Tests of sperm function for evaluation of the male: Penetrak **Penetrak, Serono Laboratories, Norwell, Massachusetts. and Tru-Trax ††Tru-Trax, Humagen, Charlottesville, Virginia. ‡‡Presented at the 87th Annual Meeting of the American Urologie Association, Washington D.C., May 10 to 11, 1992

Is fine morphology of the human sperm nuclei affected by in vitro incubation at 37°C?

OBJECTIVE

Incubation of ejaculated spermatozoa at 37 degrees C is recommended for IVF-intracytoplasmic sperm injection. Preselection of sperm cells with morphologically normal nuclei before microinjection, adapted in our laboratory, is usually a time-consuming procedure. Therefore, we aimed to verify whether incubation at 37 degrees C could affect the morphologic integrity of sperm nuclei.

DESIGN

Time-kinetics studies testing fine morphology of the sperm nuclei upon prolonged in vitro incubation.

SETTING

Male Fertility Laboratory at Bar-Ilan University, Ramat Gan, Israel.

PATIENT(S)

Forty-two males selected at random, who were referred for sperm preselection before ICSI.

MAIN OUTCOME MEASURE(S)

Morphologic integrity of the sperm nuclei, obtained by motile sperm organelle morphology examination.

RESULT(S)

After 2 hours of incubation at 37 degrees C a significant decrease occurred in the morphologic integrity of the sperm nuclei, compared with the initial state (4.7% +/- 2.8% vs. 6.8% +/- 3.5%, t = 3.2, P<or=.01). Correspondingly, a significant increase occurred in the frequency of vacuolated nuclei (80.8% +/- 7.2% vs. 75.0% +/- 7.6%, t = -2.8, P<or=.01). No significant morphologic changes in sperm nuclei were observed upon prolonged incubation at 21 degrees C. After 2 hours of incubation, the incidence of spermatozoa with vacuolated nuclei was significantly higher at 37 degrees C compared with 21 degrees C (56.5% +/- 10.8% vs. 45.5% +/- 10%, t = 6.6, P<or=.01).

CONCLUSION(S)

Prolonged (>or=2 hours) sperm manipulations for assisted reproduction therapy should be performed at 21 degrees C rather than 37 degrees C.

Ultrastructural and Rheological Properties of Bovine Vaginal Fluid and its Relation to Sperm Motility and Fertilization: a Review

The tubular genital organs of the mammalian female reproductive tract provide different luminal microenvironments that can act as an aid or a barrier to gamete transport and the first steps of embryonic development. The mechanism of sperm transport through the genital tract has not been fully established but, first of all, sperm cells encounter and need to overcome mucous-like secretions to reach the site where fertilization occurs. One of these secretions, vaginal fluid, is a complex biological product, which is mainly derived from cervical mucus. In this review, we focus on recent studies that describe the relationships between the ultrastructural and rheological properties of bovine vaginal fluid and sperm motion. In the light of this, we propose bovine vaginal fluid as a morphofunctional model for the study of sperm transport in mammals.

Alterations in semen parameters in men with epilepsy treated with valproate or carbamazepine monotherapy

Men with epilepsy are known to have reduced fertility. Whether this is drug-induced or a result of the epilepsy itself is still under debate. Few studies have been carried out on semen from men with epilepsy. The aim of the present study was first to investigate possible drug-specific effects of long-term treatment with either valproate or carbamazepine on semen quality and testicular size, and secondly to see whether the results in epilepsy patients differed from healthy fertile males. Men with epilepsy, 20-40 years old, having used either valproate (n = 16) or carbamazepine (n = 20) for >2 years, were included. The semen data of healthy fertile men without epilepsy in the same age group (n = 90) were used as controls. The semen was examined according to WHO (1999). No significant differences in semen quality were seen between men receiving either valproate or carbamazepine. However, semen from the valproate-treated, as opposed to the carbamazepine-treated, differed from controls with regard to tail abnormalities. Absolute testicular size was not significantly different between the two treatment groups. However, after correcting for changes in body mass index (BMI), the testicular size/BMI ratio was lower in the valproate-treated patients. The valproate-treated patients gained significantly more weight than the carbamazepine-treated patients after start of current medication. No differences between the patient groups were found in terms of libido/potency or number of pregnancies fathered. When comparing all epilepsy patients with healthy fertile males, there was a significant reduction in the percentage of rapidly progressive motile sperms in the semen from epileptic patients. The semen from men with epilepsy also showed significant differences from the controls regarding neck and head abnormalities of the spermatozoa.

Comprehensive office evaluation in the new millennium

The success of a comprehensive office-based evaluation of male-factor infertility depends on the physician's thorough understanding of risk assessment in the history, identification of pertinent physical examination findings, and correct assessment of laboratory data. Office-based ultrasonographic techniques have already increased the urologist's ability to visualize suspected anatomic abnormalities, and the use of functional tests of sperm has given greater depth to the limited, but essential, prognostic capabilities of the routine semen analysis.

Effects of cryopreservation on penetration ability of human spermatozoa into bovine cervical mucus

Cryopreserved sperm exhibit lower fertilizing capacity in comparison to fresh sperm, partly due to effects of glycerol as the common cryoprotectant medium. Since standard semen analysis is not a good predictive method to assess sperm fertilizing capacity, functional tests like cervical mucus penetration may provide more useful information. A total of 24 semen samples were examined before and after cryopreservation for sperm parameters as well as number and motility of penetrated sperm into bovine cervical mucus (BCM) as an alternative for human cervical mucus. Freezing and thawing procedures have negative effects on sperm penetration into cervical mucus. No significant relation was noticed between sperm motility percentage or its penetration into BCM before and after cryopreservation, which denotes the variability in resistance of sperm to damaging effects of freezing.

Contemporary approach to the male infertility evaluation

Evaluation of infertile couples has revealed that male factor infertility contributes to the problem in up to 50% of cases. Evaluation of the male infertility patient may include endocrine studies, sophisticated semen testing, and select radiographic studies. Reversible and life-threatening causes of male infertility should be identified before proceeding directly to assisted reproductive technology. For cases with irreversible causes, a proper evaluation can identify patients who may be treated with the breakthrough method of intracytoplasmic sperm injection. Many men who were previously thought to be infertile may now initiate their own biologic pregnancies. This article emphasizes the essentials of the contemporary approach to evaluating the male factor in an infertile couple.

Correlation of the bovine cervical mucus penetration test with human sperm characterisitics in 1,406 ejaculates

The bovine cervical mucus penetration test (BCMPT) was performed to determine its usefulness in screening the ability of sperm to successfully penetrate mucus in vitro. Ejaculates were obtained by masturbation from patients attending an infertility clinic. Routine semen analysis was performed using a microcomputerized multiple-exposure photography system. The BCMPT was performed. Overall, the average penetration of the mucus was 38 +/- 0.46 mm. Of the 1,406 ejaculates analyzed, 244 (17%) displayed a negative result (0-20 mm), 291 (21%) a questionable result (21-30 mm), and 871 (62%) a positive result (>30 mm). A highly significant (p < .001) correlation between mucus penetration distance and sperm MD (r = 0.541), MI (r = 0.484), count (r = 0.475), motility (r = 0.448), velocity (r = 0.400) and morphology (r = 0.369) was observed. Overall, the finding of an abnormal semen parameter resulted in a 34 +/- 5% accurate prediction of a negative or questionable BCMPT (<30 mm), while a normal semen parameter resulted in a 90 +/- 4% accurate prediction of a positive BCMPT (>30 mm). Sperm MD showed the strongest positive predictive value (98%), while morphology showed the greatest negative predictive value (50%). Of the 1,406 samples, 25 +/- 2% of the samples with normal semen parameters displayed a negative BCMPT. Conversely, 6 +/- 2% of samples with abnormal parameters showed a positive BCMPT. The BCMPT successfully identifies a significant subpopulation of patients as having an inadequate penetration of mucus with otherwise normal semen characteristics.

Comparison of human cervical mucus and artificial sperm penetration media

The cervical mucus penetration tests aid research and determine the clinical importance of positive sperm antibody tests. Limited availability and variability of human cervical mucus have instigated the search for mucus substitutes for these tests. This study compares sperm migration in cervical mucus with that in artificial media including hyaluronate solution, egg white and albumin Tyrode solution. Results were quantified by measuring the migration distance (the maximum distance of capillary migration from a semen reservoir by spermatozoa after 1 h) and the sperm concentration at half the migration distance. The mean of both measures for cervical mucus and hyaluronate solution were equivalent [4.4 +/- 1.1 (SD) versus 4.3 +/- 1.0 cm and 118 +/- 51 versus 111 +/- 44x10(3)/ml], and higher than in egg white and albumin Tyrode solution. Antisperm antibodies impaired sperm penetration in cervical mucus and hyaluronate solution in a similar manner (r = 0.92). These results suggest that hyaluronate solution sufficiently resembles human cervical mucus in terms of penetrability that it may be used as a substitute for mucus in capillary tube tests of sperm function. The higher penetrability of cervical mucus and hyaluronate solution is probably related to a channelling effect due to their polymeric structure.

Male infertility. Evaluation and nonsurgical therapy

Male infertility is a complicated and often poorly understood pathologic process. The cause of a man's infertility frequently remains unknown even after a thorough evaluation. Many of the currently available medical therapeutic options are empirical and lack documentation of efficacy. New diagnostic tests are emerging that may help define some previously obscure causes of infertility. Only when these abnormalities have been clearly identified will more specific and cost-effective treatment regimens be instituted.