Maturation and fertilization of porcine oocytes from primordial follicles by a combination of xenografting and in vitro culture.
Our objective was to develop a method of endowing oocytes from porcine primordial follicles with full maturation and fertilizing ability as a model for ovarian xenografting of large mammals. Ovarian tissues from 20-day-old piglets, in which most of the follicles were primordial, were transplanted under the capsules of both kidneys of ovariectomized athymic mice. The host mice were treated with 5 IU of equine chorionic gonadotropin (eCG) for 10 days (eCG-10), 30 days (eCG-30), or 60 days (eCG-60) after detection of cornified epithelial cells in their vaginal smears. Cumulus-oocyte complexes, ovarian grafts, and blood samples were obtained 48 h after eCG treatment. Forty-five to 70 days after grafting, the host mice in all groups for the first time showed vaginal cornification, accompanied by the formation of a small number of antral follicles in the grafts. However, we recovered large numbers of full-sized oocytes only from mice in the eCG-60 group; the numbers of full-sized oocytes in the other groups were low. Peripheral levels of total inhibin were highest in the eCG-60 group; this supports our finding that the most enhanced growth of antral follicles occurred in this eCG-60 group. Of 573 oocytes obtained from the eCG-60 group, 98 (17%) were at the metaphase II stage after in vitro culture for maturation. Moreover, 55% of matured oocytes with the first polar body (n = 20) were fertilized in vitro. These results clearly demonstrate that fertilization of oocytes from porcine primordial follicles is achievable by a combination of xenografting and in vitro culture.
Kaneko
Hiroyuki
H
Genetic Diversity Department, National institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan. kaneko@nias.affrc.go.jp
Kikuchi
Kazuhiro
K
Noguchi
Junko
J
Hosoe
Misa
M
Akita
Tomiji
T
D000818:Animals; D002467:Cell Nucleus / Q000502:physiology; D017690:Cell Transplantation / Q000502:physiology; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D005260:Female; D005307:Fertilization in Vitro; D005455:Fluorescent Antibody Technique; D007265:Inhibins / Q000096:biosynthesis; D007668:Kidney / Q000166:cytology; D051379:Mice; D009865:Oocytes / Q000502:physiology*; D006080:Ovarian Follicle / Q000502:physiology*; D010053:Ovary / Q000166:cytology / Q000637:transplantation*; D013552:Swine; D014183:Transplantation, Heterologous
D006063:Chorionic Gonadotropin; D007265:Inhibins