title: Preimplantation development of cloned canine embryos recovered by hysterectomy or surgical uterine flushing and subsequent pregnancy outcomes.
abstract: Dog cloning offers a substantial potential because of the advancements in assisted reproductive technology and development of the human disease model in line with the transgenic technique. However, little is known about the development of the canine cloned embryo during the preimplantation period. The aim of this study was to investigate the most efficient method and time for collecting cloned canine preimplantation embryos and to ascertain the developmental timeline of cloned canine embryos. Two hundred cloned embryos were created and transferred into 11 surrogates. The preimplantation stage cloned embryos were then collected on Days 7, 8, and 9 using an ovariohysterectomy or the Foley balloon catheter method. The recovery rate of reconstructed embryos was 63.6% and 60.6% for the ovariohysterectomy and Foley balloon catheter methods, respectively. Although significant differences were observed in the early developmental stages (one-cell and 16-cell stages), no significant difference was observed in the blastocyst stage. Significantly higher blastocyst rate was observed when the embryos were collected on Day 8 (11.4%) than on Day 7 (0.0%; P < 0.05). At the proximal uterine horn on Day 7, no embryos at any stage were found, whereas on Days 8 and 9, blastocysts were found. We have observed a 63% initial pregnancy rate at 25 to 30 days after embryo transfer and a 50% full-term pregnancy rate, whereas 6.3% of the puppies were born, and 5.5% were born live among the total transferred embryos. Our results suggest that cloned embryos can develop to blastocysts by Day 8, and full-term pregnancy can be achieved after embryo transfer in canine.
authors: Sooam Biotech Research Foundation, Seoul, Republic of Korea.
authors: Yeon Woo
authors: YW
authors: Jeong
authors: Sooam Biotech Research Foundation, Seoul, Republic of Korea.
authors: Joung Joo
authors: JJ
authors: Kim
authors: Sooam Biotech Research Foundation, Seoul, Republic of Korea.
authors: Hyun Duk
authors: HD
authors: Kim
authors: Sooam Biotech Research Foundation, Seoul, Republic of Korea.
authors: Kyu Chan
authors: KC
authors: Hwang
authors: Sooam Biotech Research Foundation, Seoul, Republic of Korea; Laboratory of Veterinary Embryology and Biotechnology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Republic of Korea.
authors: Sang Hwan
authors: SH
authors: Hyun
authors: Department of Animal Sciences, Chungbuk National University, Cheongju, Republic of Korea.
authors: Nam-Hyung
authors: NH
authors: Kim
authors: Laboratory of Veterinary Biochemistry and Molecular Biology, Chungbuk National University, Cheongju, Republic of Korea.
authors: Eui-Bae
authors: EB
authors: Jeung
authors: Sooam Biotech Research Foundation, Seoul, Republic of Korea. Electronic address: hwangws@sooam.org.
authors: Woo Suk
authors: WS
authors: Hwang
mesh_terms: D000818:Animals; D019976:Cloning, Organism; D004285:Dogs / Q000196:embryology*; D004624:Embryo Transfer / Q000379:methods / Q000662:veterinary; D005260:Female; D007044:Hysterectomy / Q000662:veterinary*; D011247:Pregnancy; D011256:Pregnancy Outcome; D011270:Pregnancy, Animal; D020858:Tissue and Organ Harvesting
keywords: Canine preimplantation embryos; Dog cloning; Embryo recovery