Effects of 17 beta-oestradiol or oestrous stage-specific cow serum on the ability of bovine oviductal epithelial cell monolayers to prolong the viability of bull spermatozoa

The effect of 17 beta-oestradiol and oestrous stage-specific cow serum on b ovine oviductal epithelial cell monolayers to extend the viability of co-cu ltured bull spermatozoa was examined. Monolayers of cells from ampullary an d isthmic segments were pre-treated with medium containing either oestrous cow serum, luteal-phase cow serum, 1 mu g/ml 17 beta-oeshadiol + foetal bov ine serum or foetal bovine serum alone (control) before the addition of mot ile frozen/thawed spermatozoa. Motility was visually assessed throughout a 48 h co-incubation period, while fertilising ability of spermatozoa was eva luated by adding in vitro matured bovine oocytes. Pre-treatment with 17 bet a-oestradiol or oestrous cow serum resulted in a higher percentage of motil e spermatozoa after 18 h in isthmic and after 36 h in ampullary cultures co mpared with the control, but pre-treatment did not,affect fertilisation rat es. Only at 42 h in ampullary cultures was motility higher in luteal serum pre-treated cultures compared to the control. Motility was also assessed in medium conditioned by pre-treated monolayers; Pre-treatment with 17 beta-o estradiol enhanced the ability of conditioned medium to prolong motility an d medium conditioned with oestrous cow serum was superior to medium conditi oned by luteal-phase serum at maintaining motility. In conclusion, the abil ity of oviductal epithelium to prolong the motility of spermatozoa is enhan ced by 17 beta-oestradiol. (C) 1999 Elsevier Science B.V. All rights reserv ed.