Effects of magnetic-activated cell sorting on sperm motility and cryosurvival rates.

OBJECTIVE: To evaluate the effect of magnetic-activated cell sorting in cryopreservation-thawing protocols on sperm motility and cryosurvival rate.
DESIGN: Prospective-controlled study.
SETTING: Andrology department at a university-based medical institution. PATIENT(S): Ten healthy volunteer sperm donors. INTERVENTION(S): Sperm populations were separated using annexin-V magnetic-activated cell sorting before and after the cryopreservation-thawing process. MAIN OUTCOME MEASURE(S): Sperm motility and cryosurvival rate. RESULT(S): Annexin-negative sperm separated by magnetic-activated cell sorting had statistically significantly higher motility following cryopreservation-thawing than sperm that were not separated. Similarly, annexin-negative spermatozoa also had higher cryosurvival rate than sperm cryopreserved without magnetic-activated cell sorting and sperm that were annexin-positive. CONCLUSION(S): Superparamagnetic annexin V-conjugated microbeads can separate spermatozoa with externalized phosphatidylserine, which is considered one of the early features of late apoptosis. The separation of a distinctive population of nonapoptotic spermatozoa with intact membranes may optimize the cryopreservation-thawing outcome. Magnetic-activated cell sorting using annexin-V microbeads enhances sperm motility and cryosurvival rates following cryopreservation.