Growth factors and components for extracellular proteolysis are differentially expressed during in vitro maturation of bovine cumulus-oocyte complexes.
In the present study, the time-dependent collagenolytic potential and mRNA transcription of extracellular matrix (ECM)-degrading components, transforming growth factor beta1 (TGFbeta1), and both basic fibroblast growth factor (bFGF) and FGF receptors (FGFR) in bovine cumulus-oocyte complexes (COCs) were investigated during 24 h of in vitro maturation (IVM). COCs were collected from 2- to 6-mm follicles, cultured in maturation medium, and sequentially removed at 3-h intervals for analysis. From 285 oocytes matured under these conditions, 114 (40.0%) developed to blastocysts on Day 9 after fertilization. Gelatin zymograms revealed protease activity at about 55 kDa for COCs matured for at least 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 metalloproteinases 1 (TIMP1), as well as TGFbeta1, bFGF, and FGFR, were detected during IVM in a factor-specific pattern: all transcript levels found at COC 0 generally increased after 3 h of maturation and either remained 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 factors compared to uPA, MMP1, and FGFR. Our results suggest a finely tuned extracellular proteolysis during IVM of bovine COCs, for which the concerted action of modulating growth factors like bFGF and TGFbeta1 may be essential.
Bieser
B
B
Institute of Physiology, Technical University München-Weihenstephan, 85350 Freising, Germany.
Stojkovic
M
M
Wolf
E
E
Meyer
H
H
Einspanier
R
R
D000818:Animals; D002417:Cattle; D005260:Female; D006133:Growth Substances / Q000096:biosynthesis* / Q000235:genetics; D066298:In Vitro Techniques; D009865:Oocytes / Q000201:enzymology / Q000254:growth & development* / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D017978:Receptors, Growth Factor / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic
D006133:Growth Substances; D012333:RNA, Messenger; D017978:Receptors, Growth Factor; D010447:Peptide Hydrolases