title: Sensitivity of the meiotic stage to hyperthermia during in vitro maturation of porcine oocytes.
abstract: The present study was conducted to clarify whether the meiotic stage of porcine oocytes has the highest sensitivity to hyperthermia during in vitro maturation by evaluating meiotic competence and DNA damage. Oocytes were exposed to 41 °C for 12 h at various intervals during 48 h of maturation culture. When the oocytes were exposed to 41 °C from 12 to 24 h of the maturation culture, the proportion of oocytes reaching metaphase II (MII) decreased as compared to the control oocytes cultured at 38.5 °C (P < 0.05). Moreover, the proportions of DNA fragmentation in all oocytes exposed to 41 °C in each culture period after 12 h from the start of maturation culture were significantly higher (P < 0.05) than for the control oocytes. When the meiotic stage of oocytes cultured at 38.5 °C between 12 and 24 h was examined, the majority of oocytes remained at the germinal vesicle (GV) stage at 12 h and approximately half of the oocytes reached metaphase I (MI) at 24 h. These results indicate that the meiotic stage of porcine oocytes having the highest sensitivity to hyperthermia during in vitro maturation is a transition period from the GV stage to the MI stage.
authors.affiliation: Laboratory of Animal Reproduction, Faculty of Bioscience and Bioindustry (Ishii campus), Tokushima University , Ishii, Myozai-gun, Tokushima 779-3233 , Japan.
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Nishio
authors.affiliation: Joint Faculty of Veterinary Science, Yamaguchi University , Yamaguchi , Japan.
authors.forename: Mado
authors.initials: M
authors.lastname: Yamazaki
authors.affiliation: Joint Faculty of Veterinary Science, Yamaguchi University , Yamaguchi , Japan.
authors.forename: Masayasu
authors.initials: M
authors.lastname: Taniguchi
authors.affiliation: Drug Safety Research Laboratory, Taiho Pharmaceutical Co. Ltd. , Tokushima , Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Besshi
authors.affiliation: Drug Safety Research Laboratory, Taiho Pharmaceutical Co. Ltd. , Tokushima , Japan.
authors.forename: Fumio
authors.initials: F
authors.lastname: Morita
authors.affiliation: Laboratory of Animal Reproduction, Faculty of Bioscience and Bioindustry (Ishii campus), Tokushima University , Ishii, Myozai-gun, Tokushima 779-3233 , Japan.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Kunihara
authors.affiliation: Laboratory of Animal Reproduction, Faculty of Bioscience and Bioindustry (Ishii campus), Tokushima University , Ishii, Myozai-gun, Tokushima 779-3233 , Japan.
authors.forename: Fuminori
authors.initials: F
authors.lastname: Tanihara
authors.affiliation: Fujii Memorial Institute of Medical Sciences, Tokushima University , Tokushima , Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Takemoto
authors.affiliation: Laboratory of Animal Reproduction, Faculty of Bioscience and Bioindustry (Ishii campus), Tokushima University , Ishii, Myozai-gun, Tokushima 779-3233 , Japan.
authors.forename: Takeshige
authors.initials: T
authors.lastname: Otoi
mesh_terms: D000818:Animals; D004249:DNA Damage; D006358:Hot Temperature; D059471:In Vitro Oocyte Maturation Techniques / Q000662:veterinary*; D008540:Meiosis / Q000502:physiology*; D009865:Oocytes / Q000502:physiology*; D013552:Swine / Q000502:physiology*
keywords: Heat stress; maturation; meiotic stage; quality; sensitivity