title: Changes in mitochondrial function in porcine vitrified MII-stage oocytes and their impacts on apoptosis and developmental ability.
abstract: The purpose of this study was to investigate the changes in mitochondria in porcine MII-stage oocytes after open pulled straw (OPS) vitrification and to determine their roles in apoptosis and in vitro developmental ability. The mitochondrial membrane potential (ΔΨm), reactive oxygen species (ROS) level, adenosine-5'-triphosphate (ATP) concentration, mitochondrial distribution, mitochondrial ultrastructure, early-stage apoptosis with Annexin V-FITC staining, survival rate, parthenogenetic developmental ability and related gene expression were measured in the present experiments. The results showed that: (1) the mitochondrial ΔΨm of vitrified-thawed oocytes (1.05) was lower than that of fresh oocytes 1.24 (P<0.05). (2) ROS level in the OPS vitrification group was much higher than that of the fresh group, while the ATP concentration was much lower than that of fresh group (P<0.05). (3) Early-stage apoptosis rate from the OPS vitrification group (57.6%) was much higher than that of fresh group (8.53%) (P<0.05), and the survival rate and parthenogenetic cleavage rate of OPS vitrified oocytes were much lower than those from fresh ones (P<0.05). (4) Vitrification not only disrupted the mitochondrial distribution of porcine MII-stage oocytes, but also damaged the mitochondrial ultrastructure. (5) After vitrification, the gene expression level of Dnm1 was up-regulated, and other four genes (SOD1, Mfn2, BAX and Bcl2) were down-regulated. The present study suggested that not only the morphology and function of mitochondria were damaged greatly during the vitrification process, but also early-stage apoptosis was observed after vitrification. Intrinsic mitochondrial pathway could be in involved in the occurrence of apoptosis in vitrified-thawed porcine oocytes.
authors.affiliation: College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu 210095, China; Institute of Animal Science and Veterinary Medicine, Shanghai Academy of Agricultural Sciences, Shanghai 201106, China; Division of Animal Genetic Engineering, Shanghai Municipal Key Laboratory of Agri-Genetics and Breeding, Shanghai 201106, China.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Dai
authors.affiliation: Institute of Animal Science and Veterinary Medicine, Shanghai Academy of Agricultural Sciences, Shanghai 201106, China; Division of Animal Genetic Engineering, Shanghai Municipal Key Laboratory of Agri-Genetics and Breeding, Shanghai 201106, China.
authors.forename: Caifeng
authors.initials: C
authors.lastname: Wu
authors.affiliation: College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu 210095, China.
authors.forename: Caroline W
authors.initials: CW
authors.lastname: Muneri
authors.affiliation: Institute of Animal Science and Veterinary Medicine, Shanghai Academy of Agricultural Sciences, Shanghai 201106, China; Division of Animal Genetic Engineering, Shanghai Municipal Key Laboratory of Agri-Genetics and Breeding, Shanghai 201106, China.
authors.forename: Yingfang
authors.initials: Y
authors.lastname: Niu
authors.affiliation: Institute of Animal Science and Veterinary Medicine, Shanghai Academy of Agricultural Sciences, Shanghai 201106, China; Division of Animal Genetic Engineering, Shanghai Municipal Key Laboratory of Agri-Genetics and Breeding, Shanghai 201106, China.
authors.forename: Shushan
authors.initials: S
authors.lastname: Zhang
authors.affiliation: College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu 210095, China. Electronic address: rrui@njau.edu.cn.
authors.forename: Rong
authors.initials: R
authors.lastname: Rui
authors.affiliation: Institute of Animal Science and Veterinary Medicine, Shanghai Academy of Agricultural Sciences, Shanghai 201106, China; Division of Animal Genetic Engineering, Shanghai Municipal Key Laboratory of Agri-Genetics and Breeding, Shanghai 201106, China. Electronic address: zhangdefuzdf@163.com.
authors.forename: Defu
authors.initials: D
authors.lastname: Zhang
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D015925:Cryopreservation / Q000379:methods*; D005260:Female; D053078:Membrane Potential, Mitochondrial / Q000502:physiology; D008928:Mitochondria / Q000473:pathology* / Q000502:physiology; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D010312:Parthenogenesis; D017382:Reactive Oxygen Species / Q000378:metabolism; D013552:Swine / Q000502:physiology*; D058989:Vitrification
chemical_list: D017382:Reactive Oxygen Species; D000255:Adenosine Triphosphate
keywords: Apoptosis; MII-stage oocyte; Mitochondria; OPS vitrification; Porcine