Exploring cumulus-oocyte-complex-oviductal cell interactions: gene profiling in the bovine oviduct

Prostaglandin E(2) (PGE(2)) is present in the bovine oviduct and may play an important role in muscle contraction or as survival factor providing the optimal environment for fertilization and the early embryo. The aim of the present study was to investigate the estrous cycle-dependent changes and local distributions of PGE(2) receptors (EP) and members of the trefoil factor (TFF)-family in the bovine oviduct using real-time RT-PCR. A co-cultivation system of cumulus-oocyte-complexes (COC) with primary oviductal cells was screened for the mRNA expression pattern of selected factors. An oviductal primary cell culture was used for investigating effects of estradiol on signal transduction pathways. Quantitative RT-PCR revealed significant higher expression of EP2 and EP4 in the pre-ovulatory phase compared with the luteal phase. TFF3 mRNAwas expressed during the estrous cycle with highest level in the post-ovulatory phase showing higher expression levels in the isthmus compared with the ampulla. A different mRNA expression pattern was observed for factors involved in extracellular matrix formation in co-cultured oviductal cells compared to untreated controls. In vitro, NF-kappaB was found activated after estradiol treatment. These results suggest that a fine-tuned PGE(2) signal transduction pathway may support fertilization, early embryonic development and gamete transport in the bovine oviduct.