R. John Aitken

An analysis of sperm function in cases of unexplained infertility: conventional criteria, movement characteristics, and fertilizing capacity *

A detailed analysis of semen quality was carried out in 85 couples with unexplained infertility by the use of conventional criteria of semen analysis, time-exposure photomicrography, and the zona-free hamster egg penetration test. According to the latter, 34.1% of the male partners exhibited evidence of defective sperm function, although only 4% of these patients were devoid of any demonstrable fertilizing capacity. Of the conventional parameters of semen analysis examined, the most revealing was the morphologic character of the sperm, which was significantly poorer (P less than 0.001) in the group with unexplained infertility than in the normal fertile control group and also showed a significant relationship (P less than 0.001) with the presence of subnormal fertilizing capacity in the hamster egg assay. A majority of movement characteristics measured by time-exposure photomicrography were significantly depressed in the group with unexplained infertility, compared with the normal fertile control group. In addition, certain of the movement characteristics investigated were significantly related to the fertilizing capacity of the spermatozoa; and, in this respect, a progressive swimming speed (greater than 25 micrometers/sec), a straight swimming mode of progression, and a small amplitude of lateral head displacement (Ah) all appeared to be important qualities.

Protective effect of antioxidants on the impairment of sperm motility by activated polymorphonuclear leukocytes

OBJECTIVE To test the ability of antioxidants to reduce the loss of sperm motility caused by reactive oxygen species generated by polymorphonuclear leukocytes (PML). DESIGN Standardized preparations of leukocyte-contaminated semen were created by suspending known concentrations of purified spermatozoa and PML in seminal plasma. After the stimulation of reactive oxygen species generation with phorbol ester, the spermatozoa were washed and incubated in culture medium before an analysis of their movement. The ability of antioxidants to counteract the free radical-induced loss of sperm motility observed under these circumstances was assessed. SETTING An institutional research laboratory. PARTICIPANTS The semen was obtained from normal volunteers. INTERVENTIONS The following were tested: vitamins C and E, dimethylsulfoxide, catalase, hypotaurine, N-acetylcysteine, and reduced glutathione. MAIN OUTCOME MEASURES Reactive oxygen species generation was monitored by luminol-dependent chemiluminescence. Sperm motility was assessed manually and by computer-aided semen analysis. RESULTS Consistent impairment of sperm motility and average path velocity was observed in the presence of activated PML. This effect was reduced by the concomitant presence of glutathione, N-acetylcysteine, hypotaurine, and catalase. CONCLUSION Antioxidants can protect against the damaging effect of leukocyte-derived reactive oxygen species on sperm movement and may be of clinical value in assisted conception procedures.

The correlates of fertilizing capacity in normal fertile men

An investigation has been carried out in normal fertile men on the correlates of fertilizing capacity as defined by the zona-free hamster egg penetration test. The results demonstrate that the apparent fertility of these men is compatible with a wide range of intrinsic sperm quality as reflected by penetration rates ranging from 14% to 90% and differences in the minimum concentration of motile spermatozoa required to initiate penetration. These differences in sperm function could not be correlated with any of the conventional parameters of semen analysis or any of a large number of sperm movement characteristics analyzed by time-exposure photomicrography, with two exceptions: (1) the percentage of progressively (greater than 25 micron/sec) motile spermatozoa exhibiting an amplitude of lateral head displacement (Ah) of less than 10 micron, which was positively correlated with penetrating capacity (P less than 0.01), and (2) the percentage of progressively (less than 25 micron/sec) motile spermatozoa exhibiting an Ah of greater than 10 micron, which was negatively correlated with penetration rate (P less than 0.05). The information obtained in this study should provide a useful basis against which to compare the properties of spermatozoa in cases of suspected infertility.

Epithelial cell coculture and the induction of sperm capacitation

OBJECTIVE To investigate the influence of cultured human oviductal epithelial cells on the movement characteristics of human spermatozoa. DESIGN Human spermatozoa were cultured with monolayers of human epithelial or Vero cells or conditioned media derived from these cell types. The viability and movement characteristics of the cells was subsequently analyzed at 4, 24, and 48 hours. SETTING University hospital and Medical Research Council laboratories. PATIENTS, PARTICIPANTS Volunteer donors. MAIN OUTCOME MEASURES Movement characteristics of human spermatozoa. RESULTS The presence of both Vero and oviductal epithelial cells, but not conditioned media, had a general promoting effect on sperm survival, significantly enhancing sperm viability and motility for up to 48 hours of culture. In addition, the presence of oviductal epithelial cells had a specific, significant stimulatory effect on sperm capacitation, enhancing the incidence of hyperactivated motility after 4, 24, and 48 hours of culture. Significantly, this effect was not observed with cocultures containing Vero cells. CONCLUSIONS The coincubation of human spermatozoa with human oviductal epithelial cells provides a convenient system for the induction and analysis of sperm capacitation.

Suppression of sperm function by depot medroxyprogesterone acetate and testosterone enanthate in steroid male contraception

Abstract Ten normal men were given three monthly intramuscular injections of 200 mg of depot medroxyprogesterone acetate (MPA) and 250 mg of testosterone (T) enanthate. Six men became azoospermic, while four remained oligozoospermic, with a mean sperm density of 1.5 ± 0.3 standard error of the mean million/mi. Zona-free hamster oocyte penetration was abolished in all oligozoospermic samples at the end of treatment. Twenty of the 21 oligozoospermic samples yielding at least 0.6 to 5.0 million motile spermatozoa showed a complete absence of oocyte penetration. Semen parameters returned to normal, although some took up to 12 months. These findings demonstrated an antifertility action of MP A and T enanthate on the functional capacity of residual spermatozoa and support the view that extreme oligozoospermia may be a tenable target for reversible steroid male contraception.

The value of adenosine triphosphate (ATP) measurements in assessing the fertilizing ability of human spermatozoa

A study was undertaken to examine the relationship between adenosine triphosphate (ATP) levels and the fertilizing capacity of human spermatozoa in vitro and in vivo. The concentration of ATP in semen was found to be positively correlated with the ability of sperm to fuse with zona-free hamster oocytes. However, it was also demonstrated that a large part of this relationship depends upon the relationship between semen ATP concentrations and sperm number. Measurements of ATP levels in cryostored ejaculates used in an artificial insemination by donor program revealed that such measurements were not able to distinguish fertile from infertile ejaculates. However, among fertile donors, ATP levels did seem to contribute useful information on relative fertility. It is concluded that ATP measurement has a limited role in the laboratory evaluation of sperm function.

Field trial of a diluent for the transportation of human semen at ambient temperatures

OBJECTIVE To examine the ability of a citrate-yolk buffer extender to preserve human semen samples at ambient temperatures over a 25- to 30-hour period. DESIGN Human semen samples were diluted 1:1 with citrate-yolk buffer or homologous seminal plasma and transported at ambient temperature between two distant locations (London to Edinburgh, United Kingdom). Various criteria of semen quality then were assessed before and after 25 to 30 hours storage and transportation in these diluents. SETTING An institutional research laboratory and a private fertility clinic. PATIENT(S) Samples were provided by 21 donors of unknown fertility and 7 asthenozoospermic patients. INTERVENTION(S) The diluent used to preserve human semen comprised an egg yolk buffer supplemented with fructose and citrate. MAIN OUTCOME MEASURE(S) Aspects of semen quality assessed included movement, hyaluronate penetration, viability, acrosome reaction, and reactive oxygen species generation. RESULT(S) The deterioration of semen quality at ambient temperatures could be prevented by the presence of citrate-yolk buffer, permitting the accurate analysis of oxidative stress and human sperm function, 25 to 30 hours postejaculation. CONCLUSION(S) Citrate-yolk buffer offers considerable promise as a medium for the ambient temperature storage and transportation of human semen.