[Induction of bacterial translocation in rats with minimal doses of endotoxin].

OBJECTIVE

To determine whether a non lethal dose of intramuscular endotoxin in rats causes a physical disruption of the mucosal barrier and promotes the translocation of bacteria from gut to visceral organs.

DESIGN

Prospective randomized trial.

SETTING

Experimental laboratory university medical center.

EXPERIMENTS

60 male wistar rats, weighing 250 g.

INTERVENTIONS

six hours and twenty-four hours after endotoxin (8 mg/kg) or saline (control group) given intramuscularly, rats were sacrificed and mesenteric lymph nodes, spleen and some segments of the ileum were removed. Lymph nodes and spleen were cultured for translocating bacteria while ileum segments were observed by light microscopy.

RESULTS

Incidence of bacterial translocation increases from 6 hours (40% p < 0.05) to 24 hours (60%, p < 0.01) after endotoxin administration. Histologic evaluation of the ileum demonstrated that a mucosal injury occurred only at the 24 an hour and that it was characterized by an evident pronounced interstitial edema with focal breaks in the basal membranes of villous and glands.

CONCLUSIONS

It appears that microorganisms and microbial products contained in the gut can cross the mucosal barrier and spread into other visceral organs also after a low dose of intramuscular endotoxin.