1987 Volume 49 Issue 2 Pages 313-321
Escherichia coli inoculated into the uterus under the influence of estradiol causes asymptomatic infection, whereas under the influence of other hormones, it induces purulent endometritis. The present study was undertaken to explain how estradiol prevents E. coli-caused purulent endometritis in rats. Since accumulation of uterine luminal fluid caused by estrogen has been well established, attempts were made to see if it prevents endometritis. Neither retained nor transferred luminal fluid inhibited E. coli from causing purulent endometritis in ovariectomized rats. Then, the relationship between hormone-induced histological changes and uterine susceptibility to E. coli was examined. Mast cells and eosinophils were counted and luminal epithelial cell proliferation and the height of endometrial epithelial cells were examined in rats treated with progesterone and/or estradiol. The luminal epithelial cells were tall when E. coli failed to induce purulent endometritis. It was suggested that estradiol modifies luminal epithelial cells, histologically expressed as greater cell heights, making the uterus resistant to E. coli.
