The expression of matrix metalloproteinase-9 in human follicular fluid is associated with in vitro fertilisation pregnancy

Objective To investigate the role of matrix metalloproteinase-9 (MMP-9) in the pre-ovulatory follicular fluid and culture media during in vitro fertilisation (IVF) cycle and to develop the zymographic pre-diagnosis marker for successful implantation and pregnancy in human IVF. Design Controlled clinical study. Setting IVF Laboratory, Women's Hospital Infertility Clinic and Dongguk University, Korea. Methods Women undergoing in vitro fertilisation treatment. Main outcome measures Experiments were designed for controlled clinical study with women undergoing IVF treatment. MMP-9 expressions in follicular fluid and culture media samples that had been collected during transvaginal oocyte retrieval were measured using zymography. MMP-9 activities and expressions were strongly correlated to a higher rate of fertilisation and pregnancy. Main outcome measures Fertilisation rates and ultrasonic evidence of intrauterine pregnancy by four weeks after embryo transfer. Result MMP-9 activity was significantly higher in the pregnant group than in the non-pregnant group (P < 0.01). In contrast, MMP-2 activity was present in the follicular fluid and culture media of all women, and no difference in its expressions was found between the pregnant and non-pregnant groups. No correlation was found between the MMP-9 expression in follicular fluid and culture media and the fertilisation rates. Conclusion The expression of MMP-9 in the follicular fluid and culture media is a prerequisite for successful pregnancy in IVF cycle. The zymography of MMP-9 activity in follicular fluids of human and culture media was developed as a pre-diagnostic method and zymographic diagnosis marker for successful fertilisation, implantation and pregnancy in human IVF.