title: Granulosa cells inhibit the resumption of meiosis in bovine oocytes in vitro.
abstract: The oocytes of cattle are not as sensitive as those of laboratory animals to purines, cAMP, or follicular extracts. To study the resumption of meiosis, a method is needed that is capable of inhibiting meiosis completely for a minimum of 24 h. This study was designed to evaluate interrelationships in granulosa-oocyte-cumulus complexes using fresh granulosa cells aspirated from small follicles (1-5 mm) in which the cumulus is normally firmly attached. Selected oocyte-cumulus complexes obtained from a slaughterhouse (n = 2,236) were co-incubated with one of the following: various concentrations of fresh granulosa cells in tissue cultures medium (TCM) 199 or bovine follicular fluid (BFF) either without or after one washing and/or freezing; resuspended granulosa cells previously cultured for 7 days; blood cells; or medium alone. Additionally, oocyte-cumulus complexes were embedded in agar cylinders before incubation with or without cells. The rate of maintenance of intact germinal vesicles (GV) in oocytes after 24 h ranged from 40-77% when 5-100 x 10(6) unwashed cells/ml BFF were used, compared to only 16% in oocytes cultured in BFF alone. The pattern was the same when washed cells were used (30-77%, using 5-100 x 10(6) cells/ml BFF), but they were not as effective as unwashed cells. With TCM-199 and the same five concentrations of cells (5, 10, 25, 50, and 100 x 10(6)/ml), a similar inhibition was obtained with greater than or equal to 25 but not with 5 (3%) or 10 (5%) x 10(6)/ml.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Département de Zootechnie, Université Laval, Ste-Foy, Québec, Canada.
authors.forename: M A
authors.initials: MA
authors.lastname: Sirard
authors.forename: S
authors.initials: S
authors.lastname: Bilodeau
mesh_terms: D000362:Agar; D000818:Animals; D001773:Blood Cells / Q000502:physiology; D002417:Cattle; D002452:Cell Count; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D015571:Follicular Fluid / Q000502:physiology; D006107:Granulosa Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D008540:Meiosis / Q000187:drug effects / Q000502:physiology; D009865:Oocytes / Q000166:cytology / Q000187:drug effects / Q000254:growth & development*; D011687:Purines / Q000494:pharmacology
chemical_list: D011687:Purines; D000362:Agar; D000242:Cyclic AMP