Time-related changes in functional activity of mouse spermatozoa during in vitro or in vivo incubation

The kinetics of functional modifications during in vivo or in vitro incubation was studied in spermatozoa from Albino Swiss mice, obtained from cauda epididymis (E) or from uterus (U) or oviduct (O) post copulation (p.c.). Results clearly suggest that functional activity as reflected by measurements of motility, hypoosmotic swelling test and acrosome reaction differs according to the segments of the reproductive tract from which they were collected. The comparison of results obtained after equivalent periods of in vitro or in vivo incubation, shows that the time course of changes in sperm motility and percentage of swollen sperm is similar in both conditions. Since the percentage of acrosome-reacted gametes was higher in O, at all times scored, oviductal environment appeared to be capable of inducing this phenomenon. Our experimental conditions seemed to be adequate for completion of spermatozoa maturation and successful interaction between male and female gametes as reflected by the results of fertilization rate and embryo cleavage.