Quantitation of sperm disposal and phagocytic cells in the tract of short- and long-term vasectomized mice

By calculating the number of spermatozoa produced by the mouse testis after vasectomy, and actually counting the number of spermatozoa present in the epididymides and vasa deferentia, the number of spermatozoa resorbed at different times was quantified. The contributions of sperm phagocytosis and intraluminal dissolution of spermatozoa (separate sperm heads and tails) in sperm disposal were examined. Sperm resorption was clearly demonstrated, with about 100 X 10(6) spermatozoa and 426 X 10(6) spermatozoa having been resorbed by 6 weeks and 6 months after vasectomy, respectively. A characteristic of the vasectomized tract was the high proportion of degenerating spermatozoa, and small lymphocytes, but very few intraluminal phagocytes were observed. The results suggest that spermatozoa are resorbed after vasectomy and that intraluminal sperm dissolution, rather than phagocytosis, is a prominent mechanism of sperm disposal in the tract of the vasectomized mouse.