Effects of growth factors and granulosa cell co-culture on in-vitro maturation of oocytes

The maturation medium for in-vitro oocyte maturation is usually supplemented with serum. However, supplementation with serum from pregnant women adversely affects the outcome of in-vitro maturation. The purpose of the study was to assess if growth factors or granulosa cell co-culture could overcome the adverse effects of pregnant women's serum. The basal maturation medium consisted of TCM199, 75 mIU/ml human menopausal gonadotrophin (HMG), 0.2 mmol/l pyruvate, and 10% serum. The maturation medium for control 1 contained fertile women's serum. The maturation medium for control 2 contained pregnant women's serum. The maturation media for the study groups consisted of medium for control 2, with the addition of EGF, IGF-I, activin, TGFβ or granulosa cell co-culture. Immature oocytes were obtained from FVB mice, and the experiment was repeated six times. After maturation, the oocytes were fertilized and cultured to blastocysts, and the cumulus cells were analysed for apoptosis. The maturation, fertilization and blastocyst rates of the control 2 group were significantly lower than those of control 1 group (P <0.05). Addition of EGF, IGF-1, activin, TGFβ or granulosa cell co-culture could not improve the outcome of in-vitro maturation. Cumulus cell proliferation was inhibited by pregnant women's serum. Apoptosis of cumulus cell was not related to in-vitro oocyte maturation and subsequent embryo development.