Effects of vitamin A on endotoxaemia in rats.

OBJECTIVES

To find out if survival after peritonitis induced by caecal puncture and injection of endotoxin is correlated with serum endotoxin concentrations in rats; whether this study could be carried out by studying the effects of vitamin A in rats with peritonitis; and if it was possible to differentiate between local and systemic effects of vitamin A on endotoxaemia in rats.

DESIGN

Prospective randomised study.

MATERIAL

Sixty adult male Sprague-Dawley rats.

INTERVENTIONS

Rats were kept on a diet containing no vitamin A for six days; 30 were given vitamin A 1,380 IU/kg/day intramuscularly and 30 were given peanut oil. Peritonitis was then induced in 16 rats by caecal puncture (treated n = 10, untreated n = 6) and the remainder received intraperitoneal injections of either 0.5 mg/kg endotoxin, or 2.0 mg/kg endotoxin.

MAIN OUTCOME MEASURES

Plasma concentrations of vitamin A, vitamin E, and serum concentrations of endotoxin, estimation of erythrocyte volume fraction and leucocyte particle concentrations, and survival.

RESULTS

Rats that were given 2 mg of endotoxin had higher mortality and did generally less well than others. Serum endotoxin concentrations were lower in those groups that had been pretreated with vitamin A. No animal developed vitamin A deficiency and there were no differences in erythrocyte volume fraction or leucocyte particle concentration between those that did and did not receive vitamin A.

CONCLUSION

Vitamin A lowered the concentration of endotoxin in the circulation, it has a central function in the host's defence against endotoxin, and the experimental model seems suitable for the study of the effect of vitamin A or endotoxemia and peritonitis.