Relationship between sperm mitochondrial membrane potential, sperm motility, and fertility potential

Aim: To analyze the relationship between sperm mitochondrial membrane potential and sperm motility parameters by means of a computer-assisted sperm analyzer (CASA) and in-vitro fertilization rate (%FR). Methods: Semen samples were obtained from 26 men undergoing in vitro fertilization-embryo transfer (IVF-ET). Informed consent was obtained from all men prior to the study. Samples were prepared using wash and swim-up method in HEPES-HTF medium. The sperm motility (%MOT), progressive motility (%PMOT), average path velocity (VAP) (mum/s), straight line velocity (VSL) (mum/s), curvilinear velocity (VCL) (mum/s) and %hyperactivated sperm (%HA), and the %FR were assessed. The samples were incubated in the presence of 2.0 mumol/L of 5,5',6,6' -tetra-chloro-1,1',3, 3'-tetraethylbenzimidazolyl-carbocyanine iodide (JC-1) for 30 min at 37degreesC in air and washed in PBS before flow cytometry (FACSCalibur: Becton Dickinson) analysis. The mitochondrial probe JC-1 was used to identify the mitochondrial membrane potential. The sperm was divided into three populations according to the fluorescence pattern as follows: the high mitochondrial membrane potential group (n=8), the moderate group (n=5), and the low group (n=13). Statistical analysis was performed using Impaired t-test. Results: Significant differences were found between the high and the low groups in %MOT (91.1 +/- 8.5 vs 63.0 +/- 32.7, mean +/-SD), VAP (73.0 +/- 14.2 vs 52.1 +/- 12.5), VCL (127.0 +/- 28.1 vs 87.0 +/- 22.6), %HA (27.3 +/- 23.6 vs 7.2 +/- 9.0) and %FR [73.2 (48/56) vs 59.0 (69/117)]. No significant differences were found in other CASA parameters. Conclusion: When the sperm mitochondrial membrane potential increases, sperm motility parameters and fertility potential will also increase. The JC-1 dye method is useful to predict sperm fertility potential.