Differences in collagen expression in cumulus cells after exposure to highly purified menotropin or recombinant follicle-stimulating hormone in a mouse follicle culture model.
Extracellular matrix (ECM) formation by cumulus cells is an important process that determines fertilization and embryo quality. Several collagen types are present in the ovarian follicular ECM and are related to proliferation, steroidogenesis, and luteinization. In vitro mouse follicles can optimally grow and provide developmentally competent oocytes with 10 IU/L recombinant follicle-stimulating hormone (rFSH). As a model for superovulation, experiments with 100 IU/L rFSH or 100 IU/L highly purified menotropin (HP-hMG) exposure during antral growth were undertaken. Col4a1, Col4a2, and Col6a2 expression levels were analyzed at three time points during antral growth and at a 4-h interval up to 16 h after ovulation induction using quantitative PCR. The presence and induction of the collagen mRNA and protein were confirmed in cumulus from in vivo- and in vitro-grown follicles, and TGFBs 1 and 2 were assayed as potential regulators. The study revealed that exposure to 100 IU/L FSH, as in both superovulation conditions, significantly influenced the follicle morphology and slowed down nuclear maturation and mucification (P < 0.05). This coincided with an increased expression of the three collagens in the cumulus-oocyte complex at the end of antral growth and in the first hours following the ovulatory dose of human chorionic gonadotropin (P < 0.05). The increased expression might reflect a differentiation but is most likely due to a precocious luteinization of the cumulus. Growth in HP-hMG resulted in higher Tgfb1 mRNA and protein levels, fewer COCs with an increased collagen expression and with a more synchronous nuclear maturation. This suggests that the presence of luteinizing hormone activity tempered the effect of the elevated FSH dose.
Adriaenssens
Tom
T
Vrije Universiteit Brussel, Brussels, Belgium. Tom.Adriaenssens@UZBrussel.be
Mazoyer
Claire
C
Segers
Ingrid
I
Wathlet
Sandra
S
Smitz
Johan
J
D000818:Animals; D001483:Base Sequence; D003094:Collagen / Q000235:genetics* / Q000378:metabolism*; D024141:Collagen Type IV / Q000235:genetics / Q000378:metabolism; D024142:Collagen Type VI / Q000235:genetics / Q000378:metabolism; D054885:Cumulus Cells / Q000187:drug effects* / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D008596:Menotropins / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D006080:Ovarian Follicle / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D046509:Tissue Culture Techniques; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism; D053781:Transforming Growth Factor beta2 / Q000235:genetics / Q000378:metabolism
D024141:Collagen Type IV; D024142:Collagen Type VI; D017931:DNA Primers; D012333:RNA, Messenger; D011994:Recombinant Proteins; C508961:Tgfb1 protein, mouse; C509042:Tgfb2 protein, mouse; D053773:Transforming Growth Factor beta1; D053781:Transforming Growth Factor beta2; D008596:Menotropins; D005640:Follicle Stimulating Hormone; D003094:Collagen