A comparison of swim-down and swim-up methods for the extraction of high motility sperm

Filtration of human seminal specimens using LeukoSorb leukocyte-retention medium

OBJECTIVE

To compare LeukoSorb filtration with Percoll centrifugation in preparing sperm.

METHODS

Each of 26 human seminal specimens were analyzed before and after two preparation methods.

RESULTS

In normospermic specimens (n = 11), LeukoSorb produced higher results than Percoll did with regard to mean percentage of motility (72.7% vs 59.2%), total swollen sperm in a hypo-osmotic swelling test (84.8% vs 59.0%), (g)-type swollen sperm (37.8% vs 23.4%) and tail abnormality (20.4% vs 10.1%). In asthenospermic specimens (n = 15), LeukoSorb produced higher results than Percoll did with regard to mean percentage of motile sperm recovery (22.2% vs 10.1%), motility (46.9% vs 23.2%), viability (75.6% vs 54.7%), total swollen sperm (84.8% vs 59.0%) and tail abnormality (42.2% vs 24.3%), although the mean percentage of head abnormality was lower with LeukoSorb than with Percoll (30.6% vs 40.2%) vs 40.2%). In pyospermic specimens (n = 10), the mean concentration of round cells after LeukoSorb decreased significantly more than with Percoll (p = 0.029). The filtration time correlated with the total sperm concentration.

CONCLUSION

LeukoSorb filtration is useful for preparing asthenospermic and pyospermic seminal specimens.

Investigation in real time of the effect of gravitation on human spermatozoa and their tendency to swim-up and swim-down

To investigate in real time if and how natural gravity affects rates of swim-up and swim-down of human spermatozoa, samples of motile or immobilized spermatozoa in a sealed mini-chamber were placed vertically on a 90 degrees tilted microscope. The mode of their sedimentation, as well as the difference in the rate of their swimming up and down, were observed directly over 30 min and analysed from photomicrographs. Under the influence of natural gravity force, most immobilized spermatozoa turned their heads down in about 5 min and then sank slowly at an average speed of 0.2 mu/s. The number of motile spermatozoa that swam down was 5-6 times more than those swimming up. It can be implied that in spite of the mild force exerted by 1 g on suspended spermatozoa in comparison to the high g force obtained by centrifugation, the overall effect of gravity on the rate of swimming up or down becomes dominant. Gravity causes the sperm heads to turn downward after which the oriented spermatozoa continue to move down by their own tail movements, causing accumulation of motile spermatozoa at the bottom. This may explain why in some recent studies swim-down was superior to the swim-up procedure during sperm separation by self-migration.

Simultaneous swim-up/swim-down of sperm in assisted reproduction procedures

PURPOSE

High-quality motile human spermatozoa were obtained following treatment of semen by simultaneous swim-up into medium and swim-down into an isotonic 40% Percoll solution.

RESULTS

This procedure was significantly better than the swim-up method and comparable to discontinuous Percoll gradient centrifugation. Recovery rates of motile sperm were 35% for swim-up, 65% for Percoll gradient centrifugation, and 73% for swim-up/swim-down.

CONCLUSION

The swim-down sperm was inferior to the swim-up sperm in its upward migration capacity but superior in morphology. Spermatozoa obtained by the swim-up/swim-down procedure demonstrated fertilizing ability in IVF, and clinical pregnancies were established. The simultaneous swim-up/swim-down procedure offers an alternative efficient method of simple separation of high-quality motile sperm for various assisted reproduction techniques.