in only 14% (P<.05). Histologic examination of mucosa from both groups using light and transmission electron microscopy demonstrated no structural differences between groups.

Conclusion:  Increased permeability to bacteria at the mucosal level contributes to the bacterial translocation seen in endotoxemia.(Arch Surg. 1995;130:53-58)