title: Beneficial effect of young oocytes for rabbit somatic cell nuclear transfer.
abstract: This study was designed to examine the effect of the age of rabbit oocytes on the developmental potential of cloned embryos. The metaphase II oocytes used for nuclear transfer (NT) were collected at 10, 12, 14, and 16 h post-hCG injection (hpi). The total number of oocytes collected per donor (21.4-23.7) at 12 to 16 hpi was similar, but significantly higher than that collected at 10 hpi (16.2). Additionally, a significant improvement in blastocyst development was achieved with embryos generated by electrically mediated cell fusion (56.0%), compared to those from nuclear injection (13.1 %) (Experiment 1). Markedly higher blastocyst development (45.8-54.5%) was also achieved with oocytes collected at 10-12 hpi than from those collected 14-16 hpi (8.3-14.3%) (Experiment 2). In Experiment 3, the blastocyst rates of NT embryos derived from oocytes harvested 12 hpi (39.2-42.8 %) were significantly higher than from those collected at 16 hpi (6.8-8.4 %) (p < 0.05), regardless of the donor cell age. Kinase activity assays showed variable changes of activity in rabbit oocytes over the period of 10-16 hpi; however, there was no correlation with preimplantational development (blastocyst rate vs. MPF, R = 0.326; blastocyst rate vs. MAPK, R = -0.131). Embryo transfer of NT embryos utilizing 12 hpi oocytes resulted in one full-term but stillborn, and one live cloned rabbit; thus, an efficiency of 1.7 % (n = 117) (Experiment 4). These results demonstrated that NT utilizing relatively young rabbit oocytes, harvested at 10-12 h after hCG injection, was beneficial for the development of NT embryos.
authors.affiliation: Evergen Biotechnologies, Inc, Vernon, Connecticut 06066, USA. fuliangd@evergen.com
authors.forename: Fuliang
authors.initials: F
authors.lastname: Du
authors.forename: Jie
authors.initials: J
authors.lastname: Xu
authors.forename: Jifeng
authors.initials: J
authors.lastname: Zhang
authors.forename: Shaorong
authors.initials: S
authors.lastname: Gao
authors.forename: Mark G
authors.initials: MG
authors.lastname: Carter
authors.forename: Chingli
authors.initials: C
authors.lastname: He
authors.forename: Li-Ying
authors.initials: LY
authors.lastname: Sung
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Chaubal
authors.forename: Rafael A
authors.initials: RA
authors.lastname: Fissore
authors.forename: X Cindy
authors.initials: XC
authors.lastname: Tian
authors.forename: Xiangzhong
authors.initials: X
authors.lastname: Yang
authors.forename: Y Eugene
authors.initials: YE
authors.lastname: Chen
mesh_terms: D000367:Age Factors; D000818:Animals; D016922:Cellular Senescence; D019976:Cloning, Organism / Q000379:methods*; D016200:Maturation-Promoting Factor / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D053652:Nuclear Transfer Techniques; D009865:Oocytes / Q000201:enzymology / Q000502:physiology*; D011817:Rabbits
chemical_list: D016200:Maturation-Promoting Factor; D020929:Mitogen-Activated Protein Kinase Kinases