B. Bieser et al., GROWTH-FACTORS AND COMPONENTS FOR EXTRACELLULAR PROTEOLYSIS ARE DIFFERENTIALLY EXPRESSED DURING IN-VITRO MATURATION OF BOVINE CUMULUS-OOCYTE COMPLEXES, Biology of reproduction, 59(4), 1998, pp. 801-806
In the present study, the time-dependent collagenolytic potential and
mRNA transcription of extracellular matrix (ECM)-degrading components,
transforming growth factor beta 1 (TGF beta 1), and both basic fibrob
last growth factor (bFGF) and FGF receptors (FGFR) in bovine cumulus-o
ocyte complexes (COCs) were investigated during 24 h of in vitro matur
ation (IVM). COCs were collected from 2- to 6-mm follicles, cultured i
n maturation medium, and sequentially removed at 3-h intervals for ana
lysis. From 285 oocytes matured under these conditions, 114 (40.0%) de
veloped to blastocysts on Day 9 after fertilization. Gelatin zymograms
revealed protease activity at about 55 kDa for COCs matured for at le
ast 3 h and two additional proteolytic zones at about 70 kDa after at
least 9 h of IVM. The mRNAs of ECM-degrading components urokinase-type
plasminogen activator (uPA), plasminogen activator inhibitor 1 (PAI1)
, matrix metalloproteinase 1 (MMP1), and tissue inhibitor of metallopr
oteinases 1 (TIMP1), as well as TGF beta 1, bFGF, and FGFR, were detec
ted during IVM in a factor-specific pattern: all transcript levels fou
nd at COC 0 generally increased after 3 h of maturation and either rem
ained high or decreased thereafter. On the basis of the chosen reverse
transcription-polymerase chain reaction technique, one could suggest
relative higher mRNA concentrations for TIMP1, PAI1, and both growth f
actors compared to uPA, MMP1, and FGFR. Our results suggest a finely t
uned extracellular proteolysis during IVM of bovine COCs, for which th
e concerted action of modulating growth factors like bFGF and TGF beta
1 may be essential.