Showing papers on "Sperm motility published in 1995"

The result of intracytoplasmic sperm injection is not related to any of the three basic sperm parameters.

Abstract: High success rates have been reported for the use of intracytoplasmic sperm injection (ICSI) in alleviating essentially andrological infertility. However, neither the relationship between any of the sperm parameters and the result of ICSI nor the minimal sperm requirements for ICSI have been investigated so far. In this paper, our objective was therefore to study the relationship between three basic sperm parameters (total sperm count, sperm motility and morphology) and the outcome of ICSI by retrospective analyses of fertilization, embryo development and pregnancy rates in 966 micro-injection cycles, performed with ejaculated semen. The results showed that there was no important influence from either the type or the extent of sperm impairment on the outcome of ICSI. Even in the most extreme cases of male-factor infertility, where cryptozoospermia or total astheno- or total teratozoospermia was diagnosed in the initial semen sample, high fertilization and pregnancy rates were obtained by ICSI. Only one condition had a strongly negative influence on the result of ICSI: where an immotile (presumably dead) spermatozoon was injected into the oocyte. Thus the only ultimate criterion for successful ICSI is the presence of at least one living spermatozoon per oocyte in the pellet of the treated semen sample used for micro-injection.

Redox regulation of tyrosine phosphorylation in human spermatozoa and its role in the control of human sperm function

Abstract: The redox status of human spermatozoa was found to have a profound influence on the fertilizing potential of these cells in association with qualitative and quantitative changes in the patterns of tyrosine phosphorylation. In general, oxidizing conditions enhanced tyrosine phosphorylation and stimulated sperm function, whereas reducing conditions had the opposite effect. Unstimulated human spermatozoa exhibited low levels of spontaneous acrosomal exocytosis and sperm-oocyte fusion and minimal reactive oxygen species generation, while phosphotyrosine expression was largely confined to a single protein of 116 kDa. However, if the spermatozoa were exposed to oxidizing conditions through the addition of exogenous H2O2, or the stimulation of endogenous NADPH-dependent reactive oxygen species generation, then a dramatic increase in tyrosine phosphorylation was observed (major phosphotyrosyl bands at 222 kDa, 200 kDa, 159 kDa, 133 kDa, 116 kDa and 82 kDa) in concert with the functional activation of the spermatozoa. A causal association between reactive oxygen species generation, tyrosine phosphorylation and sperm function was indicated by studies with the ionophore, A23187, which induced high rates of spermoocyte fusion together with enhanced rates of reactive oxygen species production and the increased expression of phosphotyrosyl proteins. This functional response to A23187 could be abrogated, without any concomitant change in sperm motility or viability, by using membrane permeant thiols or catalase to suppress the reactive oxygen species-induced increase in phosphotyrosine expression. The fact that the biological responses of human spermatozoa to biological agonists (recombinant human ZP3 and progesterone) could also be inhibited by catalase indicated the general relevance of these findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevention of osmotic injury to human spermatozoa during addition and removal of glycerol.

Abstract: Use of a cryoprotective agent is indispensable to prevent injury to human spermatozoa during the cryopreservation process. However, addition of cryoprotective agents to spermatozoa before cooling and their removal after warming may create severe osmotic stress for the cells, resulting in injury. The objective of this study was to test the hypothesis that the degree (or magnitude) of human sperm volume excursion can be used as an independent indicator to evaluate and predict possible osmotic injury to spermatozoa during the addition and removal of cryoprotective agents. Glycerol was used as a model cryoprotective agent in the present study. To test this hypothesis, first the tolerance limits of spermatozoa to swelling in hypo-osmotic solutions (iso-osmotic medium diluted with water) and to shrinkage in hyperosmotic solutions (iso-osmotic medium with sucrose) were determined. Sperm plasma membrane integrity was measured by fluorescent staining, and sperm motility was assessed by computer-assisted semen analysis before, during and after the anisosomotic exposure. The result indicate firstly that motility was much more sensitive to anisosmotic conditions than membrane integrity, and secondly that motility was substantially more sensitive to hypotonic than to hypertonic conditions. Based on the experimental data, osmotic injury as a function of sperm volume excursion (swelling or shrinking) was determined. The second step, using these sperm volume excursion limits and previously measured glycerol and water permeability coefficients of human spermatozoa, was to predict, by computer simulation, the cell osmotic injury caused by different procedures for the addition and removal of glycerol. The predicted sperm injury was confirmed by experiment. Based on this study, an analytical methodology has been developed for predicting optimal protocols to reduce osmotic injury associated with the addition and removal of hypertonic concentrations of glycerol in human spermatozoa.

Analysis of sperm movement in relation to the oxidative stress created by leukocytes in washed sperm preparations and seminal plasma.

Abstract: The addition of luminol to unprocessed semen samples resulted in the generation of chemiluminescent signals, the intensity of which was highly correlated with the level of leukocyte contamination. Despite the spontaneous oxidant-generating capacity of seminal leukocytes, no correlations were observed between leukocyte contamination and the fertility status of the subjects or any aspect of the semen profile, including the motility of the spermatozoa or their performance in a hyaluronate penetration assay. Luminol-dependent chemiluminescence and leukocyte contamination were also correlated in washed sperm suspensions prepared either by repeated centrifugation or on discontinuous Percoll gradients. However, in such sperm suspensions, the spontaneous generation of oxidants by contaminating leukocytes (> 2 x 10(4) leukocytes/ml) was invariably associated with a decreased capacity for movement. Moreover, causative associations between leukocyte contamination, reactive oxygen species generation, lipid peroxidation and impaired sperm motility were revealed by experiments involving the selective addition or removal of activated leukocytes. From these observations we can conclude that low concentrations of leukocytes are a common feature of the human ejaculate and can impair sperm function, particularly in the absence of seminal plasma. These findings have implications for our understanding of the importance of leukocytospermia in defining the fertility of human spermatozoa in vivo and in vitro.

Andrology: Effects of nitric oxide on human spermatozoa: evidence that nitric oxide decreases sperm motility and induces sperm toxicity

Abstract: Endogenous nitric oxide (NO) is an important functional mediator in several physiological systems, including the reproductive system. However, when generated in excessive amounts for long periods, mainly during immunological reactions, NO is cytotoxic and cytostatic for invading microbes, as well as for the cells generating it and the tissues present around it. Since infertility associated with urogenital tract infection in males and females is also accompanied by reduced sperm motility and viability, it is possible that reduced fertility in these patients is due to NO-induced sperm toxicity. We therefore evaluated the direct effects of NO, chemically derived from S-nitroso-N-acetylpenicillamine (SNAP, 0.012-0.6 mM) and sodium nitroprusside (SNP, 0.25-2.5 mM), on the motility and viability of human spermatozoa. Furthermore, we tested whether inhibition of NO synthesis prevents sperm motility and viability by incubating washed total cells present in the semen (spermatozoa, round cells) with N-nitro-L-arginine-methyl-ester (L-NAME), a NO synthesis inhibitor. Treatment of purified spermatozoa with SNAP or SNP decreased forward progressive sperm motility and straight line velocity, and also increased the percentage of immotile spermatozoa in a concentration-dependent manner. Furthermore, the percentage of immotile spermatozoa positively correlated with the percentage of dead spermatozoa. In contrast to freshly prepared SNAP, SNAP preincubated for 48 h had no effect on the motility and viability of the spermatozoa. Furthermore, as compared to untreated controls, a significantly higher percentage of forward progressive sperm motility as well as viability (P < 0.05) was maintained in washed semen incubated with L-NAME (0.15 mM).(ABSTRACT TRUNCATED AT 250 WORDS)

Sperm motility hyperactivation facilitates penetration of the hamster zona pellucida.

Abstract: These experiments were conducted to determine whether or not sperm motility hyperactivation facilities penetration of the zona pellucida of the oocyte. Two approaches were used. For the first, hamster sperm were incubated for 4.0-4.25 h in a capacitating medium that contained either 2.9 or 25.0 mM sodium bicarbonate. In these media, sperm became equally capacitated as evidenced by their ability to undergo the acrosome reaction when exposed to lysophosphatidyl choline or intact zonae pellucidae; however, sperm became hyperactivated only in the medium containing 25.0 mM bicarbonate. When these sperm were added to cumulus-free oocytes in vitro, only 2 of 88 oocytes were penetrated by sperm preincubated in 2.9 mM bicarbonate, while 31 of 86 oocytes were penetrated by sperm in 25.0 mM bicarbonate. It was found that equal numbers of sperm were bound to the oocytes and that equal numbers were acrosome-reacted on the surface of the zonae in the two media. For the second approach, sperm were incubated in a capacitating medium containing 25 mM bicarbonate. When > 70% were hyperactivated, aliquots were added to three sets of oocytes. After 10 min had been allowed for sperm to attach and acrosome-react, inhibitors of hyperactivation were added and the sperm and oocytes were incubated for an additional 20 min before fixation and examination for zona penetration. In the dishes treated with the inhibitors verapamil or Cd2+, 1 of 42 and 0 of 42 oocytes were penetrated, respectively, compared with 25 of 40 in controls. Therefore, it appears that hyperactivation facilitates penetration of the hamster zona pellucida.

Mitochondrial deoxyribonucleic acid 4977-bp deletion is associated with diminished fertility and motility of human sperm.

Abstract: The accumulation of mitochondrial DNA (mtDNA) mutations has been suggested to be an important contributor to human aging and degenerative diseases. In previous studies, we found an age-dependent increase of mtDNA mutations in various human tissues. Sperm motility is one of the determinants of male fertility. The possible relationship between mtDNA deletions and diminished fertility and motility of sperm was explored in the present study. We examined accumulation of the 4977-bp mtDNA deletion in spermatozoa obtained from patients with infertility or subfertility and compared these values with those of normal individuals. Using polymerase chain reaction (PCR) techniques, we determined the frequency of occurrence and the proportion of mtDNA with the 4977-bp deletion in human spermatozoa with different motilities. Human spermatozoa were separated by self-migration in Percoll gradients into five fractions with different motility scores. The highest frequency of occurrence of the 4977-bp mtDNA deletion was found in sperm in the fraction with the lowest motility. The results revealed a negative correlation between sperm motility and the proportion of 4977-bp-deleted mtDNA. Furthermore, we found a significantly higher incidence of the 4977-bp mtDNA mutation in patients with asthenospermia, oligospermia, and primary infertility compared to normal individuals. These findings suggest that mtDNA mutations may play an important role in some pathophysiological conditions in human spermatozoa.

Low levels of nitric oxide promote human sperm capacitation in vitro.

Abstract: The influence of nitric oxide on human sperm hyperactivation and capacitation, as well as its mechanism of action and its possible origin from spermatozoa were studied. Percoll-washed spermatozoa from healthy volunteers were incubated in Ham's F-10 medium supplemented or not with the nitric oxide-releasing agents, diethylamine-NONOate or spermine-NONOate, in combination or not with superoxide dismutase or catalase (scavengers for the superoxide anion and for hydrogen peroxide, respectively), or with sodium nitrate, sodium nitrite, or preincubated NONOates. Sperm hyperactivation, capacitation, and nitric oxide synthase activity were determined. High concentrations (0.3 to 1 mM) of NONOates reduced sperm motility. However, a lower concentration (0.1 mM) of the two NONOates had no effect on the percentage of sperm motility or of hyperactivation but resulted in a significant increase in sperm capacitation (24% +/- 4%) when compared to that of control spermatozoa (Ham's F-10 alone, 12% +/- 2%). Nitric oxide released by the NONOates appeared responsible for this effect because sodium nitrate or nitrite or preincubated NONOates (to exhaust the formation of nitric oxide) had no influence on sperm capacitation. Catalase, but not superoxide dismutase, abolished the capacitating action of the NONOates. No nitric oxide synthase activity was detected in spermatozoa, whether they were in their basal state or already capacitated. Furthermore, the nitric oxide synthetase inhibitor L-NG nitroarginine methyl ester did not block sperm capacitation induced by fetal cord serum ultrafiltrate. It is therefore concluded that, although spermatozoa do not possess detectable nitric oxide synthase activity, low levels of nitric oxide induce human sperm capacitation, and this action likely involves hydrogen peroxide.

Change in intracellular K+ concentration caused by external osmolality change regulates sperm motility of marine and freshwater teleosts

Abstract: We previously demonstrated that osmolality isotonic to the seminal plasma suppresses sperm motility in marine and freshwater teleosts, and exposure of sperm to hypertonicity of sea water or hypotonicity of fresh water, respectively, induces the initiation of sperm motility at spawning. The motile sperm became immotile by return of osmolality to the isotonic osmolality both in a marine teleost, the puffer fish, and a freshwater teleost, the zebrafish. The initiation and termination of sperm motility could be repeated several times by changing surrounding osmolality in both species. In demembranated sperm, motility was suppressed by a K+ concentration equivalent to the seminal salt concentration in both puffer and zebrafish. Demembranated puffer sperm were reactivated when K+ concentration of the reactivating solution increased. Conversely, initiation of motility in the demembranated zebrafish sperm was induced by decreasing K+ concentration. The initiation and termination of the demembranated sperm were alternately repeated by changing K+ concentration of the reactivation solution in both species. Furthermore, intracellular K+ concentration rose when sperm motility of the puffer was initiated in hypertonic solutions. These results suggest that change in external osmolality is converted into change in intracellular K+ concentration, and that the change affects the flagellar axoneme as a signal to initiate or terminate sperm motility. The initiation and termination of motility in the demembranated puffer sperm were caused at a high pH and a low pH of the reactivating solution, respectively, suggesting the contribution of intracellular pH in the regulation of flagellar motility.

Capacitation In Vitro of Stallion Spermatozoa: Comparison of Progesterone‐Induced Acrosome Reactions in Fertile and Subfertile Males

Abstract: Mammalian sperm that have completed capacitation are capable of undergoing the acrosome reaction in response to a number of biological and chemical stimuli. In the present report, we have investigated the ability of progesterone to stimulate acrosome reactions of stallion sperm capacitated in vitro. Motile sperm were selected by a two-layer Percoll gradient centrifugation and were incubated in TALP medium modified by the 1:1 (v/v) addition of TEST-yolk medium for 5 hours at 39 degrees C, under 5% CO2 in humidified air. Sperm incubated in vitro in TALP-TEST medium had a higher percentage of acrosome reactions following the addition of progesterone (3.18 mumol/L) compared to controls (P < 0.05). Furthermore, sperm from stallions classified as fertile on the basis of breeding history had higher percentages of progesterone-induced acrosome reactions in comparison with stallions classified as subfertile (P < 0.05). Acrosome reactions were assessed routinely by fluoresceinated lectin binding, but the physiological appearance of induced acrosome reactions was confirmed at the ultrastructural level by transmission electron microscopy. We conclude that 1) TALP-TEST medium supports stallion sperm capacitation in vitro, 2) progesterone-induced acrosome reactions are physiological, and 3) sperm from fertile stallions may be more responsive to progesterone-induced acrosome reactions than those of subfertile stallions. This is the first report in a nonhuman species that differences exist between the sperm of fertile and subfertile males in the ability to capacitate and acrosome react in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Odorant receptors and desensitization proteins colocalize in mammalian sperm.

Abstract: The identification of transcripts encoding putative olfactory receptors in mammalian germ cells (1) has generated the hypothesis that olfactory receptors may serve a chemosensory role in sperm Chemotaxis during fertilization. We have sought to identify and localize these receptors and their regulatory machinery in rat sperm in order to gain further insight into mammalian sperm Chemotaxis and odorant receptor physiology. We conducted reverse transcription-polymerase chain reaction (RT-PCR) using degenerate primers directed against sequences conserved across members of the known odorant receptor family to identify transcripts from testis and round spermatids. Western analysis and immunohistochemistry were performed using antibodies raised against two peptide sequences conserved among odorant receptors and using fusion protein antibodies to G-protein receptor kinase 3 (GRK3/βARK2) and β-arrestin2. We detected transcripts encoding putative odorant receptors in both testis and round spermatids of the adult rat. Restriction digests of the PCR products demonstrated the existence of multiple gene products. Two anti-odorant receptor antibodies specifically recognized a 64 kD band in rat sperm preparations by Western blot. The proteins GRK3 and β-arrestin2, implicated in olfactory desensitization, were detected in sperm cytosolic extracts using Western analysis. Immunohistochemistry colocalized putative odorant receptors, GRK3 and β-arrestin2 to elongating spermatids in the testis and to the midpiece of mature sperm.

Evaluation of reproductive capacity in germ cell tumor patients following treatment with cisplatin, etoposide, and bleomycin.

Abstract: PURPOSETo evaluate the infertility rate in patients with germ cell tumors receiving chemotherapy with cisplatin, etoposide (VP-16), and bleomycin (PVP16B).PATIENTS AND METHODSThirty patients were evaluated. All patients had undergone chemotherapy with two to four cycles of PVP16B. A single semen analysis was performed 24 to 78 months following initiation of chemotherapy. All 30 patients were continuously disease-free. Eight of these patients had also undergone nerve-sparing retroperitoneal lymph node dissection (RPLND).RESULTSThe median sperm concentration was 33.9 x 10(6), with a median volume of 3.2 mL. The median total sperm count was 86.4 x 10(6). Oligospermia (< 40 x 10(6) total sperm count) was found in 13 patients (43%), including six (20%) who were azoospermic. There was a high incidence of morphologically abnormal sperm, with only one patient having more than 50% normal spermatozoa. Only 13 patients (43%) had sperm motility greater than 50%. Five patients had positive semen antisperm immunoglobul...

Human sperm cryopreservation and reactive oxygen species (ROS) production.

Abstract: The aim of this work was to establish whether cryopreservation procedure can trigger the production of Reactive Oxygen Species (ROS) in selected sperm populations. Semen samples were obtained from 45 subjects attending our Department of Medical Pathophysiology. Motile sperm suspensions were obtained by swim-up in Tyrode's salt solution. After dilution with TEST yolk buffer freezing medium, they were cryopreserved in liquid nitrogen. In addition to motility assessment, in basal and freeze/thaw conditions ROS detection and the Hypoosmotic Viability Test were also carried out. In 19 subjects (42.2%) there was already evidence of ROS production prior to cryopreservation, which increased after thawing. In 9 subjects (20.0%) there was no ROS production prior to cryopreservation, however, after freezing/thawing we detected evidence of the presence of ROS. It seems, therefore, that cryoprocedure can indeed provoke or increase ROS production in some semen samples. In ROS producing subjects, the post-show recovery of sperm motility and vitality was significantly lower compared to ROS-free subjects. This was probably due to damage by oxidative stress leading to lipid peroxidation of the sperm membrane. Moreover, in some ejaculates, ROS overproduction or scavenger system failure can be regarded as a cryopathogenetic factor affecting "sperm quality" recovery.

Effect of bovine ampullary and isthmic oviductal fluid on motility, acrosome reaction and fertility of bull spermatozoa

Abstract: Motility, acrosome reaction and oocyte fertilizing ability were assessed for bull spermatozoa after incubation in regional (isthmic or ampullary), bovine oviductal fluid, pooled by stage of the oestrous cycle. Oviductal fluids collected daily from isthmic and ampullary cannulae implanted in the same oviduct were divided into pools, representing two oestrous cycle stages, based on daily serum progesterone concentrations. Ejaculated bull spermatozoa were incubated for 0\p=n-\6h in each type of oviductal fluid. Incubation in isthmic oviductal fluid collected during the nonluteal stage, including oestrus and ovulation, decreased overall sperm motility (from 71.7% motile spermatozoa to 34.0% and both path (78 \g=m\ms \m=-\1versus 86\p=n-\89\g=m\m s\m=-\1) and progressive (74 \g=m\ms\m=-\1versus 83\p=n-\85\g=m\m s\m=-\1) velocities of spermatozoa motion. Spermatozoa incubated in isthmic, non-luteal oviductal fluid had a higher rate and extent of sperm acrosome reaction (213% of control versus 136\p=n-\161%of control by 2 h incubation) compared with spermatozoa incubated in other oviductal fluid types. However, incubation in nonluteal ampullary fluid increased the number of spermatozoa, which were both acrosome reacted and live, and able to fertilize bovine ova (88.7% fertilized versus 75\p=n-\81%).Glycosaminoglycan concentrations were similar among types of oviductal fluid (0.77\p=n-\0.88mg ml \m=-\1). These findings indicate that oviductal fluid differentially affects sperm function, depending on the oviduct region and the stage of the oestrous cycle at which the fluid was obtained.

Sperm motility in turbot, Scophthalmus marimus : initiation of movement and changes with time of swimming characteristics

Abstract: Turbot sperm motility is observed using dark field microscopy and stroboscopic illumination combined with video recording. Sperm motility is triggered by dilution of spermatozoa in sea water or in non ionic media (glucose or saccharose), presenting osmotic pressure ranging from 300 to 2100 mOsmol. The percentage of motile spermatozoa reaches 100% under conditions of osmotic pressure of 300 to 1100 mOsmol and pH close to 8.0. In full sea water, glucose or saccharose solutions an agglutination of spermatozoa is observed; this is prevented by addition of bovine serum albumin (5 mg ml−1). Immediately after transfer in activation solutions, 100% spermatozoa are motile in most samples freshly stripped. This percentage drops suddenly between 15 and 30% after 70 to 100 sec. The beat frequency remains at a constant value of 50 Hz during 40 s post activation and then drops suddenly between 15 and 30 Hz. The spermatozoa velocity is about 200 micrometers s−1 during 30 to 40 s and then declines to a stable value of 100 micrometers s−1 at 50 s post activation. After 1.20 mn, more and more spermatozoa become motionless. The minimum calculated and averaged distance covered during 1.20 min, is about 12 mm. The high performances of turbot spermatozoa motility are interpreted as a compensatory mechanism for the low sperm production.

Asthenozoospermia and the human sperm mid-piece

Abstract: This study provides a quantitative comparison between surface and ultrastructural features of motile spermatozoa in asthenozoospermic and fertile men. The study group consisted of 10 individuals with persistent asthenozoospermia and the controls were 10 fertile donors to a sperm bank. Scanning electron microscopy and image analysis were used to objectively measure sperm mid-piece and tail dimensions. Sperm mid-piece length was significantly shorter (P < 0.01) in asthenozoospermic subjects compared with the controls, with mid-piece width and tail length being comparable. Mid-piece ultrastructure was then examined with the transmission electron microscope and the number of mitochondrial gyres and their configuration recorded. At the ultrastructural level the asthenozoospermic subjects demonstrated significantly fewer mitochondrial gyres (P < 0.001) than their fertile counterparts. Energy for sperm movement is provided by mitochondria and a deficit in these organelles in the sub-fertile cohort provides an explanation for poor sperm function in these subjects.

Fertilizing ability of bovine spermatozoa cocultured with oviduct epithelial cells

Abstract: The effects of bovine oviduct epithelial cell monolayers (OECM), derived from the different segments of the oviduct and under various conditions, on oocyte penetration by bovine sperm were determined by in vitro cell culture techniques. The oocyte penetration rate by sperm treated with OECM+OECM-conditioned medium was 93% (155 of 166). Sperm penetration rates in OECM+fresh medium and in OECM-conditioned Medium alone were 66% (115 of 173) and 52% (87 of 167), respectively, significantly lower (p<0.01) than in OECM+OECM-conditioned medium. However, the percentage of penetrated oocytes in OECM-conditioned Medium alone was significantly higher than in control (11%=16 of 148; p<0.01). In both the OECM+OE conditioned medium and the OECM+fresh medium groups, oocyte penetration rates by sperm cocultured with OECM derived from the isthmic segment were significantly lower than those by sperm cocultured with OECM derived from the ampullary segment (44%=43 of 98 vs. 72%=68 of 94, and 42%=49 of 117 vs. 66%=72 of 110, respectively; p<0.01). Sperm penetration rates were low after insemination in the OECM-conditioned medium alone derived from either the isthmic or the ampullary segments (20%=20 of 100 and 19%=17 of 91, respectively). However, the sperm penetration rate was improved significantly when OECM-conditioned medium was obtained from whole-oviduct OECM (57%=60 of 105; p<0.01). The effect of OECM derived from different segments on ability of sperm binding and maintaining motility was also evaluated in vitro. After 2 h of coculture, more than half the sperm attached to OECM regardless of their origin. Sperm were gradually released from OECM in the whole oviduct and ampullary segments after 3 h of coculture; however, sperm remained attached to isthmic OECM after 12 h of coculture. After 48 h of coculture, the motility of unattached sperm in either isthmic OECM or whole-oviduct OECM was significantly higher than in ampullary OECM (52%±3, 55%±4, and 25%±4, respectively; p<0.01). When sperm were cocultured with ampullary OECM, the percentage of motile sperm was significantly lower from 24 h after coculture than percentages obtained after coculture with whole-oviduct OECM and isthmic OECM (26%±4, 63%±3, and 61%±4, respectively; p<0.01). These results suggest that sperm capacitation was synergistically induced by means of both attachment to OECM and exposure to OEGM-conditioned medium, and that sperm attachment to the ampullary epithelium enhanced sperm capacitation. These results also suggest that the isthmus epithelial cells are important in maintaining sperm motility and that attachment of sperm in the isthmus may act to reduce the number of sperm arriving at the ampulla in vivo

Sperm pairing in the opossum increases the efficiency of sperm movement in a viscous environment.

Abstract: In order to understand why sperm pairing has evolved in most American marsupials, the movement parameters of spermatozoa from Monodelphis domestica were analyzed after incubation in capacitating medium for 15 min, 2 h, and 24 h to induce a proportion of sperm pairs to uncouple. Motility characteristics of paired and single spermatozoa were measured in media of differing composition and viscosity by means of computer-aided semen analysis. In minimum essential medium or in RPMI 1640 medium alone, the absolute mean straight-line and curvilinear velocity values of paired spermatozoa (342 +/- 34 and 361 +/- 19 microns/sec, respectively, at 37 degrees C) were significantly greater than those of single spermatozoa (247 +/- 14 and 319 +/- 16 microns/sec), while mean lateral head displacement for paired spermatozoa (5.6 +/- 2.1 microns) was significantly less than for single spermatozoa (11.4 +/- 2.6 microns). However, when medium was made more viscous with polyvinyl pyrrolidone (0.8-82 poise) and sperm motility was calculated as a percentage of maximum attained velocity (in medium alone), there was no significant difference in straight-line or curvilinear velocity for single or paired spermatozoa in medium of the lowest viscosity (0.8 poise). In contrast, paired spermatozoa in medium of higher viscosity (above 1.92 poise) maintained straight-line velocity (e.g., 54 +/- 3% of maximum straight-line velocity in medium of 2.28 poise) while single sperm moved in tight circles and exhibited poor straight-line velocity (5 +/- 1% of maximum velocity). The data show that paired spermatozoa exhibit a significant motility advantage over single spermatozoa in a viscous medium.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of dermal application of hexachlorocyclohexane (HCH) on male reproductive system of rat

Abstract: 1. The toxic manifestations of dermally applied hexachlorocyclohexane (50 mg or 100 mg kg-1 body weight day-1, 5 days in a week for 120 days) on testes and sperm of rat have been investigated. 2. The results indicate that exposure of HCH through the dermal route could lead to an alteration in the activities of marker testicular enzymes viz. sorbitol dehydrogenase (SDH), glucose-6-P-dehydrogenase (G6PDH), gamma-glutamyl transpeptidase (gamma-GT) and beta-glucuronidase (beta Gluc.) associated with specific cell types. 3. Significant quantities of HCH and its isomers accumulated in testes as well as sperm of treated rats. 4. HCH exposure also led to a decrease in serum testosterone levels, epididymal sperm count, sperm motility and an increase in the percentage of abnormal sperm. 5. These observations indicate the possibility of adverse effects of HCH on the male reproductive functions of men exposed dermally to this pesticide in industry or during spraying in the field.

Intracellular calcium reaches different levels of elevation in hyperactivated and acrosome‐reacted hamster sperm

Abstract: Calcium plays a role in sperm mo- tility hyperactivation and the acrosome reaction, but the relationship between cytoplasmic calcium (Ca",,) levels in the two states was heretofore unknown. The Ca2+ indica- tor indo-1 was used to detect Ca2+in in moving hamster sperm in two sets of experiments. In the first experiment, activated, hyperactivated, and zona pellucida-induced acrosome-reacted/hyperactivated sperm were analyzed at the time of peak of activity for each state. In the second experiment, sperm in all states were analyzed at one time point. In both sets, mean Ca2+i, in the acrosomal region, postacrosomal region, and flagellar midpiece was greater in hyperactivated sperm than in activated sperm, and in acrosome-reacted/hyperactivated sperm than in unreacted/hyperactivated sperm (P < 0.001). Ca2+in had increased to a greater extent in the midpiece than in the head in hyperactivated sperm, while the reverse was true for acrosome-reacted sperm. Oscillations at the frequency of the flagellar beat cycle were detected chiefly in the proximal flagellar midpiece of acrosome-reacted sperm, as they had been previously reported to occur in activated and hyperactivated sperm. Thus, Ca2+,, may be main- tained at two different elevated levels in sperm, and contin- ues to oscillate after the acrosome reaction. 0 1995 Wiley-Liss, Inc.