Oviductal epithelial cells selected boar sperm according to their functional characteristics

The interaction of oviductal epithelial cells （OECs） with the spermatozoa has beneficial effects on the sperm functions. The aim of this study is to evaluate the in vitro fertilizing capacity of incubating spermatozoa previously selected by density gradient in OEC and determinate some sperm characteristics that could explain the results obtained. In this study, we assessed in vitro fertilization （IVF）, tyrosine phosphorylation, phosphatidylserine translocation, nuclear DNA fragmentation, and chromatin decondensation. Three experimental sperm groups, previously selected by Percoll gradient, were established according to the origin of the sperm used for IVF： （i） W30 group： spermatozoa were incubated with oocytes in the absence of OEC; （ii） NB group： after sperm incubation in OEC, the unbound spermatozoa were incubated with oocytes, in the absence of OEC; and （iii） B group： after sperm incubation with OEC, the bound spermatozoa were incubated with oocytes in the OEC plates. The results showed that sperm from the NB group led to a lower IVF yield, accompanied by low penetration rates （NB： 19.6%, B： 94.9%, and W30： 62.9%; P 〈 0.001） and problems of nuclear decondensation. Moreover, higher levels of tyrosine phosphorylation were observed in the NB group compared with the W30 and B groups （NB： 58.7%, B： 2.5%, and W30： 4.5%; P 〈 0.01）. A similar trend was observed in phosphatidylserine translocation （NB： 93.7%, B. 5.7%, and W30： 44.2%; P 〈 0.01）. These results demonstrate that the OEC exerts a rigorous degree of sperm selection, even within an already highly selected population of spermatozoa, and can capture the best functional spermatozoa for fertilization.

Mechanisms of Up-regulation of 17β-Estrodiol on β-Defensin-2 ( SBD-2) Expression in Epithelial Cells of Ovine Oviduct

[ Objective] To investigate the mechanisms involved in the Up-regulatory effects of 17β-estrodiol on β-defensin-2 （SBD-2） in epithelial cells of ovine oviduct. [ Methods] Epithelial cells of ovine oviduct were isolated and cultured; and then the cultured cells at secondary generation were divided into 17β-estradiol （E2, 10^-8 tool/L） group, estrogen nuclear receptor antagonist ICI182780 （10^-7 tool/L） group, PKA antagonist KT-5720 （1 μmol/L） group, PKC antagonist H- 7（50 μmol/L） group, nuclear factor kappa B antagonist PDTC（50μmol/L） group and the blank control group （ Control ）. Firstly, different antagonists were added into corresponding antagonist groups in order to interfere the epithelial ceils of ovine oviduct for 1 h. Then, 17β-estradiol （ 10^-8 mol/L） was added into each antagonist group and E2 group for cultivation for 6 h. Finally, real-time fluorescent quantitative RT-PCR was used to detect the changes of SBD-2 mRNA expression. [ Results] 10^-8 mol/L 17β-estrodiol had significantly Up-regulatory effects on the expression of SBD-2 mRNA （P 〈 0. 05 ）. Estrogen nuclear receptor antagonist ICI182780, NF-κB antagonist PDTC and PKC antagonist H-7 could all block the Up-regnlatory effects on SBD-2. But PKA antagonist KT-5720 showed no significant effects on the Up-regulation of SBD-2 mRNA expression induced by 17β-estrodiol. [ Conclusions] SBD-2 mRNA expression induced by 17β-estrodiol in epithelial cells of ovine oviduct was mediated by estrogen nuclear receptor ICI182780, NF-κB and PKC pathways. However, PKA pathway might not participate in the Up-regulation of SBD-2 mRNA expression.