The Influx of Leukocytes and Presence of Bactericidal Substances in Inoculated Uteri of Estrous and Pseudopregnant Rabbits

Abstract

Uterine horns of estrous and pseudopregnant rabbits were ligated and inoculated with Esch. coli. An association was found in the estrous rabbits. between leukocytic migration into the uterine lumen and bactericidal activity of the uterus during the early stages of the induced infection. Leukocytic response was slower in pseudopregnant rabbits and was not associated with apparent bactericidal activity. Microscopic examination of cellular debris from the inoculated uteri of the estrous rabbits failed to disclose significant numbers of phagocytized bacteria; therefore, leukocyte-free exudate from previously inoculated uteri of estrous rabbits was injected into inoculated uterine horns of pseudopregnant rabbits to test for a bactericidal effect of the exudate. Fewer bacteria were recovered from the exudate-infused horns than from control horns. However, the uterine exudate from the estrous rabbits may have stimulated the uterine defense mechanism of the pseudopregnant rabbits, as suggested by increased leukocytic influx into the infused horns. The exudate was then found to possess direct bactericidal activity in vitro. Washings from uninoculated uterine horns of estrous rabbits were not bactericidal in vitro. Leukocyte-free exudates from previously inoculated uteri of estrous and pseudopregnant rabbits were compared in vitro in regard to bactericidal properties; the exudate from estrous rabbits was more bactericidal. These results suggest that a difference in the amount of a bactericidal substance in uterine exudates may be at least partially responsible for the differential bactericidal activity of estrous and pseudopregnant rabbit uteri. Copyright © . .