Effects of estrous cycle, steroids and localization of oviductal cells on in vitro secretion of sperm motility factor(s)

Abstract

Experiments were performed to study the effects of day of cycle, steroids and localization of oviductal cells on the maintenance of sperm motility in vitro. Oviductal cells from cows at different stages of the estrous cycle (Days 0 to 3, 10 to 12, 18 to 20) were separated (isthmus and ampulla) and cultured for 6 d in 24 well plates with TCM-199 and 10% FCS. Medium was then replaced with TCM-199 and 6 mg/ml BSA with or without 1 μg/ml progesterone (P) or estradiol-17β (E). After 48 h, conditioned media were tested for their ability to maintain bovine sperm motility for 6 h at 37 °C using a Hamilton Thorn motility analyzer. Without steroids, sperm motility was similar with the isthmus- and ampulla-conditioned media, regardless of the stage of the cycle. With E, isthmus cell-conditioned medium from early in the cycle resulted in a significant increase in sperm motility compared with that of the controls (55% ± 10 vs 37% ± 7; P < 0.01). With P, however, the medium conditioned with ampulla cells induced a net increase in sperm motility compared to nonconditioned medium (P < 0.05). Velocity of spermatozoa was also higher in conditioned media (± steroids; 123μm/sec ± 7) than that of controls (57 μm/sec ± 0.5; P < 0.0001). In summary, oviductal cells stimulate survival and motility of bovine sperm in vitro in a hormone-dependent manner.