The fate of uterine spermatozoa in the mouse post coitum.

Abstract

Observations have been made on the fate of sperm remaining in the uterus of the mouse following coitus. The uterine contents were found to undergo two fates both of which resulted in the emptying of the organ within 36 hr. The first was degradation of the sperm by phagocytes and its subsequent absorption by the uterus, the second was the evacuation of the contents per vaginam at about the 16th hour post coitum. The process of degradation by phagocytes was arbitrarily divided into three stages, a first stage lasting until the 8th hour post coitum with no evidence of phagocytic activity, a second stage lasting until the 18th hour post coitum with very active phagocytosis both by polymorphonuclear neutrophil leucocytes and monocytes, and a terminal or absorptive phase lasting until the 36th hour post coitum when an active phagocytosis of the degraded phagocytes and other granular debris occurs through the uterine epithelial cells to the subepithelial lymphatic vessels. The similarity of the first phase to the concept of capacitation of sperm in connection with fertilization is discussed from the viewpoint of a proposed obligatory prephagocytic conditioning of the sperm surface, possibly of antibody nature. The involvement of polymorphonuclear neutrophil lysosomes in the degradation process of sperm is demonstrated, thereby supporting suggestions of a similar role for these particles as in microbial degradation. Examination of parametrial and abdominal lymph nodes shows a change in histology when the first is compared with the third stage. The follicle structure is less obvious and there is an increase in reticulo-endothelial cells and lymphoblasts, especially in the hilar region. The nodes contain debris reminiscent of the debris found in the uterine lumen, in the uterine epithelium, and subepithelial lymphatics. The presence of foreign protein, including foreign nucleoprotein, within the cytoplasm of uterine epithelial cells and lymph nodes which drain them is discussed from the perspectives of their genetic and immunological (e.g. homograft reaction) consequences.