title: Effect of follicle cells on in vitro fertilization of pig follicular oocytes.
abstract: We investigated the effect of cumulus and granulosa cells (follicle cells) on in vitro fertilization of pig follicular oocytes matured in vitro. Oocytes surrounded by cumulus and connected with a piece of parietal granulosa cells (complexes) were matured in vitro for 46hours and were then divided into 4 groups: Group I oocytes were surrounded by expanded cumulus and granulosa cells; Group II oocytes were surrounded by expanded cumulus cells; Group III were denuded oocytes; and Group IV were denuded oocytes with cumulus cells from other complexes. After incubation for 4 hours and 40 minutes with frozen, thawed and preincubated pig epididymal spermatozoa, the oocytes were cultured for 5 hours and 20 minutes. When oocytes were inseminated in the presence of cumulus cells, the penetration rates were higher (92.5% for Group II and 89.5% for Group IV) than when cumulus cells were not used for insemination (Group III, 66.8%) or when oocytes with follicle cells were inseminated (Group I, 72.3%). Denudation of follicle cells before insemination (Group III) decreased the percentage of male pronuclear formation (50.8%) compared with that of oocytes surrounded by follicle cells (66.7% for Group II and 80.2% for Group I). These results support the ability of a moderate number of follicle cells to facilitate sperm penetration of pig follicular oocytes and male pronuclear formation.
authors.affiliation: Department of Genetic Resources II National Institute of Agrobiological Resources Kannondai 2-1-2, Tsukuba, Ibaraki 305, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kikuchi
authors.forename: T
authors.initials: T
authors.lastname: Nagai
authors.forename: J
authors.initials: J
authors.lastname: Motlik
authors.forename: Y
authors.initials: Y
authors.lastname: Shioya
authors.forename: Y
authors.initials: Y
authors.lastname: Izaike