Showing papers on "Sperm motility published in 1989"

Role of glutathione peroxidase in protecting mammalian spermatozoa from loss of motility caused by spontaneous lipid peroxidation.

Abstract: Mouse and human spermatozoa, but not rabbit spermatozoa, have long been known to be sensitive to loss of motility induced by exogenous H2O2. Recent work has shown that loss of sperm motility in these species correlates with the extent of spontaneous lipid peroxidation. In this study, the effect of H2O2 on this reaction in sperm of the three species was investi gated. The rate of spontaneous lipid peroxidation in mouse and human sperm is markedly enhanced in the presence of 1-5 mM H2O2, while the rate in rabbit sperm is unaffected by H2O2. The enhancement of lipid peroxidation, the rate of reaction of H2O2 with the cells, the activity of sperm glutathione peroxidase, and the endogenous glutathione content are highest in mouse sperm, intermediate in human sperm, and very low in rabbit sperm. Inac tivation of glutathione peroxidase occurs in the presence of H2O2 due to complete conver sion of endogenous glutathione to GSSG: No GSH is available as electron donor substrate to the peroxidase. Inactivation of glutathione peroxidase by the inhibitor mercaptosucci nate has the same effect on rate of lipid peroxidation and loss of motility in mouse and human sperm as does H2O2. This implies that H2O2 by itself at 1-5 mM is not intrinsically toxic to the cells. With merceptosuccinate, the endogenous glutathione is present as GSH in mouse and human sperm, indicating that the redox state of intracellular glutathione by itself plays little role in protecting the cell against spontaneous lipid peroxidation. Mouse and human sperm also have high rates of superoxide production. We conclude that the key intermediate in spontaneous lipid peroxidation is lipid hydroperoxide generated by a chain reaction initiated by and utilizing superoxide. Removal of this hydroperoxide by gluta thione peroxidase protects these sperm against peroxidation; inactivation of the peroxidase allows lipid hydroperoxide to increase and so increases the peroxidation rate. Rabbit sperm have low rates of superoxide reaction due to high activity of their superoxide dismutase; lack of endogenous glutathione and low peroxidase activity does not affect their rate or lipid peroxidation. As a result, these sperm are not affected by either H2O2 or mercapto-succinate. These results lead us to postulate a mechanism for spontaneous lipid peroxida tion in mammalian sperm which involves reaction of lipid hydroperoxide and O2 as the rate-determining step.

Lipid peroxidation in human spermatozoa as related to midpiece abnormalities and motility.

Abstract: The formation of malondialdehyde (MDA), a product of lipid peroxidation (LPO), was measured in human spermatozoa from 27 subjects with normal sperm characteristics. Peroxidation of lipids in washed spermatozoa was induced by catalytic amounts of ferrous ions and ascorbate and malondialdehyde determined by thiobarbituric method. MDA formation varied considerably from one sample to another. The studied population showed a strong correlation between lipid peroxidation potential (amount of MDA formed by 10(8) spermatozoa after 1 hour of incubation) and 1) initial motility r = -0.623, P = 0.001; and 2) morphologic abnormalities of the midpiece r = 0.405, P = 0.05. These results suggest that poor motility is linked with membrane fragility and that spermatozoa with midpiece abnormalities probably have membrane and/or cytoplasmic antiperoxidant system defects. Because LPO potential is related to the two most important characteristics of fertility, it seems possible that it has the potential to become a good biochemical index of semen quality.

A consistently successful procedure for in vitro fertilization of golden hamster eggs

Abstract: Complete details are described for the first time of the procedures used in the author's laboratory for obtaining in vitro fertilization (IVF) of golden hamster eggs leading to the first cleavage division. These IVF procedures have been developed during the past 20 years and are very reproducible: IVF of at least 75% of eggs is routinely achieved, and on average 65% of inseminated eggs undergo the first cleavage division in vitro. These results can easily be obtained by inexperienced investigators. The ease and reproducibility of the hamster IVF procedures make them very suitable for studies of sperm:egg interaction and associated events. Studies in the author's laboratory have included analysis of sperm fertilizing ability under chemically defined conditions, the presence of sperm acrosome reaction stimulating factors in the egg investments, maturation of oocytes in vitro, the block to polyspermy, and the contribution of egg aging to fertilization anomalies. In addition, the motility of hamster sperm under chemically defined conditions is used in a routine screening protocol for detecting contaminants in the culture milieu. Golden hamster gametes offer several distinct advantages for IVF studies, including the large size of the sperm acrosome, the persistence of the very large sperm tail in the ooplasm for many hours following fertilization, and the translucence of the ooplasm, which facilitates observation of the sperm tail and pronuclei. The female golden hamster exhibits a regular 4 day estrous cycle, with distinctive indications of estrus and proestrus phases. Because of the advantages of using the golden hamster, the procedures described in this report may be useful to other investigators wishing to conduct research using IVF. Essentially the same IVF procedures can be used with monkey and bovine gametes.

Factors regulating mammalian sperm migration through the female reproductive tract and oocyte vestments.

Abstract: Mechanisms of mammalian sperm migration through the female reproductive tract and ovum vestments are described. The perspective is biophysical as well as biochemical and morphological, and the focus is upon the role of sperm motility in these processes. Sperm forward progression is characterized as an interactive process between the the cell and its environment, and the mediation of flagellar bend propagation by the physical properties of its surroundings is described. These properties, together with flagellar beat kinematics, sperm morphology, and surface properties, determine the magnitude of the forces generated by sperm and their consequent rate of progression. Sperm interactions with the cervical mucus, the cumulus oophorus, and the zona pellucida are described. The poorly understood affinity of the sperm surface for the macromolecules of the mucus, cumulus, and zona is stressed, as is the viscoelastic structural mechanical resistance of these biopolymers to sperm motion. The kinematics and consequences of hyperactivated sperm motion are presented, with emphasis on objective characterization of such motion (as a biomarker), along with analysis of the mechanical advantage that such motion may confer on spermatozoa during egg-vestment interaction.

Relationship between calcium, cyclic AMP, ATP, and intracellular pH and the capacity of hamster spermatozoa to express hyperactivated motility.

Abstract: Capacitation of hamster caudal spermatozoa at a density of 1 x 10(6)/ml is associated with a progressive rise in cAMP levels that precedes the onset of hyperactivated motility. This increase is not expressed by caput spermatozoa incubated under identical conditions. Both the incidence of hyperactivation and the rise in cAMP levels are severely attenuated in the absence of exogenous calcium. Neither factor is restored to control levels by the addition of the phosphodiesterase inhibitor IBMX, although in the presence of exogenous calcium, this reagent increased cAMP levels, stimulated percentage motility and advanced the appearance of hyperactivation. Treatment of spermatozoa at a density of 1 x 10(6)/ml with the calmodulin antagonist, calmidazolium (CZ), caused severe disruption of sperm motility and abolished hyperactivation, while causing only a slight reduction in cAMP content. Addition of IBMX in the presence of CZ elevated cAMP content to levels higher than normally observed during capacitation but did not restore either coordinated or hyperactivated motility. To determine both the mechanisms responsible for this elevation of cAMP content and the changes that occur during epididymal maturation to facilitate the expression of this increase, the free cytosolic calcium concentration, ATP levels, and intracellular pH of caput and caudal cells were compared. The calcium content of caudal spermatozoa rose significantly at a time when cAMP levels were increasing, while ATP content and intracellular pH fell. However, the inability of caput spermatozoa to express a rise in cAMP content was not due to deficiencies in any of these factors. These results indicate a positive role for the cAMP rise in the expression of hyperactivated motility and that the fundamental control mechanism governing both these events may be the influx of calcium that accompanies capacitation in this species.

Regulation of mammalian sperm motility.

Abstract: The physiological regulation of sperm motility has become more amendable to investigation since the demonstration that cAMP and calcium play a role in modulating the functioning of the flagellar axoneme. Although the external triggering mechanisms that initiate motility and capacitation are still unknown, evidence supports a modification of the calcium balance by gated Ca2+ channels, accompanied by shifts in the internal pH. Ca2+ and pH may in turn act indirectly through cAMP and cAMP-dependent kinase (kinase(a] to control the phosphorylation state of functional proteins in the flagellar axoneme. The role of calcium is of central importance, but it is clear that several separate Ca2+-dependent mechanisms are involved. Ca2+ controls the curvature of the sperm flagellum and, so, can change the motility of the sperm from progressive swimming to tumbling. Under the appropriate conditions, calcium appears to have the capacity to deactivate motility by activating phosphodiesterase and phosphatase. The deactivating effect of Ca2+ may be offset under some circumstances by coactivation of adenyl cyclase, so phosphorylation of the axoneme and the motility are maintained. The specific factors determining the predominant calcium effect are not yet known, but internal pH of the sperm may play a major role.

Recovery of sperm production after chemotherapy for osteosarcoma.

Abstract: Because treatment with surgery and combination chemotherapy produces a high cure rate in young men with osteosarcoma, their subsequent reproductive function is an important concern. Semen analyses of osteosarcoma patients, therefore, were performed before, during, and after treatment with the PADIC regimen consisting of cisplatin, Adriamycin (doxorubicin), and dacarbazine or, in some cases, the PADIC regimen plus additional drugs. Results showed that semen volume was not affected and that sperm motility was reduced only during treatment. Although nearly all patients were rendered azoospermic during treatment, sperm production resumed in 30 of 32 patients examined at least 2 years after treatment. Analysis with correction for censored data indicates that, in 78% of treated men, sperm counts will return to more than 10 million/ml. The percentage of men whose sperm counts recovered to normal was lower for those receiving cisplatin dosages greater than or equal to 600 mg/m2; no trends were observed with Adriamycin and dacarbazine dosages. The inclusion of additional drugs such as methotrexate, bleomycin, dactinomycin, or cyclophosphamide (less than 4 g/m2) did not significantly affect the recovery of spermatogenesis. We conclude that the risk of long-term infertility from treatment with the PADIC regimen is low.

The hemizona assay (HZA): a predictor of human sperm fertilizing potential in in vitro fertilization (IVF) treatment.

Abstract: The hemizona assay (HZA) was developed to assess human sperm fertilizing potential. This blinded study investigated the relationship between sperm binding to the hemizona and in vitro fertilization (IVF) success (36 patients). Nonliving human oocytes were recovered from excised ovaries and stored. Each zona pellucida was cut into equal hemispheres by micromanipulation. For the HZA, one droplet exposed a hemizona to abnormal spermatozoa, while the control droplet contained the matching hemizona and spermatozoa from normal semen. After 4 hr, the number of tightly bound spermatozoa was counted. Binding to the hemizona was significantly higher for those having IVF success (mean of 36.1±7, versus 10.4±4 from the failure group;P<0.05). Fewer sperm from the failure group had a strictly normal morphology (3,2 versus 12.7%;P<0.05, Kruger method). Tight zona binding was significantly correlated with the percentage motile sperm, percentage normal morphology, and seminal sperm concentration. These results enhanced our confidence that the HZA is diagnostic for identification of patients at high risk of failing to achieve fertilization in vitro.

Micromanipulation of sperm by a laser generated optical trap - eScholarship

Abstract: The force generated by the radiation pressure of a low power laser beam induces an optical trap which may be used to manipulate sperm. We studied the effect of the optical trap on sperm motility. A Nd:YAG laser beam was coupled to a conventional microscope and focused into the viewing plane by the objective lens. Sperm were caught in the trap and manipulated by a joy stick controlled motorized stage. After different exposure periods, the velocity and patterns were analysed by a computerized image processor. There were minor changes in sperm velocity when exposed to the trap for 30 seconds or less. A gradual decrease in the mean linear velocity was observed after 45 seconds of exposure. This optical micromanipulator may also be useful for studying the force generated by a single spermatozoa and evaluating the influence of drugs on motility.

Rise of internal Ca2+ accompanies the initiation of trout sperm motility

Abstract: The initiation of motility of trout spermatozoa is inhibited by the presence of millimolar concentrations of external K+, but external Ca2+ might also be implicated in this control as it has been shown to antagonize the K+ inhibition of motility [S.M. Baynes et al.: J. Fish. Biol., 19:259–267, 1981]. The present work aimed to investigate internal Ca2+ levels during the motility phase of trout spermatozoa. Internal Ca2+ concentrations were monitored by the fluorescent quinoline Ca2+-indicator, “Quin-2” [R. Y. Tsien: Nature 290:527–529, 1981]. Trout spermatozoa were loaded with Quin-/ under conditions that gave efficient intracellular hydrolysis of Quin-2 and that did not impair the ability of loaded spermatozoa to initiate movement. The beat frequencies, cell velocities, and flagellar asymmetries of sperm movement were not significantly modified by the presence of the internal dye. Upon initiation of flagellar movement, an increase of the internal Quin-2 fluorescence was observed that reflected a sixfold increase of the free Ca2+ concentration. The free Ca2+ remained elevated after the cessation of movement. The variation of fluorescence was completed within 40 seconds, whereas the initiation of motility was nearly instantaneous, and the total duration of flageliar beating lasted for about 80–100 seconds (measurements at 11°C). The increase in the internal free Ca2+ concentration is completed after the initiation of flagellar beating but its occurrence correlates with that of sperm movement. Fluorescence increase was not observed in the presence of 40 mM K+, a condition in which spermatozoa did not initiate flagellar beating. In the presence of the Ca2+ channel blocker desmethoxyverapamil, neither sperm motility nor fluorescence increases were observed, which suggested that the increase of internal free Ca2+ was produced by a flux of external Ca2+ into the cell rather than by a mobilization of internal Ca2+ stores.

Calcium requirement and increased association with bovine sperm during capacitation by heparin.

Abstract: The requirement for external Ca+2 during capacitation of ejaculated bovine sperm with heparin and changes in sperm-associated 45Ca+2 during capacitation were investigated in vitro. Sperm capacitation was evaluated by ability to undergo an acrosome reaction (AR) upon exposure to lysophosphatidylcholine. The percentage of sperm which were capacitated during a 4 h incubation with heparin increased exponentially with increased exposure time to 2 mM Ca+2. When sperm were incubated with or without heparin in the presence of 45CaCl2, there was no difference in the amount of 45Ca+2 associated with sperm initially or at 1 h of incubation. Incubation with heparin resulted in a greater amount of sperm-associated 45Ca+2 at 2, 3, and 4 h as compared to sperm incubated without heparin. The amount of 45Ca+2 associated with sperm during capacitation was unaffected by washing with 2 mM EGTA-5 mM LaCl3. Glucose (5 mM) inhibited the effects of heparin on sperm-associated 45Ca+2 and on capacitation. The inhibitory effects of glucose could be overridden by 8-bromo-cAMP. The results suggest that the requirement for external Ca+2 during capacitation with heparin may be related to an increased association of external Ca+2 with sperm.

Quality control during the conventional analysis of semen, an essential exercise.

Abstract: Intra- and inter-technician variability in assessing sperm motility by the methods recently advocated by the World Health Organization (WHO) were studied. The intra- and inter-technician variability in estimating sperm concentration and the intra-technician variability in assessing sperm morphology were also examined. Intra-technician variability in assessing sperm motility appeared to be related to the natural ability and/or training of the observer. Although in general the intra-technician variability was low, there were marked and clinically significant differences between observers when assessing the same semen sample. There was no significant difference between observers in the assessment of sperm concentration, and intra-technician variability was low. When assessing sperm morphology, the intra-technician variability was potentially large (above a level of 20% morphologically ideal spermatozoa). Technicians should be recruited who have natural ability as observers. Quality control appears to be an essential exercise for any center that plans to relate semen parameters to fertility outcome.

Effect of Sperm Motility on Human In Vitro Fertilization

Abstract: Several sperm motility parameters in semen prepared by the swim-up technique were compared with IVF rates in 84 patients. The patients were either on clomiphene + human menopausal gonadotrophin or follicle stimulating hormone + human menopausal gonadotrophin stimulation regimens. Motility ratings were assessed both manually according to World Health Organization guidelines as well as computer-automated semen analysis (Cellsoft, Cryoresources, USA). Motility ratings of greater than or equal to 2 yielded significantly higher fertilization rates (78-82%) than ratings below 2 (20-23%) (p less than 0.001) for patients on both regimens. Velocity (41, 55, 78 microns/sec) and mean amplitude of lateral head displacement (1.96, 3.29, 4.91 microns) correlated significantly with and between manual ratings of 1, 2, and 3, respectively (r = 0.83; p less than 0.01). No significant differences were observed in linearity and beat/cross frequency between the manual ratings, although beat/cross frequencies tended to reduce linearly with increases in intensity of motility. The velocity of sperm motility has a significant effect on fertilization rates, and cut-off points of greater than or equal to 2 or greater than or equal to 50 microns/sec predict the actual potential and likely success of in vitro fertilization. These criteria on the swim-up semen should be used in the selection of patients admitted to IVF programs, and they justify the necessity of research investigations to improve motility in those patients with sluggish motility.

Pregnancy after vasovasostomy for vasectomy reversal: a study of factors affecting long-term return of fertility in 282 patients followed for 10 years

Abstract: The aim of this study was to determine the eventual fertility of those patients following vasectomy reversal who have no pressure-induced secondary epididymal blockage. These patients underwent simple vasovasostomy because at the time of the reversal surgery there were sperm present in large numbers in the vas fluid. It was possible to obtain long-term follow-up on 326 early patients who underwent vasectomy reversal 8-10 years ago. Two hundred and eighty-two of those patients had sperm in the vas fluid. These patients were studied for pregnancy rate and post-operative semen parameters in relation to presence or absence of sperm in the vas fluid at the time of vasectomy reversal, duration of time since vasectomy, pre-operative serum antisperm antibody titers, the influence of varicocoele and quantitative evaluation of testicular biopsy. All of the 44 patients with no sperm in the vas fluid remained azoospermic following vasovasostomy. Of the 282 patients with sperm in the vas fluid, 228 (81%) eventually impregnated their wives. Twenty-four patients with sperm in the vas fluid (9%) were azoospermic and did not impregnate their wives. Of the 258 patients who had sperm patency, the pregnancy rate was 88%. The number of mature spermatids per tubule in the testis correlated closely with the post-operative sperm count in patent cases. Quantitative evaluation of the testicular biopsy revealed normal spermatogenesis, even in patients with azoospermia or severe oligospermia post-operatively. Technical failures were due to blockage either at the vasovasostomy site, or epididymal blockage unrecognized at the time of vasovasostomy.2+perm count had a minimal impact on the

The effect of tumor necrosis factor on human sperm motility in vitro.

Abstract: Tumor necrosis factor (TNF alpha) is present in elevated levels in peritoneal fluid from infertile women with endometriosis. The effect of TNF alpha on human sperm motility in vitro was evaluated utilizing peritoneal fluid from infertile women with minimal endometriosis containing 0, 100, 400, or 800 U of TNF alpha/ml as well as similar concentrations of recombinant human TNF alpha. No reduction in progressive and total motility was found at recombinant TNF alpha concentrations of 100 U ml. However, 500 and 1000 U of recombinant TNF alpha/ml caused a significant reduction in progressive and total sperm motility after 4 and 21 hours of incubation when compared with controls. Similarly, peritoneal fluid containing 100 U of TNF alpha/ml did not significantly reduce progressive and total sperm motility after either 4 or 21 hours of incubation; but peritoneal fluid containing 400 U of TNF alpha/ml reduced progressive sperm motility after 4 and 21 hours and total sperm motility after 21 hours of incubation. Peritoneal fluid with a TNF alpha concentration of 800 U/ml caused a significant reduction in both progressive and total sperm motility after 4 and 21 hours when compared with controls of TNF alpha-negative peritoneal fluid. The addition of polyclonal rabbit anti-TNF alpha antibody or 30-min heat inactivation at 56 C of TNF alpha-positive peritoneal fluid reversed the inhibitory effect on sperm motility. The ability of TNF alpha to cause a significant reduction of sperm motility in vitro suggests that this may be a mechanism for the infertility observed in women with minimal endometriosis.

Semen quality in workers exposed to 2-ethoxyethanol.

Abstract: To evaluate whether long term exposure to 2-ethoxyethanol (2EE) may affect semen quality, a cross sectional study was conducted among men exposed to 2EE used as a binder slurry in a metal castings process. Full shift breathing zone exposures to 2EE ranged from non-detectable to 24 ppm (geometric mean 6.6 ppm). Because of the potential for substantial absorption of 2EE through skin exposure, urine measurements of the metabolite of 2EE, 2-ethoxyacetic acid (2EAA) were conducted, showing levels of 2EAA ranging from non-detectable to 163 mg 2EAA/g creatinine. Only 37 exposed men (50% participation) and 39 non-exposed comparison (26% participation) from elsewhere in the plant provided a sperm sample. A questionnaire to determine personal habits, and medical and work histories, and a physical examination of the urogenital tract were also administered. The average sperm count per ejaculate among the workers exposed to 2EE was significantly lower than that of the unexposed group (113 v 154 million sperm per ejaculate respectively; p = 0.05) after consideration of abstinence, sample age, subjects' age, tobacco, alcohol and caffeine use, urogenital disorders, fever, and other illnesses. The mean sperm concentrations of the exposed and unexposed groups did not significantly differ from each other (44 and 53 million/ml respectively). No effect of exposure to 2EE on semen volume, sperm viability, motility, velocity, and normal morphology or testicular volume was detected, although some differences in the proportion of abnormal sperm shapes were observed. These data suggest that there may be an effect of 2EE on sperm count among these workers, although the possibility that other factors may be affecting the semen quality in both exposed and unexposed men in this population or that the results reflect bias introduced by the low participation rates cannot be excluded.

Synchronous assay for human sperm capacitation and the acrosome reaction

Abstract: A synchronous acrosome reaction system was established for human spermatozoa. Seminal plasma is removed from the spermatozoa by centrifugation and the washed spermatozoa are capacitated in a modified BWW medium (without exogenous substrates) containing 35 mg/ml human serum albumin for 3 h at 37 C. Subsequently, 10 microM ionophore A23187 (final concentration) is added, the mixture incubated for 15 min at 37 C and the percent acrosome reaction determined by a modified triple stain technique (trypan blue stain omitted). Since no significant decrease in sperm motility occurs during incubation or after ionophore treatment, a vital stain does not need to be employed, allowing the use of any acrosome detection technique. The average percentage of acrosome-rejected spermatozoa after ionophore treatment (40 +/- 10%) was about 2- to 3-fold higher than that seen without ionophore treatment. Ionophore treatment for 15 min failed to stimulate the acrosome reaction in spermatozoa incubated for less than 3 h. Additionally, the presence of substrates in the BWW medium, higher sperm numbers, increased ionophore concentrations or longer incubation periods did not enhance the induction of the acrosome reaction. Ionomycin, a more specific calcium ionophore than A23187, produced essentially the same results as A23187 but tended to decrease sperm motility. This synchronous acrosome reaction system for human spermatozoa is relatively simple and can be used to study the effect of modulators on capacitation and/or the acrosome reaction.

Germ cell function and hormonal status in patients with testicular cancer.

Abstract: Sperm counts, serum gonadotropins, and androgen levels were investigated in 39 seminoma patients and 58 patients with a nonseminomatous germ cell tumor of the testis after unilateral orchiectomy. In 58% of the patients, the total sperm count was below the lower reference value (80 million). A multiregression analysis demonstrated a correlation between a decreased total sperm count and the following three explanatory variables: (1) an elevated serum alpha-fetoprotein (AFP), (2) a history of chryptorchidism, or (3) a seminomatous tumor. In 42% of the patients, the sperm concentration and the sperm motility met criteria considered sufficient for cryopreservation. Serum follicle-stimulating hormone (FSH) was elevated in 33% of the patients. Androgens (serum testosterone [T] or urine 17-oxy-steroids [17-OS]) were subnormal in 5% of the patients, whereas serum luteinizing hormone (LH) was elevated in 14% of the patients without human chorionic gonadotropin beta-subunit (beta-HCG) in serum.

Intracellular pH regulates bovine sperm motility and protein phosphorylation.

Abstract: Bovine sperm in neat caudal epididymal fluid become motile in response to either pH elevation or dilution of the fluid. Buffers containing permeant weak acids at physiologic concentrations are able to mimic these effects of caudal fluid. These observations lead to the hypothesis that a pH-dependent epididymal fluid quiescence factor regulates bovine sperm motility by modulating sperm intracellular pH (pHi). Here we report that sperm pHi, measured with the fluorescent pH probe carboxyfluorescein, increases by approximately 0.4 units in response to either of these motility-initiating manipulations. At least 26 discrete phosphoprotein bands are distinguishable by sodium dodecylsulfate-polyacrylamide gel electrophoresis after incubation of intact caudal sperm with 32PO4. A prominent phosphoprotein, with Mr approximately 255,000 (pp255) and a relatively high specific radioactivity, is reversibly dephosphorylated in response to elevations in pHi that initiate sperm motility. Unlike most of the sperm phosphoproteins, the extraction of pp255 requires reducing agents. This phosphoprotein cosediments with the sperm heads but not the tail, midpiece, soluble, or plasma membrane fractions. No other pHi-dependent phosphorylation changes are apparent in gels of whole sperm extracts. However, subcellular fractionation allows the detection of increased phosphorylation of two plasma membrane phosphoproteins (Mr approximately 105,000 and 97,000) and decreased phosphorylation of another plasma membrane phosphoprotein (Mr approximately 120,000) in response to increasing pHi. This is the first report describing changes in endogenous phosphoproteins from intact motile and nonmotile bovine sperm that are regulated by pHi.

Human sperm mitochondrial function related to motility: a flow and image cytometric assessment

Abstract: Current evaluation of male fertility, routinely estimated by sperm count, motility, and morphology, provides only crude information about the fertility state of individuals. Both flow and image cytometry were applied to mitochondrial activity and sperm motility respectively. Sperm samples from fertile donors were concomitantly measured for Rhodamine 123 (Rh123) uptake (an estimation of mitochondrial activity), percentage of dead cells, and motility characteristics, such as percentage of motility, curvilinear velocity, and amplitude of lateral head displacement. These measurements were done under experimental conditions known to modulate sperm motility (temperature and time course survival in a capacitating medium). Bimodal distributions were found for Rh123 uptake. Flow cytometry-derived parameters were essentially time-dependent whereas motility characteristics were primarily temperature-dependent. Correlations were found between various flow cytometry-derived parameters and motility characteristics. Most of the correlations were obtained after a 24 h incubation in a capacitating medium. The most significant correlation in every experimental condition concerned the percentage of motile spermatozoa and the Rh123 uptakes. The drop in motility observed after a 24 h incubation was paralleled by a markedly lower drop in mitochondrial activity. The data suggest that these two complementary techniques represent an improvement in basic and/or clinical assessment of the functional spermatozoa status.

Improvement of survival and fertilizing capacity of human spermatozoa in an IVF programme by selection on discontinuous Percoll gradients

Abstract: Two techniques for the separation of spermatozoa were compared: swim-up migration (SUM) and centrifugation on a discontinuous Percoll gradient (CPG). Their respective effects on sperm motility were analysed by computer-assisted videomicrography in either normal or asthenozoospermic groups. In both groups, there was no difference in any of the motion parameters between the two treatments after 1-h incubation. However, a clear difference was observed after 24 h when excellent motility was retained only in the CPG-treated group. A total of 350 ejaculates were produced by the husbands of women undergoing oocyte retrieval in an IVF programme. Spermatozoa were treated by CPG when the infertility was due to poor quality spermatozoa (n = 91), when there was a known previous history of semen infection (n = 73) or when frozen semen, originating from a donor, was used (n = 36). In all other cases (n = 150), spermatozoa were treated by SUM. The cleavage rates obtained were 32.2, 70.1, 60.9 and 68.6% respectively in the four categories. The clinical pregnancy rates per oocyte retrieval were 19.8, 31.5, 22.2 and 18.0% respectively. Forty-eight births occurred in the CPG group: 28 boys and 20 girls, all normal. We conclude that CPG is useful, both in cases of poor semen quality and in tubal infertility, in which the clinical pregnancy rate increased significantly from 18.0 to 31.5%.

Relaxin in the male.

Abstract: Relaxin, a hormone usually associated with pregnancy, has been found in the semen plasma of many species. The prostate gland appears to be a source of relaxin. Relaxin stimulates sperm motility from suboptimal samples and increases sperm penetration into oocytes. Thus, relaxin may be an effective therapeutic agent in male infertility.