title: Prematurational culture with 3-isobutyl-1-methylxanthine synchronizes meiotic progression of the germinal vesicle stage and improves nuclear maturation and embryonic development in in vitro-grown bovine oocytes.
abstract: The objective of this study was to clarify the effects of prematurational culture (pre-IVM) supplemented with 3-isobutyl-1-methylxanthine (IBMX) on nuclear and cytoplasmic maturation of in vitro-grown bovine oocytes. In experiment 1, oocytes (95 μm in diameter) derived from early antral follicles (0.5-1 mm in diameter) were cultured for 12 days for in vitro growth (IVG). IVG oocytes with a normal appearance were subjected to examinations of diameter and chromatin structure in the germinal vesicle (GV) before IVM. In addition, percentages of metaphase II (M II) were examined after IVM. Regardless of pre-IVM, the mean diameters of IVG oocytes were about 115 μm. The proportions of GV3 (50.0%) and M II stages (80.1%) of IVG oocytes with pre-IVM were higher than those without pre-IVM (28.0 and 49.4%, respectively). In experiment 2, the fertilizability and developmental competence of IVG oocytes were examined. Regardless of pre-IVM, the normal fertilization rates of IVG oocytes were similar (around 70%) but were lower than that of in vivo-grown oocytes (88.0%). Cleavage and blastocyst rates of IVG oocytes with pre-IVM (63.0 and 26.1%, respectively) were higher than those without pre-IVM (45.8 and 12.7%, respectively). The blastocyst rate based on cleaved IVG oocytes with pre-IVM (41.7%) was similar to that of in vivo-grown oocytes (48.7%), although the cleavage rate of IVG oocytes with pre-IVM was lower than that of in vivo-grown oocytes. In conclusion, pre-IVM with IBMX improved the maturational and developmental competences of IVG oocytes, probably due to promotion of their chromatin transition and synchronization of meiotic progression.
authors.affiliation: Laboratory of Theriogenology, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan.
authors.forename: Weiping
authors.initials: W
authors.lastname: Huang
authors.forename: Masashi
authors.initials: M
authors.lastname: Nagano
authors.forename: Sung-Sik
authors.initials: SS
authors.lastname: Kang
authors.forename: Yojiro
authors.initials: Y
authors.lastname: Yanagawa
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Takahashi
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology*; D000818:Animals; D002417:Cattle; D046149:Embryo Culture Techniques / Q000662:veterinary*; D047108:Embryonic Development / Q000187:drug effects*; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary*; D008540:Meiosis / Q000187:drug effects*; D009865:Oocytes / Q000166:cytology / Q000187:drug effects*
chemical_list: D015056:1-Methyl-3-isobutylxanthine