title: Cyclooxygenase-2 is expressed by cumulus cells during oocyte maturation in cattle.
abstract: Prostaglandins could be involved in various aspects of final differentiation of ovarian follicles. Prostaglandins are generated by the cyclooxygenase (cox) pathway. Until now, the expression pattern of isoforms cox-1 and cox-2 of cyclooxygenase in bovine cumulus-oocyte complexes (COCs) was unknown. Using immunodetection procedure, we demonstrated in the present study that cox-2 was expressed by cumulus cells during in vivo and in vitro maturation. Time course induction of cox-2 expression was investigated during in vitro maturation using Western blot analysis. Specific signal of cox-2 was markedly evidenced from 6 hr of culture and increased to reach a maximal level at 24 hr of culture. In vitro, cox-2 expression in COCs was associated with increased concentrations of PGE(2) and PGF(2alpha) in the maturation medium. In addition, the effects of culture conditions on cox-2 expression was considered using RT-PCR and Western-blot analysis. We demonstrated that the addition of 10 ng/ml of EGF to TCM199 clearly increased the expression level of cox-2 mRNA and protein. Higher levels of in vitro cox-2 expression was associated with greater rates of cumulus expansion and oocytes at metaphase II at 24 hr of culture. In conclusion, our present results suggest that cox-2 expression in cumulus cells may be involved in differentiation of COCs that occurs during oocyte maturation.
authors.affiliation: Ecole Nationale Vétérinaire d'Alfort, Unité de Biologie de la Reproduction, Maisons-Alfort, France. nuttinck@vet-alfort.fr
authors.forename: F
authors.initials: F
authors.lastname: Nuttinck
authors.forename: P
authors.initials: P
authors.lastname: Reinaud
authors.forename: H
authors.initials: H
authors.lastname: Tricoire
authors.forename: C
authors.initials: C
authors.lastname: Vigneron
authors.forename: N
authors.initials: N
authors.lastname: Peynot
authors.forename: J P
authors.initials: JP
authors.lastname: Mialot
authors.forename: P
authors.initials: P
authors.lastname: Mermillod
authors.forename: G
authors.initials: G
authors.lastname: Charpigny
mesh_terms: D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D015153:Blotting, Western; D002417:Cattle; D018929:Cell Culture Techniques / Q000379:methods; D002851:Chromatography, High Pressure Liquid; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D015237:Dinoprost / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism; D005260:Female; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D009865:Oocytes / Q000254:growth & development* / Q000378:metabolism; D009866:Oogenesis / Q000235:genetics / Q000502:physiology; D006080:Ovarian Follicle / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011863:Radioimmunoassay; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
chemical_list: D007527:Isoenzymes; D012333:RNA, Messenger; D016718:Arachidonic Acid; D015237:Dinoprost; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone