Comparison of techniques for selection of motile spermatozoa.

Procedures to separate motile sperm with high rates of recovery may have clinical application in in vitro fertilization and intrauterine insemination in increasing the probability of fertilization by a normal sperm and subsequent normal embryonic development. A two-step continuous Percoll gradient was an effective means of separating motile sperm which also had enhanced ability to penetrate zona-free hamster ova. However, the requirement for a high-speed centrifuge and rotor makes the procedure impractical in many cases. A one-step discontinuous Percoll gradient was also effective in separating a population of motile sperm. Comparison of the discontinuous Percoll gradient with other techniques for separation of motile sperm indicated the discontinuous Percoll gradient had advantages in terms of recovery, enhancement of motility, and increased ability to penetrate zona-free hamster ova. The velocity of selected sperm was not significantly different among techniques. The one-step discontinuous Percoll gradient appears to have value both for increasing homogeneity of human sperm populations used for basic research and in clinical practice for male subfertility.