The effect of endotoxin on intestinal mucosal permeability to bacteria in vitro
L. L. Go, P. J. Healey, S. C. Watkins, R. L. Simmons and M. I. Rowe
Department of Pediatric Surgery, Children's Hospital of Pittsburgh, Pa.
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. CONCLUSIONS: Increased
permeability to bacteria at the mucosal level contributes to the bacterial
translocation seen in endotoxemia.
