Recombinant Human Follicle Stimulating Hormone and Growth Factors Improve the Meiotic and Developmental Competence of Cat Oocytes

Abstract

In vitro embryo production has proven as potential tool for understanding factors involving developmental biology of embryos. This study aimed at examining the effects of recombinant human follicle stimulating hormone (rhFSH) on meiotic resumption and also on developmental competence of cat oocytes. Experiment 1 studied mRNA expression of luteinizing hormone (LH), follicle stimulating hormone (FSH), epidermal growth factor (EGF) and insulin like growth factor-1 (IGF-1) receptors (R) in cumulus cells. mRNA expression of LH receptor in cumulus cells after oocyte maturation was additionally examined. Experiment 2 examined the effect of different rhFSH concentrations (0.01, 0.05, 0.1 and 1 IU/ml) on meiotic competence. In vitro oocyte maturation without rhFSH served as the control group. The effects of ‘chosen-dose’ rhFSH in combination with rhLH and growth factors (IGF-1 and EGF) on developmental competence were tested in Experiment 3. Cumulus cells surrounding immature oocytes expressed mRNA of FSHR, EGFR and IGF1R, but not LHR. LHR was only expressed after in vitro maturation. All rhFSH concentrations significantly increased maturation rates of cat oocytes in a dose-dependent manner when compared with the control group (p<0.05). The 0.1 IU/ml rhFSH was selected for Experiment 3 due to its efficacy. The developmental competence of cat oocytes was not affected by rhLH supplementation (p>0.05), but IGF-1 and EGF significantly promoted cleavage and blastocyst formation rates compared with rhFSH and rhFSH plus rhLH (p<0.05). It is concluded that cumulus cells express FSHR, LHR, EGFR and IGF1R. However, LHR mRNA was only expressed after in vitro maturation. Efficacy of FSH in meiotic resumption is in a dose-dependent manner. The combination of rhFSH and growth factors (IGF-1 or EGF) best improves cytoplasmic maturation of feline oocytes in terms of cleavage and blastocyst rates.