Sperm quality improvement in cryopreserved human semen

We determined if separation of spermatozoa (washed) on a discontinuous colloidal suspension of silica (Percoll) density gradient before cryopreservation improves post-thaw motility compared to an unprocessed (raw) cryopreserved sample.

Ten normal healthy volunteers recruited into the andrology laboratory donor program were studied. Raw and washed cryopreserved spermatozoa were compared for loss of motility with time, motion characteristics, viability and membrane integrity after incubation for 1, 6 and 24 hours. Within group comparisons were made to baseline measurements (0 hours before incubation).

Raw and washed cryopreserved spermatozoa showed statistically significant decreases in motility and other motion characteristics after thawing. There were significant decreases in motility and other motion characteristics after incubation periods of 1, 6 and 24 hours, and significant decreases in viability and membrane integrity at 6 and 24 hours in the unprocessed spermatozoa. Although, motility and motion characteristics of washed samples decreased significantly with longer incubation periods, loss of motility with time (longevity) was greater in raw samples. Washed samples retained greater sperm motility for up to 24 hours (p < 0.03).

Specimens prepared by Percoll separation techniques before freezing offer the possibility of selecting spermatozoa that retain motility for up to 24 hours. This finding can be of benefit for couples undergoing intrauterine insemination to achieve pregnancy.