Responsiveness of @entity291 cumulus-oocyte-complexes (COC) to porcine and recombinant XXXX FSH, and the effect of COC quality on gonadotropin receptor and Cx43 marker gene mRNAs during maturation in vitro.

@entity1 @entity44503 @entity13509 @entity291 @entity942
Substantially less development to the blastocyst stage occurs in vitro than in vivo and this may be due to @entity942 . Although a large proportion of @entity291 oocytes undergo spontaneous nuclear maturation, less is known about requirements for proper cytoplasmic maturation. Commonly, supraphysiological concentrations of FSH and LH are added to maturation media to improve cumulus expansion, fertilization and embryonic development. Therefore, various concentrations of porcine FSH (pFSH) and recombinant @entity1 FSH (rhFSH) were investigated for their effect on @entity291 cumulus expansion in vitro. Expression of @entity44503 , LHr and @entity13509 mRNAs was determined in cumulus-oocyte complexes to determine whether they would be useful markers of oocyte competence. In serum-free media, only 1000 ng/ml pFSH induced marked cumulus expansion, but the effect of 100 ng/ml pFSH was amplified in the presence of 10% serum. In contrast, cumulus expansion occurred with 1 ng/ml rhFSH in the absence of serum. @entity44503 mRNA was highest at 0-6 h of maturation, then abundance decreased. Similarly, @entity13509 mRNA expression was highest from 0-6 h but decreased by 24 h of maturation. However, the relative abundance of LHr mRNA did not change from 6-24 h of maturation. Decreased levels of @entity44503 , LHr and @entity13509 mRNAs were detected in COCs of poorer quality. In conclusion, expansion of @entity291 cumulus occurred at low doses of rhFSH in serum-free media. In summary, @entity44503 , LHr and @entity13509 mRNA abundance reflects COC quality and @entity44503 and @entity13509 mRNA expression changes during in vitro maturation; these genes may be useful markers of oocyte developmental competence.
