title: Coculture with good-quality COCs enhances the maturation and development rates of poor-quality COCs.
abstract: In pigs, more than half of the recovered cumulus cell-oocyte complexes (COCs) have one or two layers of cumulus cells and are considered morphologically poor. If we could take full advantage of these poor-quality COCs, we could potentially improve the efficiency of in vitro embryo production. During IVM, although some maturation factors are transmitted bidirectionally between the oocyte and the cumulus cells of the same COC, transmission also occurs between different COCs. We hypothesized that morphologically poor COCs fail to undergo complete oocyte maturation because of their insufficient secretion of maturation factors. Here, we investigated whether coculture with morphologically good COCs (having three or more layers of cumulus cells) could improve the maturation and utilization rates of morphologically poor COCs. Our results revealed that the oocyte maturation rate, glutathione level, embryo development capacity, blastocyst quality, and cumulus cell gene expression levels of BCL-2 and proliferating cell nuclear antigen were similar in the coculture and good-quality groups and that these levels were all significantly higher than those in the poor-quality group. Our results strongly suggest that the coculture strategy greatly improved the utilization rate of morphologically poor COCs without reducing their capacity for maturation and subsequent development.
authors.affiliation: Department of Animal Science and Biotechnology, Research Center for Transgenic Cloned Pigs, Chungnam National University, Daejeon, Republic of Korea.
authors.forename: Tao
authors.initials: T
authors.lastname: Lin
authors.affiliation: Department of Animal Science and Biotechnology, Research Center for Transgenic Cloned Pigs, Chungnam National University, Daejeon, Republic of Korea.
authors.forename: Reza K
authors.initials: RK
authors.lastname: Oqani
authors.affiliation: Department of Animal Science and Biotechnology, Research Center for Transgenic Cloned Pigs, Chungnam National University, Daejeon, Republic of Korea.
authors.forename: Jae Eun
authors.initials: JE
authors.lastname: Lee
authors.affiliation: Department of Animal Science and Biotechnology, Research Center for Transgenic Cloned Pigs, Chungnam National University, Daejeon, Republic of Korea.
authors.forename: Hyun Young
authors.initials: HY
authors.lastname: Shin
authors.affiliation: Department of Animal Science and Biotechnology, Research Center for Transgenic Cloned Pigs, Chungnam National University, Daejeon, Republic of Korea. Electronic address: dijin@cnu.ac.kr.
authors.forename: Dong Il
authors.initials: DI
authors.lastname: Jin
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000502:physiology; D018920:Coculture Techniques / Q000662:veterinary*; D054885:Cumulus Cells / Q000502:physiology*; D047108:Embryonic Development / Q000502:physiology; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary; D015870:Gene Expression; D005978:Glutathione / Q000032:analysis; D059471:In Vitro Oocyte Maturation Techniques / Q000379:methods / Q000662:veterinary*; D009865:Oocytes / Q000254:growth & development / Q000502:physiology*; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D034421:Sus scrofa
chemical_list: D018809:Proliferating Cell Nuclear Antigen; D019253:Proto-Oncogene Proteins c-bcl-2; D005978:Glutathione
keywords: Coculture; Cytoplasmic maturation; Embryo development; IVM; Nuclear maturation