Effect of incubation with different concentrations and durations of FSH for in-vitro maturation of murine oocytes

The purpose of the study was to evaluate whether a lower concentration of FSH or 2-h incubation with FSH would improve the outcome of in-vitro maturation of oocytes. The immature oocytes were obtained from FVB mice, and were allocated to four groups and incubated in the maturation media for 24 h. The maturation media were supplemented with 10 mIU/ml FSH for 24 h (group 1), 10 mIU/ml FSH for 2 h (group 2), 75 mIU/ml FSH for 24 h (group 3) or 75 mIU/ml FSH for 2 h (group 4). In each group, half of the in-vitro-matured oocytes were fertilized and cultured to blastocysts and the remaining matured oocytes were analysed for growth differentiation factor (GDF)-9 and bone morphogenetic protein (BMP)-15 mRNA to assess the oocyte quality. The maturation rates and oocyte BMP-15 mRNA concentrations were similar among the four groups. The GDF-9 mRNA concentrations were similar in group 2 and group 4. The fertilization and blastocyst rates were higher in groups 2 and 4 than in groups 1 and 3. It is concluded that 2-h incubation with FSH is better than 24-h incubation in terms of the fertilization rate and blastocyst development.Immature oocyte retrieval followed by in-vitro maturation (IVM) is a feasible alternative to IVF. However, the implantation rate of IVM remains lower than that of traditional IVF. The purpose of the study was to evaluate whether a lower concentration of FSH or 2-h incubation with FSH would improve the outcome of IVM. The Immature oocytes were obtained from mice, and were allocated to four groups and incubated in the maturation media for 24 h. The maturation media were supplemented with 10 mIU/ml FSH for 24 h (group 1), 10 mIU/ml FSH for 2 h (group 2), 75 mIU/ml FSH for 24 h (group 3) or 75 mIU/ml FSH for 2 h (group 4). In each group, half of the in-vitro-matured oocytes were fertilized and cultured to blastocysts and the remaining matured oocytes were analysed for growth differentiation factor (GDF)-9 and bone morphogenetic protein (BMP)-15 mRNA to assess the oocyte quality. The maturation rates and oocyte BMP-15 mRNA concentrations were similar between the four groups. The GDF-9 mRNA concentrations were similar in group 2 and group 4. The fertilization and blastocyst rates were higher in groups 2 and 4 than in groups 1 and 3. We conclude that 2-h incubation with FSH is better than 24-h incubation in terms of the fertilization rate and blastocyst development.