title: Meiotic inhibition of bovine oocytes in medium supplemented with a serum replacer and hormones: effects on meiosis progression and developmental capacity.
abstract: Aiming to improve the developmental competence of bovine oocytes during meiotic block, this study evaluated the effects of a serum replacer (Knockout SR®) and hormones (gonadotropins and estradiol) supplementation of prematuration medium (TCM119 with 0.5 mM IBMX [IBMX group] or 25 μM roscovitine [ROSC group]) on the kinetics of oocyte nuclear maturation and embryo development. Most IBMX and ROSC oocytes prematured for 8 h culture remained in the GV stage (70.3% and 73.1%, respectively; p > 0.05) similar to Control 8 h (63.5%) and to control immature oocytes (Control 0 h, 92.5%). After prematuration for 16 h, no oocytes remained in the GV stage at similar rates to those recently aspirated (p < 0.05); GV rates in ROSC (32.4%) were higher (p < 0.05) than in the Control 16 h group (8.6%), but similar (p > 0.05) to IBMX (9.7%). After in vitro maturation (IMV) for 24 h, metaphase II (MII) rates for oocytes prematured during 8 h were similar (p > 0.05) between control and treatments (65.0-71.7%). Similarly, MII rates oocytes prematured during 16 h were similar (p > 0.05) between all groups (45.9-60.4%). Cleavage rates (67.8-78.2%), embryonic development in day-7 (25.0-35.6%) and hatching rates in day-8 (2.5-11.3%) oocytes blocked during 8 h were similar for all groups (p > 0.05). Results indicate that addition of Knockout SR® and hormones to meiotic block culture with IBMX and roscovitine negatively affected meiotic arrest, but did not impair oocyte nuclear maturation and acquisition of developmental competence.
authors.affiliation: School of Agricultural and Veterinary Sciences, Department of Animal Reproduction, UNESP, 14884-900 Jaboticabal, SP, Brazil.
authors.forename: Letícia Siqueira
authors.initials: LS
authors.lastname: Sá Barretto
authors.forename: Viviane Sgobbi Dias Caiado
authors.initials: VS
authors.lastname: Castro
authors.forename: Joaquim Mansano
authors.initials: JM
authors.lastname: Garcia
authors.forename: Gisele Zoccal
authors.initials: GZ
authors.lastname: Mingoti
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D002467:Cell Nucleus; D003470:Culture Media / Q000737:chemistry; D047108:Embryonic Development / Q000187:drug effects; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D005307:Fertilization in Vitro; D006062:Gonadotropins / Q000494:pharmacology; D008540:Meiosis / Q000187:drug effects*; D009865:Oocytes / Q000166:cytology* / Q000187:drug effects*; D011687:Purines / Q000494:pharmacology; D000077546:Roscovitine
chemical_list: D003470:Culture Media; D006062:Gonadotropins; D011687:Purines; D000077546:Roscovitine; D004958:Estradiol; D015056:1-Methyl-3-isobutylxanthine