Sperm matrix metalloproteinase-2 activity increased in pregnant couples treated with intrauterine insemination: a prospective case control study.

ABSTRACT

Matrix metalloproteinase-2 (MMP2) and matrix metalloproteinase-9 (MMP9) have an important role in the reproductive system and in the fertilisation process. The aim of this study was to investigate the MMP2 and MMP9 activity in semen and their association with the pregnancy rate, semen parameters and seminal plasma oxidative stress parameters in couples who were treated with intrauterine insemination (IUI). The semen specimens were obtained from 60 men who attended with their spouse for the IUI in the infertility unit. A controlled ovarian stimulation was performed with clomiphene citrate in IUI cycles. Women with positive pregnancies were recorded (n = 29). The results showed the activity of sperm MMP2 and seminal plasma MMP9 was significantly higher in the pregnant group, compared to the non-pregnant group (p < .05). There was a correlation between the sperm MMP2 activity and the total thiol group (TTG) (r = 0.276, p < .05) and the total antioxidant capacity (TAC) of seminal plasma (r = 0.304, p < .05). The sperm MMP9 showed a positive correlation with the seminal plasma TAC (r = 0.330, p < .05) and an inverse correlation with the lipid peroxidation (LP) of seminal plasma (r = -304, p< 0.05). In addition, the seminal plasma MMP2 activity was correlated to sperm viability (r = 0.266, p< .05) and the TTG of seminal plasma (r = 0.298, p < .05). The MMP2 activity in the sperm may be an important factor for determining the pregnancy rate after IUI. Impact statement What is already known on this subject? Previous studies have reported that the fusion between the sperm and zona pellucida required the activity of matrix metalloproteinase 2 (MMP2), whereas the inhibition of MMP2 can significantly decrease the in vitro fertilisation (IVF) rate. What do the results of this study add? This study has identified that the sperm MMP2 activity was significantly higher in the pregnant couples in comparison with the non-pregnant couples, who treated with intrauterine insemination (IUI). The findings showed there was a correlation between sperm MMP2 activity and the total thiol group (TTG) and the total antioxidant capacity (TAC) of the seminal plasma. What are the implications of these findings for clinical practice and/or further research? MMP2 activity in the sperm could influence the IUI outcome and it is an important factor for IUI success.