Showing papers on "Sperm motility published in 1996"

Effects of an Igf1 gene null mutation on mouse reproduction.

Abstract: Both sexes of adult mice homozygous for a targeted mutation of the Igf1 gene, encoding insulin-like growth factor 1, are infertile dwarfs (approximately 30% of normal size). The testes are reduced in size less than expected from the degree of dwarfism but sustain spermatogenesis only at 18% of the normal level. The epididymides are overall nearly allometric to the reduced body weight, but the distal regions of the duct, vas deferens, seminal vesicles, and prostate are vestigial. Despite the mutational impact on the epididymis, capacitated sperm are able to fertilize wild type eggs in vitro. It is hypothesized that the infertility of male mutants is caused by failure of androgenization resulting in absence of mating behavior, due to drastically reduced levels of serum testosterone (18% of normal). This hormonal deficiency was correlated with an ultrastructural analysis of mutant Leydig cells revealing a significant developmental delay, while assays in organ culture showed that the basal and LH-stimulated production of testosterone by testicular parenchyma is reduced in comparison with wild type controls. The female mutants fail to ovulate even after administration of gonadotropins, which is apparently the primary cause of their infertility, and possess an infantile uterus that exhibits a dramatic hypoplasia especially in the myometrium. The phenotypic manifestations of the mutation were correlated with the localization of transcripts for insulin-like growth factor I and its cognate receptor in wild type reproductive tissues by in situ hybridization.

Lipid Peroxidation and Human Sperm Motility: Protective Role of Vitamin E

Abstract: Asthenospermia is the main factor of male infertility among patients consulting the Asir Infertility Center in Abha, Saudi Arabia. Lipid peroxidation occurring in both the seminal plasma and spermatozoa was estimated by malondialdehyde (MDA) concentration. Spermatozoal MDA concentration was higher in men with decreased sperm motility. The MDA concentration in the seminal plasma exhibited no relationship with sperm concentration, sperm motility, the number of immotile spermatozoa, or even the absence of spermatozoa. The MDA concentration in sperm pellet suspensions of asthenospermic and oligoasthenospermic patients was almost twice that of the normospermic males. The MDA concentration in the sperm pellet suspension from normospermic or oligospermic patients was about 10% that in the seminal plasma. However, the MDA concentration in the sperm pellet suspension of asthenospermic or oligoasthenospermic patients was about 15% that in the seminal plasma. Treatment of asthenospermic patients with oral Vitamin E significantly decreased the MDA concentration in spermatozoa and improved sperm motility. Eleven out of the 52 treated patients (21%) impregnated their spouses; nine of the spouses successfully ended with normal term deliveries, whereas the other two aborted in the first trimester. No pregnancies were reported in the spouses of the placebo-treated patients.

Evidence of deteriorating semen quality in the United Kingdom: birth cohort study in 577 men in Scotland over 11 years

Abstract: Objective: To determine whether the quality of semen has changed in a group of over 500 Scottish men born between 1951 and 1973. Design: Retrospective review of data on semen quality collected in a single laboratory over 11 years and according to World Health Organisation guidelines. Setting: Programme of gamete biology research funded by Medical Research Council. Subjects: 577 volunteer semen donors. Of these, 171 were born before 1959, 120 were born in 1960-4, 171 in 1965-9, and 115 in 1970-4. Main outcome measures: Conventional criteria of semen quality including semen volume (ml), sperm concentration (106/ml), overall motility (% motile), total number of sperm in the ejaculate (106), and total number of motile sperm in the ejaculate (106). Results: When the four birth cohort groups were compared a later year of birth was associated with a lower sperm concentration, a lower total number of sperm in the ejaculate, and a lower number of motile sperm in the ejaculate. The median sperm concentration fell from 98x106/ml among donors born before 1959 to 78x106/ml among donors born after 1970 (P=0.002). The total number of sperm in the ejaculate fell from 301x106 to 214x106 (P=0.0005), and the total number of motile sperm in the ejaculate fell from 169.7x106 to 129.0x106 (P=0.0065). Conclusion: This study provides direct evidence that semen quality is deteriorating, with a later year of birth being significantly associated with a reduced number of sperm in adult life. Key messages Key messages When men born in the 1970s were compared with men born in the 1950s, the total number of motile sperm in the ejaculate was reduced by almost 25% These data confirm previously published data from other countries that semen quality is changing, declining by about 2.1% per year Research is urgently required to examine the function as well as the number of sperm and to assess whether these changes are affecting human health and male fertility

Development of an image analysis system to monitor the retention of residual cytoplasm by human spermatozoa : Correlation with biochemical markers of the cytoplasmic space, oxidative stress, and sperm function

Abstract: A method has been developed for quantifying the residual cytoplasm present in the midpiece of human spermatozoa, based upon the imaging of NADH oxidoreductase activity. This procedure used NADH and nitroblue tetrazolium as electron donor and acceptor, respectively, and resulted in the discrete staining of the entire midpiece area, including the residual cytoplasm. Image analysis techniques were then used to generate binary images of the midpiece, from which objective measurements of this cellular domain could be undertaken. Such data were found to be highly correlated with biochemical markers of the cytoplasmic space, such as creatine kinase (CK) and glucose-6-phosphate dehydrogenase (G-6-PDH), in sperm populations depleted of detectable leukocyte contamination. Morphometric analysis of the sperm midpiece was also found to reflect semen quality in that it predicted the proportion of the ejaculate that would be recovered from the high-density region of Percoll gradients and was negatively correlated with the movement and morphology of the spermatozoa in semen. Variation in the retention of excess residual cytoplasm was also associated with differences in the functional competence of washed sperm preparations, both within and between ejaculates. Thus, within-ejaculate comparisons of high- and low-density sperm subpopulations revealed a relative disruption of sperm function in the low-density fraction. This disruption was associated with the presence of excess residual cytoplasm in the midpiece, high concentrations of cytoplasmic enzymes, and the enhanced-generation reactive oxygen species (ROS). Functional differences between individual high-density Percoll preparations were also negatively correlated with the area of the midpiece and the corresponding capacity of the spermatozoa to generate ROS. These findings suggest that one of the factors involved in the etiology of defective sperm function is the incomplete extrusion of germ cell cytoplasm during spermiogenesis as a consequence of which the spermatozoa experience a loss of function associated with the induction of oxidative stress.

Nitric oxide synthase and nitrite production in human spermatozoa: evidence that endogenous nitric oxide is beneficial to sperm motility

Abstract: The aim of this study was to investigate the presence of nitric oxide synthase (NOS) and the production of nitric oxide (NO) by human spermatozoa. Immunoreactivity was examined using a polyclonal antibody raised against porcine cerebellar nitric oxide synthase and monoclonal endothelial (elMOS) and brain (bNOS) antibodies. Using each antibody, NOS was observed localized in the head and midpiece regions of the spermatozoon. Immunofluorescence observed for eNOS and bNOS was more intense in normozoosperm ic samples. Sperm motility was assessed by computer-assi sted semen analysis (CASA) in the presence and absence of N G-nitro-L-arginine methyl ester (L-NAME; 10~5M), an NO synthesis inhibitor or tumour necrosis factor (TNF)-a (20 lU/ml), a superoxide inducer. In the presence of L-NAME, percentage progressive motility, average path velocity (VAP), straight line velocity (VSL) and curvilinear velocity (VCL) were significantly reduced after 30 min. Sperm viability was not decreased by TNFoc or L-NAME. The accumulation of nitrite (the stable end-product of the NOS/NO pathway) by spermatozoa was measured using the Griess reaction. After 8 h, nitrite concentrations were lower in asthenozoospermic compared to normozoosperm ic samples. In the presence of TNFcc, nitrite accumulation was significantly reduced in normozoosperm ic samples. We conclude that NOS is present in human spermatozoa and that eNOS and bNOS are abundant in normozoospermic samples. Nitric oxide (at endogenous concentrations) appears to be necessary for adequate sperm motility.

Role of free L-carnitine and acetyl-L-carnitine in post-gonadal maturation of mammalian spermatozoa

Abstract: Spermatozoa are produced in the testis and undergo post-gonadal modifications in the epididymis to acquire fertilizing ability. In epididymal plasma, high-molecular-weight proteins and such small molecules as free-L carnitine convert the gametes into "competent' and functional cells. This review summarizes the knowledge pertaining to L-carnitine and the significance of free L-carnitine uptake into the mature spermatozoa of mammals. We provide an overview of the function of free L-carnitine and carnitine esters in the metabolism of eukaryotic cells and review the role of the specific carnitine acyltransferases in mitochondrial transport of fatty acids and in modulating acyl-coenzyme A (CoA) pools in cellular organelles. In mammals, including man, free L-carnitine is taken from blood plasma and concentrated in the epididymal lumen. This epididymal secretion is beneficial for spermatozoa and is not merely an excretory waste. The uptake of free L-carnitine into the spermatozoa and its metabolic outcome are discussed first in in-vivo and then in in-vitro situations. Free L-carnitine goes through the sperm plasma membrane by passive diffusion. Free L-carnitine is acetylated in mature spermatozoa only. The excess acetyl-CoA from the mitochondria is probably stored as acetyl-L-carnitine and modulates the reserves of free CoA essential to the function of the tricarboxylic acid cycle. These properties of L-carnitine of buffering CoA in the mitochondrial matrix are known in somatic cells but are accentuated in this study of the male germinal cells. In the future, a precise measurement of the in-vivo and in-vitro concentrations of free CoA and acetyl-CoA in the cellular compartments of immature and mature spermatozoa might complete these data. The relationship between the endogenous pools of free and acetylated L-carnitine and the percentage of progressive sperm motility indicates a more important metabolic function related to flagellar movement. In conclusion, the potential to initiate sperm motility, which takes place in the epididymis, is probably independent of the carnitine system, while the energy properties of acetyl-L-carnitine can only be relevant in situations of "energy crisis'. The uptake of "cytoplasmic' free L-carnitine in mature spermatozoa must be a protective form of mitochondrial metabolism, useful to the survival of this isolated cell.

Sperm motility development in the epididymis is associated with decreased glycogen synthase kinase-3 and protein phosphatase 1 activity.

Abstract: Immotile bovine caput epididymal sperm contain levels of protein phosphatase activity twofold higher than do mature motile caudal sperm. Comparison of the inhibition profiles of endogenous phosphatase activities detected by okadaic acid (OA) and calyculin A (CA) revealed a pattern consistent with the predominance of a type 1 protein phosphatase (PP1). Immunoblot analysis identified PP1 gamma 2 (the testis-specific isoform of PP1) as the only PP1 isoform in sperm and showed little protein phosphatase 2A (PP2A). In addition, of the known PP1 inhibitors, i.e., DARPP-32, inhibitor 1 (I1), and inhibitor 2 (I2), only I2-like activity was detected in sperm. Inhibition of PP1 by the heat-stable I2-like activity purified from sperm could be reversed with purified glycogen synthase kinase-3 (GSK-3). Furthermore, sperm extracts contain an inactive complex of PP1 and I2 (termed PP1I) that could also be activated by purified GSK-3. The presence of GSK-3 in sperm was demonstrated by activation of purified PP1I, and quantitation revealed that immotile caput sperm contained sixfold higher GSK-3 activity than motile caudal sperm. Immunoblot analysis confirmed the expression of GSK-3 in sperm and revealed the occurrence of both the alpha and beta isoforms. Our findings suggest that the higher PP1 activity measured in immotile sperm, presumably due to higher GSK-3 activity, is responsible for holding motility in check. This conclusion was supported by the observation that the phosphatase inhibitors OA and CA, at micromolar and nanomolar levels, respectively, were able to induce motility in completely immotile bovine caput epididymal sperm and to stimulate the kinetic activity of mature caudal sperm. The intrasperm levels of cAMP, pH, and calcium were unaltered by treatment with these inhibitors. The results suggest a biochemical basis for the development and regulation of sperm motility and a possible physiological role for the PP1/I2/GSK-3 system.

Semen quality of men employed at a lead smelter

Abstract: OBJECTIVE: To evaluate the effects of recent and long term occupational lead exposure on indicators of male reproductive health. METHODS: In a cross sectional study of male employees of a lead smelter (n = 2469), blood samples were obtained from 152 workers including 119 who also provided semen samples. Semen analysis and serum concentrations of testosterone, follicle stimulating hormone, and luteinising hormone were used as indicators of reproductive health. Semen and hormone variables were examined in relation to measures of current and long term body lead burden estimated from current blood lead concentrations and historical blood lead monitoring data. RESULTS: For current blood lead concentration groups of 40 micrograms/dl, the geometric mean sperm concentrations were, respectively, 79.1, 56.5, 62.7, and 44.4 million cells/ml and geometric mean total sperm counts were 186, 153, 137, and 89 million cells (P for trend 0.04). Compared with workers with blood lead concentrations less than 15 micrograms/dl, workers with current blood lead concentrations of 40 micrograms/dl or more had an increased risk of below normal sperm concentration (odds ratio (OR) 8.2, 95% confidence interval (95% CI) 1.2-57.9) and total sperm count (OR 2.6, 95% CI 0.4-15.7), based on World Health Organisation standards. Independent of current lead exposure, sperm concentration, total sperm count, and total motile sperm count were inversely related to measures of long term lead exposure. No association was found between lead exposure and measures of sperm motility, sperm morphology, or serum concentrations of reproductive hormones. CONCLUSIONS: Blood lead concentrations below the currently accepted worker protection criteria seem to adversely affect spermatogenesis.

Effect of Sperm Lipid Peroxidation on Fertilization

Abstract: This study was aimed at determining, with homologous mouse gametes, whether a level of membrane lipid peroxidation insufficient to affect sperm motility parameters can alter sperm fertilizing potential. The addition of ferrous ions and ascorbic acid (Fe2+/ Asc) to mouse sperm suspensions increases the formation of thiobarbituric acid-reactive substances (TBARS), an indicator of lipid peroxide breakdown products, without significantly affecting the level of sulfhydryl groups. In the presence of Fe2+/Asc concentrations above > 0.4/2.0 mM, spermatozoa become immotile. However, at concentrations < or = 0.4/2.0 mM of Fe2+/Asc, i.e., conditions in which the TBARS formation is increased by < or = 4.6-fold over that of controls, motility remains unaffected for up to 3 hours. In the presence of 0.4/ 2.0 mM Fe2+/Asc, treated spermatozoa increase their fertilizing potential by 50%, as measured by the formation of two-cell embryos. This increase is not caused by improvements in sperm motility parameters (percentage, linearity, velocity, hyperactivation) or sperm capacitation. On the other hand, there is a significant increase in the capacity of mouse spermatozoa to bind to homologous zona pellucida. In conclusion, mild peroxidative conditions, that increase lipid peroxide formation 4.6-fold without significantly modifying free sulfhydryl groups and sperm motility parameters, improve the fertilizing potential of spermatozoa by increasing their binding capacity to zona pellucida.

Chromatin packaging and morphology in ejaculated human spermatozoa: evidence of hidden anomalies in normal spermatozoa.

Abstract: This study aimed to investigate the association between anomalies in sperm chromatin packaging, morphology and fertilization in patients undergoing routine in-vitro fertilization (IVF) or subzonal insemination (SUZI). Sperm chromatin packaging was assessed using chromomycin A3 (CMA3), a fluorochrome specific for guanine-cytosine rich sequences of DNA. One hundred to 150 sperm cells were assessed in 55 patients to compare sperm chromatin packaging and morphology to fertilization after IVF or SUZI. When the morphology and CMA3 fluorescence of individual spermatozoa was assessed, > 75% of the macrocephalic sperm fluoresced in all patients. In contrast, a mean of 37% of the spermatozoa with normal morphology fluoresced in IVF patients compared with 58% of the normal spermatozoa in male factor patients treated by SUZI. SUZI patients displaying a high fluorescence (> 70%) in their spermatozoa also had a significantly lower fertilization rate. Lower packaging quality in morphologically normal spermatozoa may represent a major limiting factor in the fertilizing ability of male factor patients. This study confirms that a high percentage of CMA3 positivity is present in certain forms of male factor infertility and that such a test may be used to distinguish separate populations in morphologically normal spermatozoa.

Influence of Escherichia coli on motility parameters of human spermatozoa in vitro

Abstract: The influence of E. coli on human sperm motility was studied in vitro. Semen samples were prepared by a swim-up technique and adjusted to 22 x 10(6) spermatozoa/ml. Samples were then inoculated with different concentrations of a uropathogenic strain of E. coli, serotype 06, with initial sperm/bacteria ratios varying between 10:1 and 10000:1. Motion parameters were analysed by computer-aided motility analysis directly, and 2, 4 and 6 h after inoculation. In a second series of experiments, bacterial replication was inhibited by addition of chloramphenicol. In a third series, the effect of E. coli culture filtrates on sperm motility was investigated. The direct inhibitory effect of E. coli on progressive motility of spermatozoa was found to depend upon the bacterial concentration. A distinct inhibitory effect was observed only at a sperm/bacteria ratio of approximately 1, achieved by growth of E. coli during the experiments. For modality of motion, no distinct changes were observed. When growth of bacteria was prevented by chloramphenicol, no inhibitory effect on sperm motility was detected. Sperm motility was not inhibited by E. coli culture filtrates. Analysis by electron microscopy revealed multiple adhesions of E. coli to spermatozoa, causing variable ultrastructural damage as probable morphological correlates of immobilization.

Cryopreservation of spermatozoa: a 1996 review

Abstract: Both the ability to freeze human spermatozoa and the possibility of pregnancy following intrauterine insemination have existed for >40 years. There have been a number of improvements during that time concerning the methods of freezing and thawing human spermatozoa. Initially, the use of the cryoprotective properties of glycerol allowed a major improvement; subsequently, changes were mainly empirical. It was a long time before specific cryobiological studies were undertaken. However, the necessity for these became apparent with the partial recovery or sometimes loss of motility after freezing either subfertile semen before chemotherapy or radiotherapy, or spermatozoa collected from non-physiological situations (epididymal or testicular spermatozoa). The main trends in improvement have defined end-points other than the percentage of motility recovery or the assessment of ultrastructural damage. More sensitive criteria of the objective assessment of motility, energy status, damage to the plasma membrane or to subcellular elements, chromatin stability and chromosomal damage have been proposed as complementary end-points to better assess sperm cryopreservation. A different approach was related to the biochemical environment and physical conditions imposed on spermatozoa during the freezing and thawing process. Biochemical changes were assessed following different combinations of various extenders which attempted either to better preserve some parameter or to avoid the tendency towards drastic increase in osmotic pressure. Analysis of physical conditions was linked to the rate of cooling, freezing and warming, and was based on cryobiological studies. Finally, even though such improvements are not negligible, many questions remain unanswered. The extensive use of frozen spermatozoa during assisted reproductive techniques, together with the development of assisted fertilization using surgically collected spermatozoa, creates the need for additional studies to improve the cryopreservation of human spermatozoa.

Cytokine levels in the seminal plasma of infertile males

Abstract: Cytokines released by various cell subsets in the male urogenital tract are capable of markedly influencing sperm function and fertility. We determined the cytokine content in the seminal plasma of patients with unexplained infertility and correlated the results with urogenital infections and sperm parameters. Routine sperm parameters, bacterial culture of seminal plasma and blood follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone were obtained from 14 infertile males and 8 healthy control subjects. Interleukin 1 beta (IL-1 beta), interleukin 6 (IL-6), and tumor necrosis factor alpha (TNF alpha) levels in the seminal plasma were measured by enzyme-linked immunosorbent assay (ELISA). IL-1 beta, IL-6, and TNF alpha levels in the seminal plasma were negatively correlated with the number of progressively motile sperm, but there was no correlation with total sperm counts, viability, pH, morphological alterations, type of abnormality, and hormone parameters. Cytokine levels were significantly elevated in seminal plasma exhibiting bacterial or mycoplasmal infections of the urogenital tract. Urogenital infections lead to an release of inflammatory cytokines, most probably by immunocompetent cells of the lymphocyte/macrophage origin. Cytokines such as IL-1, IL-6, and/or TNF alpha might influence sperm motility via direct or indirect effects, resulting in reduced mucosa penetration properties. Therefore, our data suggest that cytokines may be involved in reduced male fertility.

Aggressive sperm immobilization prior to intracytoplasmic sperm injection with immature spermatozoa improves fertilization and pregnancy rates.

Abstract: This study was conducted to determine whether the mode of sperm immobilization prior to intracytoplasmic sperm injection (ICSI) influences fertilization by immature spermatozoa. Of the 837 ICSI cycles evaluated, 81 were performed with epididymal or testicular spermatozoa; 35 cycles with epididymal spermatozoa immobilized in the standard fashion resulted in fertilization and pregnancy rates of 48.3 and 51.4% respectively. When a more aggressive sperm immobilization technique (i.e. permanently crimping the sperm flagellum between the midpiece and the rest of the tail) was applied in 17 cycles, the resultant fertilization and pregnancy rates were significantly (P < 0.05) higher: 82.0 and 82.4% respectively. Similar increases in fertilization and ensuing pregnancy rates were also observed in ICSI cycles with the aggressive immobilization of frozen-thawed epididymal spermatozoa (eight cycles) versus standard immobilization (16 cycles). However, the fertilization rates for ICSI using testicular spermatozoa (five cycles) were basically the same, regardless of the immobilization technique. Furthermore, for ejaculated spermatozoa (756 cycles), the fertilization rates following aggressive sperm immobilization were also positively affected (73.4%), although no statistical differences in the clinical pregnancy rates were found. Because aggressive immobilization appears to affect sperm membrane permeabilization, the enhanced fertilization patterns observed in immature spermatozoa following aggressive immobilization may suggest a different membrane constitution in these spermatozoa. These findings indicate that immature gametes may require additional manipulation to enhance the post-ICSI events essential for adequate nuclear decondensation.

Primate sperm contain protein phosphatase 1, a biochemical mediator of motility.

Abstract: Sperm motility initiation, capacitation, and hyperactivation are modulated by an interplay of intracellular Ca 2+ , cAMP, and pH. Mechanisms by which these mediators alter sperm function have not been elucidated but may involve reversible alterations in regulatory protein phosphorylation. Studies were designed 1) to investigate the influence of the protein phosphatase (PP) inhibitor calyculin A (CA) on human sperm motility and 2) to characterize the CA-sensitive PP and its endogenous regulators in human and rhesus monkey sperm. CA (50 nM) treatment of human sperm resulted in an increase in percentage motility and an acceleration in mean path velocity. Inhibition of either protein phosphatase-1 (PP1) or protein phosphatase-2A (PP2A) could be responsible for this motility stimulation, since both of these phosphatases are sensitive to nanomolar quantities of CA. PP activity in human In = 4) and rhesus monkey (n = 4) sperm sonicates was measured using [ 32 P1-phosphorylase-a, the preferred substrate for PP1 and PP2A, in the absence of divalent cations. Human (6.2 + 4.5 x 10 -2 mU/10 6 sperm) and monkey (4.3 + 0.8 x 10 - 2 mU/10 6 sperm) sonicates contained activity tentatively identified as PP1 on the basis of inhibition profiles in okadaic acid (OA) and CA. Western blot analysis with antibodies against various isoforms of PP1 subsequently documented the presence of PP1, 2 in human and monkey sperm. PP1 activity in most tissues is regulated by the heat-stable inhibitors 11 or 12. Sperm sonicates contained inhibitor activity similar to 12 as well as glycogen synthase kinase-3 (GSK-3) activity, which is involved in the activation of the PP1-12 complex. These results indicate, for the first time, that human and rhesus monkey sperm contain PP1 and regulators of PP1 and that inhibition of PP1 activity by CA can enhance motility.

Pregnancies after intracytoplasmic sperm injection with cryopreserved testicular spermatozoa

Abstract: In 25 patients (14 suffering from obstructive azoospermia, six from non-obstructive azoospermia, three from asthenoazoospermia and two from absence of ejaculation) spermatozoa were extracted from testicular biopsies. Intracytoplasmic sperm injection (ICSI) with fresh testicular spermatozoa was performed in 18 cases ; spermatozoa in excess were cryopreserved in pills. No pregnancies were achieved. In the remaining seven patients, testicular spermatozoa were retrieved and cryopreserved during a diagnostic testicular biopsy. After thawing, sperm motility was assessed in 17 cases (68%), and 18 ICSI with cryopreserved testicular spermatozoa were performed. The mean two-pronuclear (2PN) fertilization rate was 59%, the mean cleavage rate was 92%, and six clinical pregnancies were achieved, all of them still ongoing (pregnancy rate 33%). A comparison of the results of ICSI carried out with fresh or cryopreserved testicular spermatozoa showed that the mean 2PN fertilization rates per cycle (53 compared with 55%), mean cleavage rates per cycle (99 compared with 96%) and embryo quality were not significantly different. In conclusion, cryopreservation of testicular spermatozoa is feasible, even in patients with non-obstructive azoospermia, and the results of ICSI with frozen-thawed testicular spermatozoa are similar to those obtained using fresh testicular spermatozoa. Cryopreservation of testicular spermatozoa may avoid repetition of testicular biopsies to retrieve spermatozoa for successive ICSI cycles in patients in whom the only source of motile spermatozoa is the testicle.

Andrology: Effects of sperm activity on zinc and fructose concentrations in seminal plasma

Abstract: Attempts to correlate zinc and fructose concentrations in seminal plasma with andrological parameters have produced inconsistent results. To assess further this relationship, a prospective study was performed measuring zinc and fructose concentrations in seminal plasma in 1178 patients referred for fertility treatment. Seminal analysis was performed with biochemical measurements of seminal zinc and fructose. The main outcome measures were the correlation between motile sperm concentration and seminal zinc and fructose concentrations. Zinc concentrations were not influenced by the motile sperm concentration (r = 0.039). Fructose concentrations were found to be negatively correlated with motile sperm concentration (r = 0.062). We conclude that seminal plasma zinc is an unreliable marker of spermatogenic activity. While there does appear to be a negative correlation between seminal plasma fructose concentrations and motile sperm concentration this relationship is far from linear. Due to the biochemical complexity of seminal fluid attempts to perform such simple correlations between seminal plasma components and andrological parameters are likely to produce inconsistent results and their role in the assessment of sperm function must therefore be called into question.

Regulation of the motility and metabolism of spermatozoa for storage in the epididymis of eutherian and marsupial mammals

Abstract: The present review examines the mechanisms involved in sperm storage in the epididymis of therian mammals in terms of the supply of energy substrate and the regulation of motility and metabolism. Lipids, glucose, lactate and glycerol are possible metabolic substrates for sperm in the epididymis, but the role of these is uncertain and it may differ between marsupials and eutherians. Sperm are normally immotile in the epididymis, but ram and rabbit sperm may have an uncoordinated motility. Sperm metabolism is suppressed but is probably not strongly coupled to motility. Work on diluted sperm indicates that cyclic adenosine monophosphate, Ca2+, and pH play roles as intracellular messengers controlling the motility and metabolism of sperm, but no first messenger has been identified. A number of mechanisms of suppressing sperm motility and metabolism in the epididymis are considered, including a collective autoregulation, oxygen tension, osmotic pressure, viscosity and the extracellular concentration of H+, Ca2+, Na+, HCO3- and carnitine. However, there is no conclusive evidence for any of the mechanisms and there is clearly some variation between species in the mechanism of suppressing sperm activity. Sperm activation stimulates motility and a 4-5-fold increase in respiration rate that has not been reversed without compromising viability. Following activation, respiration supported by endogenous and/or exogenous substrates is much higher in marsupial than eutherian sperm, and marsupial sperm do not show a large stimulation of respiration on the addition of exogenous substrate, as is characteristic of most eutherian sperm.

Purification and characterization of the active precursor of a human sperm motility inhibitor secreted by the seminal vesicles: identity with semenogelin.

Abstract: Human seminal plasma contains a sperm motility inhibitor that originates from seminal vesicles as a precursor form. This precursor is degraded into smaller peptides by prostatic proteases shortly after ejaculation. The seminal plasma sperm motility inhibitor (SPMI) precursor was purified by a combination of cation-exchange chromatography on S-Sepharose followed by C4 reverse-phase high-performance liquid chromatography directly from seminal vesicle fluid or washed seminal coagulum. The purification procedure yielded a protein of apparent homogeneity, with a molecular mass of 52 kDa by SDS-PAGE. It migrated as a 105-kDa protein by molecular sieving under denaturing conditions. The purified SPMI precursor was digested by the prostatic protease prostate-specific antigen (PSA), causing a 76 +/- 4% drop in biological activity and transformation into low molecular mass SPMI polypeptides (5-20 kDa) similar to those observed in liquefied semen. The N-terminal amino acid sequences of three degradation peptides were obtained by Edman degradation and found to correspond to residues 45-50, 85-90, and 137-143 of semenogelin, a protein characterized as the major structural component of semen coagulum. The amino acid composition of SPMI precursor was found to be almost identical to that of semenogelin. Moreover, the mass of the precursor was estimated at 49,620 daltons by electrospray-ionization mass spectrometry, a value in close agreement with the expected mass of semenogelin according to its cDNA sequence. The SPMI precursor was found to inhibit sperm motility in a dose-dependent manner, with complete immobilization at 500 U/ml of SPMI. The motility of completely immobilized spermatozoa was partially recovered after washing of the cells. The results suggest that SPMI precursor is the major component of the seminal vesicle secretions and seminal coagulum. It can be degraded by PSA in a manner reminiscent of its processing in whole semen. Taken together these results indicate that the SPMI precursor is semenogelin and that intact semenogelin can immobilize spermatozoa.

Viability of ram spermatozoa in relation to the abstinence period and successive ejaculations

Abstract: For successful fertilization, a functionally constituted sperm plasma membrane is necessary, and this is clearly dependent on the sperm maturation process. The latter involves a series of complex changes which result from a sequence of events occurring at different points within the epididymis. The transit time through the epididymis can be influenced by external factors such as sexual stimulus and ejaculatory frequency. The present work was undertaken to determine changes in ram sperm viability and other sperm quality characteristics in relation to ejaculatory frequency. Three successive ejaculates were collected from rams during three different abstinence periods (collected every day, every 2 days and every 3 days). Cell viability (membrane integrity determined by fluorescence staining), progressive individual motility, and other in vitro parameters of sperm quality were evaluated. Second ejaculates showed the highest cell viability of the three periods studied, and increased as the abstinence period lengthened. The maximum proportion of viable cells (average 60%) was obtained in the second ejaculate after an abstinence period of 3 days. Likewise, overall and progressive individual motilities were higher in second ejaculates, the maximum value being 70% after 3 days of abstinence. The percentage of damaged or acrosome-reacted spermatozoa was greater after 1 day of abstinence than after the other periods analysed, whereas the first ejaculate showed the highest value in all periods. Differences in ejaculate volume were correlated strongly with both variables considered (abstinence period and ejaculate number). In the third ejaculate, about 27% more volume was obtained after 3 days of abstinence than after abstinence for 1 or 2 days. Sperm concentration increased significantly as the abstinence period lengthened, and also decreased significantly with ejaculate number in all cases. Therefore, the total number of spermatozoa in the ejaculate was clearly dependent on the abstinence period and the ejaculate number. In conclusion, the results obtained suggest that using the second and/or a mixture of second and third ejaculates would improve the results in artificial insemination and in fertility studies. In addition, the use of better quality semen would facilitate progress in semen cryopreservation studies.

Kobe earthquake and reduced sperm motility

Abstract: We investigated a possible relationship between the Kobe earthquake (January 17, 1995) and the quality of semen. We assessed sperm concentration and motility of 27 male patients who had a concentration of more than 30 million/ml and >40% sperm motility within 5 months before the earthquake. Twelve male patients from districts with a magnitude of 6, five patients whose houses received no damage showed no distinct changes in sperm concentration and motility. In contrast, 10 patients whose houses were partially or completely destroyed showed significantly (P < 0.001) lower sperm motility after the earthquake than before, although no significant difference of sperm concentration could be observed. Of these latter 10 patients, seven could be followed. In six patients, sperm motility was restored between 2 and 9 months after the earthquake; the sperm motility in one patient, whose father died a victim of the house crash, has not yet recovered. Thus, the acute stress resulting from such a catastrophic earthquake could be a possible cause of reduced sperm motility.

Efficacy of intracytoplasmic sperm injection using intentionally cryopreserved epididymal spermatozoa

Abstract: Microsurgical epididymal sperm aspiration was a great advance in the therapy of patients with non-reconstructable, obstructive azoospermia, most notably congenital bilateral absence of the vas deferens. Using conventional in-vitro fertilization, pregnancies were rarely achieved because the rate of oocyte fertilization was extremely poor. However, the use of retrieved spermatozoa in conjunction with intracytoplasmic sperm injection (ICSI) has dramatically increased the likelihood of embryo formation. Typically, sperm and oocyte harvesting are performed simultaneously. We have investigated whether frozen-thawed spermatozoa work as well as fresh spermatozoa. When we had concluded from our own population of patients (groups I and II) that they did, we adopted a policy of aspirating spermatozoa, primarily cryopreserving them and using them for ICSI at a later date. We found the fertilization rates of this latter cohort of patients (group III) to be excellent (37% per oocyte), and the ongoing pregnancy rate is quite satisfactory (40% per couple, 29% per cycle). We offer this approach as an alternative to the traditional scheme because it markedly eases the burden of partner scheduling on both the couple and the clinicians involved. In addition, assurance of the availability of male partner spermatozoa can be attained prior to beginning ovulation induction.