[Correlation of sperm mitochondrial membrane potential with semen parameters and outcomes of in vitro fertilization]

To investigate the correlation of sperm mitochondrial membrane potential (MMP) with routine semen parameters and the effect of MMP on the outcomes of in vitro fertilization (IVF).

We retrospectively analyzed the clinical data on 727 IVF cycles, including 231 fresh transplantation cycles, in our hospital from November 2018 to October 2019. According to the MMP level determined by JC-1 staining and flow cytometry, we divided the patients into a low MMP (≤52%) and a high MMP (> 52%) group and compared the rates of fertilization, clinical pregnancy, abortion and live birth between the two groups. Meanwhile, we analyzed the correlation of sperm MMP with the semen volume, sperm concentration, total sperm count, total sperm motility, percentages of progressively motile sperm (PMS) and morphologically normal sperm (MNS), and sperm DNA fragmentation index (DFI).

The fertilization rate was significantly higher in the high MMP than in the low MMP group (85.3% ［2 211/2 592］ vs 81.7% ［3 910/4 785］, P < 0.01), and so were the rates of clinical pregnancy (50.00% ［41/82］ vs 48.32% ［72/149］, P < 0.05) and live birth (43.90%［36/82］ vs 40.94% ［61/149］, P < 0.05), while the abortion rate was lower in the former than in the latter group (12.20% ［5/41］ vs 15.28% ［11/72］, P > 0.05). Statistically significant differences were observed between the two groups in sperm concentration, total sperm motility, percentages of PMS and MNS, and sperm DFI (P< 0.05), but not in the semen volume and total sperm count (P > 0.05). Sperm MMP was found correlated positively with sperm concentration (r = 0.11, P < 0.05), total sperm motility (r = 0.304, P < 0.01) and percentages of PMS (r = 288, P < 0.01) and MNS (r = 458, P < 0.01) but negatively with sperm DFI (r = 0.387, P < 0.01).

The level of sperm MMP is related to decreased sperm motility, increased sperm abnormality, elevated sperm DFI and reduced IVF rate. It is also an important index for sperm function evaluation and, together with routine semen parameters, helps to comprehensively evaluate and optimize the assisted pregnancy program of infertile men in assisted reproduction technology.