Inaugural ASAS–CAAV Asia Pacif ic Rim Conference Abstracts

T242 Ultrastructure of oocyte and early embryo on yak. P.Yan*, X. Guo, Y. Zeng, C. Liang, J. Pei, Lanzhou Institute of Animal Science &Veterinary Pharmaceutics, Chinese Academy of Agricultural Sciences, LanzhouCity, P. R. China.Ultrastructural study of the Chinese Yak oocytes was performed before andafter culturing in vitro maturation, and early embryo of different stages werealso examined to elucidate the structural characteristics of the ultrastructureand changes in development. The aim was to improve the theoretical basisand technology system for in vitro fertilization of yak. Before culturing ofthe oocytes, granulosa cells tightly wrapped oocytes, the slender microvilliof oocytes surface plunged into the zona pellucida, anda large number of cellorganelles distribution could be seen in the cortical areas and cell center. Afterculture, the mature granulosa cells bonded loosely with oocytes, the microvilli ofoocyte surface lodged on the egg surface, and an even cytoplasmic distributionof organelles in the cell was found. Pyknosis could be seen in granulosa cellsaround mature oocytes, gap junction between granulosa cells was growing andbecame more clearly visible, with increased vacuolization at the same time. Invitro fertilization, the early embryonic inner cell masses set up the connectionby cytoplasmic connection, gap junction, and liposome connection. All kindsof organelles and lipid droplets located in the cytoplasm and the latter showedthe following features: evenly distributed homogeneously, mostly around thelipid droplets with mitochondria, Golgi complexes, and endoplasmic reticulum.There were a small number of mitochondria in hooded mitochondria and manymitochondria existed in the cytoplasm at 16-cell and 32-cell stage embryos.Meanwhile lipid droplets and rod-like mitochondrias appeared in this periodindicating that mitochondrias showed a circular or cap-like matrix shallow ridgeedge to the rod-like maturation changes with the development of early embryos;increased number of mitochondrias and cross-ridge in morula period showedthe increasing fetal respiratory function at that time. A layer of trophoblast cellsin flat or cube differentiated from both sides of the blastocyst inner cell mass,and connected with inner cell mass by connecting trophoblast complex, cellmass of blastocysts microvillied into the cavity, the role of microvilli at thisphase were involved in the cell function.T244 Live offspring produced from ovarian heterosexualgrafts in castrated male mice with estradiol follow-up. F. Li*, Y. Tao, Y.Zhang, Y. Li, F. Fang, Y. Liu, H. Cao, X. Zhang, and S. Zhou, College of AnimalScience and Technology, Anhui Agricultural University, Hefei, China.Ovary grafting is not only a method to investigate the follicle development,but also a model to explore the possibility of re-obtaining reproductivityin male-to-female sexual reverse. The present study was undertaken tostudy the ovary survival and follicle development after fresh ovaries wereheterosexually transplanted into the castrated male mice. Ten-day-old mouseovaries were heterosexually transplanted into the back muscle of 8-10 weeksold outbred castrated male mice with the treatment of gonadotrophins andimmunosuppressants. Twenty-two days later, the ovarian structure and folliculardensities were examined by hematoxylin and eosin staining. The oocytes wereharvested and then for in vitro maturation (IVM) and in vitro fertilization (IVF).The results showed that many follicles at different developmental stage wereobserved in the grafts, comparing with 32-day-old fresh ovary, the differenceof the primordial, preantral and antral follicular densities were not obvious (P> 0.05). Blastocysts were derived from collected oocytes after IVM and IVFwith high cleavage rate (72.4%) and blastocysts rate (7.9%), and three live pupswere produced by embryo transfer. The hormone assay showed that the plasmaconcentrations of both estrogen (E2) and progesterone (P4) increased afterovarian transplantation (P < 0.01). These results demonstrate that the folliclesundergo further development with endocrine function after the mouse ovariesare allografted into the back muscle of the castrated male mice.Key Words: ovary allograft, mouse, follicleKey Words: oocyte, ultrastructure, yakT243 Effects of oxygen tension, medium and WOW on invitro development of mouse embryo. C. Zubing*, W. Wei, L. Wenhao, Z.Shixian, L. Yunsheng, T. Yong, Z. Xiaorong, and Z. Yunhai, College of AnimalScience and Technology, Anhui Agricultural University, Hefei, P.R. China.The objectives of the present research were to investigate whether embryoculture media have preferences to oxygen tension, and to explore feasibility ofusing physical lung air to support the in vitro development of mouse embryos,and to evaluate effect of Well of the Well(WOW) culture on in vitro preimplantationaldevelopment of mouse embryos. The results are: First, cleavagerate and blastocyst rate were not significantly different between medium CZBand mKSOM regardless of on the use of three gas phases: 4% CO 2+ 16%O 2+ 78% N 2+ 2% H 2O (lung air) , 5% CO 2+ 5% O 2+ 90%N 2(5% O 2, lowoxygen) and 5% CO 2+ 95% air (20% O 2, high oxygen; P > 0.05), but meantotal cell numbers per blastocyst cultured in CZB medium were higher thanthat in mKSOM when the lung air was used (P < 0.05). Second, based onmKSOM medium, the blastocyst rate (22.6%) in 5% O 2gas phase was notablyhigher than that in other two gas phase (P < 0.05). Third, as for CZB medium,blastocyst rate was not different significantly among three gas environments(P > 0.05). Fourth, both the blastocyst rate (74.6 ± 5.1%) and the mean totalcell numbers per blastocyst (76 ± 2) cultured in WOW system were obviouslyhigher than that in the group culture system (38.2 ± 6.6% and 58 ± 4). Takentogether, these results indicate that the mKSOM medium and the CZB mediumhave their corresponding preferences to oxygen tension during in vitro cultureof mouse embryos, and the lung air was reaffirmed to be able to effectivelysupport in vitro pre-implantation development of mouse embryos, and WOWculture system can apparently enhance the in vitro developmental competenceand blastocyst quality of mouse embryos.Key Words: mouse embryo, preferences, WOW culture69