Changes in epididymal spermatozoa and in the testes of rabbits after experimental cryptorchidism

Abstract Surgical cryptorchidism was induced in sexually mature rabbits by a scrotal incision approach or an abdominal approach, and the effects were observed for the next 14 days. Various combinations of ligatures on the corpus epididymidis and ductus deferens were employed to compare effects with and without restricted sperm movement. Neither cryptorchidism nor epididymal ligatures reduced libido. However, ejaculate volume significantly decreased after 14 days of cryptorchidism (P < 0.05), and this may have resulted from a reduction in contributions by the epididymis as indicated by oligospermia. Damage due to cryptorchidism was significantly more severe on sperm in the caput than in the cauda epididymidis. Four days of cryptorchidism caused an increase in percent of abnormal spermatozoa at all levels of the epididymis. It did not alter the percent of unstained sperm or fertility of sperm in the cauda epididymidis. Thus, uncapacitated sperm in the male at body temperature retain their fertilizing potential for considerably longer periods than capacitated sperm do in the female. Cryptorchidism for seven or more days resulted essentially in a complete loss of fertility of cauda sperm. Caput sperm usually were infertile initially, and after retention by ligation or after the elevation of temperature by cryptorchidism. Testicular alterations were detected after one or more days of cryptorchidism, characterized by cellular sloughing, giant cells, absence of tubules in stage 8 and testicular and tubular shrinkage. Ligatures on the corpus also caused fluid and sperm accumulation and interfered with spermatogenesis. This fluid accumulation was associated with a significant increase in caput epididymal weights (P < 0.05).