
TY  - JOUR
A1  - Osaki, Shigeru 
A1  - Matsumura, Kenji 
A1  - Yamamoto, Ken 
A1  - Miyano, Takashi 
A1  - Miyake, Masashi 
A1  - Kato, Seishiro 
T1  - Fertilization of bovine oocytes grown <emph type="2">in vitro</emph>
JF  - Reproduction, Fertility and Development
JO  - Reprod. Fertil. Dev.
Y1  - 1998
VL  - 9
IS  - 8
SP  - 781
EP  - 788
KW  - 
UR  - https://doi.org/10.1071/R97044 
N2  - Early antral follicles 0&#183;5&#8211;0&#183;7 mm in diameter were dissected from bovine ovaries, and oocyte&#8211;cumulus complexes with pieces of parietal granulosa (OCCGs) were then collected from the follicles. The OCCGs containing oocytes of 90&#8211;99 m diameter (94&#183;7 &#177; 2&#183;8 &#181;m, 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&#183;2 &#177; 8&#183;4 &#181;m, significantly larger than that measured before culture (P &#60; 0&#183;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. 
ER  -

