Fertilization of bovine oocytes grown in vitro.
Early antral follicles 0.5-0.7 mm in diameter were dissected from bovine ovaries, and oocyte-cumulus complexes with pieces of parietal granulosa (OCCGs) were then collected from the follicles. The OCCGs containing oocytes of 90-99 microm diameter (94.7+/-2.8 microm, n = 196) were selected and embedded in collagen gels and cultured for 14 days in TCM199 containing 10% fetal calf serum and 4 mM hypoxanthine. From cultured OCCGs, 144 surviving oocytes were recovered, of which 53 were granulosa cell-enclosed oocytes and 91 were denuded oocytes. The mean diameter of the surviving oocytes was 114.2+/-8.4 microm, significantly larger than that measured before culture (P < 0.05). The granulosa cell-enclosed oocytes and denuded oocytes were further cultured for maturation for 24 h. After culture, 72% (38/53) of the granulosa cell-enclosed oocytes and 59% (54/91) of the denuded oocytes showed normal morphology. These oocytes were then inseminated with bovine spermatozoa. After 29 h of insemination, all of the denuded oocytes had degenerated, while 32% (12/38) of the granulosa cell-enclosed oocytes showed normal morphology. Of the 12 oocytes, 5 were penetrated by spermatozoa, and 2 formed both male and female pronuclei. These results demonstrate for the first time that bovine oocytes grown in vitro acquire meiotic competence and can be penetrated by spermatozoa.
Osaki
S
S
The Graduate School of Science and Technology, Kobe University, Japan.
Matsumura
K
K
Yamamoto
K
K
Miyano
T
T
Miyake
M
M
Kato
S
S
D000818:Animals; D002417:Cattle / Q000502:physiology*; D002478:Cells, Cultured; D017364:Collagenases / Q000378:metabolism; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary*; D006107:Granulosa Cells / Q000502:physiology; D008297:Male; D009865:Oocytes / Q000502:physiology*; D013084:Sperm-Ovum Interactions
D017364:Collagenases