Portal de Periódicos da CAPES

Sperm Motility

1980; Elsevier BV; Volume: 34; Issue: 3 Linguagem: Inglês

10.1016/s0015-0282(16)44949-6

1556-5653

Edward E. Wallach, Richard D. Amelar, Lawrence Dubin, Cy Schoenfeld,

Assisted Reproductive Technology and Twin Pregnancy

Current literature dealing with sperm motility is reviewed. Laboratory observation has led to the hypothesis that the sperm tail moves when the microtubules, powered by adenosine triphosphate (ATP), slide past one another, moving by means of their dynein arms, which are actual molecules of ATP activity. This sliding microtubule hypothesis is considered to explain the motility of the 9+2 sperm tails and all cilia and flagella. The clinical usefulness of determinations of various glycosidases in semen has been assessed in recent years. The neutral alpha-glycosiderase specific activity of sperm has been correlated with the percentage motility. It is postulated that an abnormal function of the epididymis may be related to decreased production of alpha-glucosidases. The subjective nature of visual assessment of motility is a persistent problem for researchers. Objective appraisal is hampered by variation in the appraisals of different researchers and striking, unexplained differences in motility in successive visits. Quantitative methods that can provide reproducible information on overall motility and percentage of motile sperm and can distinguish the speed of progression from ineffective vibrating and circling motions are not yet available to clinicians. Factual knowledge of the process of sperm maturation in the epididymis and the special quality of the environment in the epididymis that supports maturation or sperm storage is lacking. Various groups of compounds have been used to stimulate the in vitro motility of sperm, including methyl xanthines, nucleotides, carnitine and acetylcarnitine, arginine, and kallikrein. Sperm washing will occasionally enhance motility. There is agreement that sperm lose their motility within 15 days after vasectomy. The split-ejaculate method has demonstrated that the distribution of sperm cells is not uniform throughout the ejaculatory process. Insemination with the 1st portion of the split ejaculate has been effective in achieving pregnancy in infertile couples. Therapy for increasing sperm motility includes low dosage androgen and human chorionic gonadotropin. Research has been directed at improving the survival of motile sperm during the process of freezing, storing, and thawing human semen. However, storage of fertile semen does not guarantee future fertility.