Vitamin A deficiency impairs colonic healing but not adhesion formation in germ-free and conventional rats

Vitamin A is well recognized as a factor of major importance in epithelial and connective tissue repair mechanisms. Recently it was shown that vitamin A deficiency caused overgrowth and translocation of intestinal bacteria in rats. The aim of this study was to investigate the healing of colonic anastomoses and formation of postsurgical adhesions in vitamin A-deficient germ-free and conventional rats. Fourteen germ-free and 10 conventional rats were allocated to four groups: germ-free rats not given vitamin A, germ-free rats given vitamin A, conventional rats not given vitamin A, and conventional rats given vitamin A. All rats underwent surgery for colonic anastomosis. Seven days afterward, they were euthanized, and the bursting pressure of colonic anastomosis and formation of peritoneal adhesions were evaluated. The bursting pressures in groups not given vitamin A were lower than in groups given vitamin A. The adhesion scores in germ-free groups were lower than in conventional groups. These findings demonstrated that vitamin A had an important role in healing of colonic anastomoses whether in the presence or absence of intestinal flora, and that intestinal bacteria had a greater effect than vitamin A on formation of postsurgical adhesions. This may suggest that the mechanism of healing of colonic anastomoses differs from that of postsurgical adhesion formation.