PARENT SESSION
GAMETE BIOLOGY AND GAMETOGENESIS - A

Monday, August 2, 2004
10:30 AM–12:30 PM
Buchanan Courtyard

(153) EFFECT OF CUMULUS CELLS ON PLASMINOGEN ACTIVITY AND OOCYTE MATURATION IN VITRO IN THE PIG.

Park, Choon-Keun¹, Ann, Ji-Young¹, Sa, Soo-Jin¹, Choi, Sun-Ho², Cheong, Hee-Tae¹, Yang, Boo-Keun¹, Kim, Choung-Ik¹, ¹ Division of Animal Resource, Chunchon, Kangwon-Do, Korea² National Livestock Research Institute, Cheonan, Chungcheongnam-Do, Korea

ABSTRACT- Plasminogen activators (PAs) are serine proteases, known to be secreased by a large number of cell types. PAs are claimed to play a role in variety of physiologic processess, including fibrinolysis, ovulation, mammary involution, implantation and fertilization. The present study was designed to investigate whether PAs are produced by porcine oocytes during maturation in vitro with various conditions. PA activities in porcine oocytes were quantified using SDS-PAGE, casein-agar zymography, and densitometry. When oocytes collected from different sizes in follicular diameter were cultured, the proportions of oocytes matured to metaphase-II stage were higher in 6-10 mm (77%) than 2-6 mm (56%) and 1-2 mm (36%) in follicular diameter. The maturation rates were also significantly (P<0.05) higher in medium with that than without fetal bovine serum during culture of oocytes collected from different follicular diameter. However, PAs activities from follicular fluids and oocytes without cumulus cells were not detected. In another experiment, when oocytes with cumulus cells were cultured for 24 and 48 h, the proportions of oocytes matured were significantly (P<0.05) higher than in oocytes without cumulus cells. The tissue type plasminogen (tPA) were detected in oocytes with cumulus cells regardless of presence of fetal bovine serum during oocyte culture. These results suggest that tPA is produced by cumulus cells of porcine oocytes during maturation in vitro. Cumulus cells play an essential role on oocyte maturation in vitro and production of tPA by oocytes. This work was supported by grant No. R01-2003-000-10500-0 from Basic Research Program of the Korea Science & Engineering Foundation.

KEY WORDS: oocytes maturation, pig, cumulus cells , plasminogen activity