Transforming growth factorβ1 level in follicular fluid undergoing ovarian stimulation and in vitro fertilization correlates to oocyte maturation and pregnancy

Abstract

Objective: The follicular fluid plays an important biological role in folliculogenesis, oocyte maturation and ovulation. In the human follicle, TGF β1 had been found to be produced in both theca and granulosa cells in culture. We therefore hypothesized that TGF β1 might be involved in the regulation of follicular growth and oocyte maturation together with sex hormones, and be correlated to IVF outcome. Our purpose is to investigate the role of transforming growth factor1(TGFβ1) and reproductive hormones in the preovulatory follicular fluid during ovulation stimulation cycles. Design: Enzyme immunoassay was used to determine TGFβ1, estrodial (E2), progesterone(P) and luteinizing hormone(LH) concentrations in follicular fluid. The maturity and fertilization of the corresponding oocyte and clinical pregnancy were analyzed. Materials and Methods: Follicular fluids (FF) and their matched oocytes were obtained from follicles of 96 women undergoing ovulation stimulation and IVF treatment. TGF-β1, E2, P, and LH concentrations in follicular fluid samples that had been collected during transvaginal oocyte retrieval were measured using an enzyme immunoassay. The maturity and fertilization of the corresponding oocyte were followed. Clinical pregnancies were confirmed by ultrasound at 4 weeks after embryo transfer. Results: It was found TGF β1, P and LH concentrations were significantly higher at mature oocytes group compared to immature group (2824.4±1414.4pg/ml, 3837.1±942.8 ng/ml and 0.71±0.35 mIU/ml versus 2015.0±1191.7pg/ml, 3188.1±617.4 ng/ml and 0.54±0.21 mIU/ml, respectively, P<0.05). The mean concentration of TGF β1, E2 and P in fertilized group are higher than in non-fertilized group (2845.7±1476.7 pg/ml, 3832.0±995.2 ng/ml and 0.73±0.35 mIU/ml verses 2044.4±1111.1 pg/ml, 3401.6±607.6 ng/ml and 0.53±0.21 mIU/ml respectively, P<0.05). The mean concentrations of TGF β1 and LH in FF in pregnancy group was significantly higher than that in non-pregnancy group (3631.4±1426.3 pg/ml and 0.74±0.25miu/ml versus 2189.2±1180.4 pg/ml and 0.52±0.29miu/ml respectively,P<0.05). No significant difference of level of E2 and P in the follicular fluid were found between the pregnant and non-pregnant groups. Conclusion: Increase of TGFβ1 and LH in the follicular fluid appears to be associated with a positive outcome in IVF treatment; TGFβ1 in FF maybe related to the oocyte quality and development potential.