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Overview of studies on rat sperm motion analysis using a Hamilton-Thorne Sperm Analyzer--collaborative working study.

This collaborative study was conducted to determine the utility and sensitivity of nine sperm motion parameters generated by a Hamilton-Thorne Sperm Analyzer (HTM-IVOS) for detecting adverse effects of chemicals on sperm motion in rats. The efficacy of sperm motion parameters was investigated using nine reproductive toxicants: adriamycin, alpha-chlorohydrin (3 different studies were carried out), dinoseb, ethylene glycol monoethyl ether, 2,5-hexanedione, sulfasalazine, trimethyl phosphate, and ornidazole. The percentage of motile sperm (% motile sperm), the only parameter expressing the status of semen containing non-motile sperm, detected adverse effects on sperm motion in 9 out of 10 studies. However, weak effects on sperm motion were not detected by this parameter in 4 out of 7 studies in which sperm motion disorders were noted at medium or low dosages. The percentage of progressively motile sperm (% progressive sperm) and the sperm velocity parameters (average path velocity, straight line velocity, and curvilinear velocity) detected adverse effects on sperm motion in all studies. In 7 studies which noted sperm motion disorders at medium or low dosages, weak effects on sperm motion were detected by the % progressive sperm in 5 studies and by the sperm velocity parameters in 6 studies. In 10 studies, amplitude of lateral head displacement (ALH) did not detect adverse effects on sperm motion in 4 studies, and beat cross frequency (BCF) failed to detect adverse effects on sperm motion in 3 studies. Because ALH and BCF show the swimming pattern of spermatozoa as head movement, the characteristics of these parameters are different from the % progressive sperm and the sperm velocity parameters. Straightness (STR) and linearity (LIN), which are secondary parameters calculated from sperm velocity parameters, could not detect adverse effects on sperm motion when the sperm velocity parameters did not detect adverse effects. On the basis of these results, we concluded that the % progressive sperm and sperm velocity parameters are useful and sensitive indicators for detecting adverse effects on sperm motion. However, in the % progressive sperm, setting up a suitable threshold of VAP and/or STR is important to gain further sensitivity for detecting adverse effects on sperm motion. The % motile sperm is useful for assessment of sperm motion disorder, and ALH and BCF are useful for evaluating the swimming pattern of sperm. STR and LIN are not very useful for detecting adverse effects on sperm motion.

Animals↗

Purification and characterization of an anti-sticking factor from goat epididymal plasma that inhibits sperm--glass and sperm--sperm adhesions.

An anti-sticking factor (ASF-I) that showed high affinity for inhibiting adhesion of spermatozoa to glass was isolated from goat epididymal plasma and characterized. The factor was purified approx. 5600-fold and showed a single protein band when examined by non-denaturation and SDS-polyacrylamide gel electrophoresis. The molecular mass and S20w value of ASF-I were approx. 47 kDa and 4.25 S. ASF-I at a concentration of 1 nM showed nearly maximal anti-sticking activity when approx. 60% of the intact spermatozoa were prevented from adhesion to glass and it showed a high degree of protein specificity. Studies with trypsin and glycosidases demonstrated that both the sugar and protein parts of the molecule are essential for its anti-sticking activity. Evidence has been presented to support the view that the outer surface of sperm possesses specific ASF-I receptors that bind to 125I-labelled ASF and mediate cell adhesion to glass. ASF-I also showed high affinity for inhibiting agglutination of corpus-epididymal spermatozoa. The ASF activity was found to be distributed in all the tissues tested and its specific activity was markedly higher in blood plasma than in the tissues. The results suggest that ASF may play an important biological role by serving as a specific inhibitor of cell-substratum and cell-cell adhesions.

Animals↗

Results of microsurgical epididymal sperm aspiration (MESA) ans testicular sperm extraction (TESE) in azoospermic men using intracytoplasmic sperm injection (ICSI).

The rationale and results of using epididymal and testicular spermatozoa with intracytoplasmic sperm injection (ICSI) for zoospermic patients are reviewed. A total of 128 consecutive ICSI/MESA cycles and a total of 120 consecutive ICSI/TESE cycles were performed up to December 1994. The two-pronuclei fertilization rate per intact oocyte (observed after the injection) was 58% and 60%, respectively, when epididymal and testicular spermatozoa were used. The embryo transfer rate was similar for the two procedures (91% after ICSI/MESA and 90% after ICSI/TESE). Fifty women became pregnant (positive HCG) when epididymal spermatozoa were used (39% per cycle and 40% per embryo transfer). These results are comparable to those obtained when ejaculated spermatozoa are used.

Cell Separation↗

Similarities and differences between the sperm quality index and sperm mobility index of broiler breeder semen.

The sperm quality index (SQI) and sperm mobility index (SMI) both predict sperm motility. Previous research was conducted comparing the SMI with the SQI; however, semen was diluted improperly for the SQI (40-fold). For an accurate comparison, semen must be diluted 10-fold for the SQI. Therefore, the overall objective of this study, utilizing 4 experiments, was to examine the relationship of the SQI with the SMI when: 1) active, heat-inactivated, and boiled sperm were incubated and analyzed over 60 min, 2) motile and immotile sperm were combined, 3) dead sperm (boiled or frozen) and live sperm were combined, and 4) sperm were rendered immotile by adding Zn. In experiment 1, the SQI was stable throughout incubation for active sperm and zero for heat-inactivated and boiled sperm. The SMI from active sperm steadily increased over incubation. However, the SMI from heat-inactivated sperm increased drastically resulting in values higher than active sperm after 35 min of incubation. The SMI from active sperm was higher than boiled sperm throughout incubation. For experiment 2, a cubic increase in the SQI occurred as active sperm increased from 0 to 100%. However, there was no difference in SMI readings until samples contained 80% active sperm. In experiment 3, for both boiled and frozen sperm, as the percentage of viable sperm increased, there was a logarithmic increase in the SQI. The SMI values were similar for 0 and 100% viable sperm when using boiled sperm, and all SMI readings were similar to 0% viable for frozen sperm. For experiment 4, both the SQI and SMI values from semen incubated with Zn were lower than that of saline. The SQI from sperm incubated in saline was higher than that of Zn throughout incubation, yet there were no differences in SMI values after 90 min of incubation. In conclusion, both the SQI and SMI of sperm decrease in response to Zn. However, it appears that immotile and dead sperm are capable of increasing SMI values but not SQI values.

Animals↗

Studies on sperm survival and motility in the presence of cytotoxic sperm antibodies.

The effect of cytotoxic sperm antibodies and native complement in the serum and secretions from 40 fertile and 93 infertile couples on in vitro sperm survival and motion characteristics was studied. Sperm survival in vitro was unaffected by sera from fertile and infertile subjects without cytotoxic sperm antibodies and from infertile men with antibodies to control but not to autologous sperm. Sperm survival was reduced (P less than .001) by sera from infertile men with antibodies to autologous sperm or to antologous and control sperm and from women with cytotoxic antibodies to sperm from both. Sera from fertile couples without sperm antibodies enhanced sperm swimming speed and motility index (P less than .0001). Sera from infertile women with or without cytotoxic sperm antibodies did not affect sperm motility. Sperm survival and motility were reduced by seminal plasma from infertile men with cytotoxic antibodies to autologous and/or control sperm. Seminal plasma from fertile men enhanced sperm survival. Cervical mucus from infertile women with antibodies to autoimmune husbands' sperm or to husbands' and control sperm inhibited sperm motion, whereas cervical mucus from infertile women without sperm antibodies and women with antibodies to control sperm failed to have any effect. It is concluded that cytotoxic sperm antibodies developed through exposure to sperm antigens in autoimmune infertile men decrease in vitro sperm survival and/or motility.

Antibodies↗

Use of Mammalian eggs for assessment of human sperm function: molecular and cellular analyses of fertilization by intracytoplasmic sperm injection.

PROBLEMS: Intracytoplasmic sperm injection (ICSI ) has been described as the 'cure' for male sterility because a single sperm can now be directly introduced into an egg with some chance of pregnancy. While ICSI has revolutionized the practice of assisted reproductive techniques (ART), there are few molecular and cellular studies about its safety and efficacy. Even by using ICSI, fertilization in humans succeeds only if the sperm effectively accomplishes a number of tasks including 'post-ICSI events' in fertilization. To assess the function of human sperm after ICSI, we used heterologous ICSI with human sperm into animal eggs. Egg activation, sperm decondensation and sperm centorosomal function were examined in sperm from fertile men and infertile patients. METHODS: Sperm from fertile men and infertile patients were injected into hamster, rabbit and bovine eggs by Piezo micromanipulator, and studied in decondensation of sperm nuclei, egg activation and microtubule organization. RESULTS: Decondensation human sperm head following ICSI into hamster eggs occurred initially form basal lesion, and apical portion of sperm nuclei which is surrounded by acrosome and perinuclear theca, still condensed in early pronuclear stage. Radial array of microtubules from sperm centrosome 'sperm aster' which is essential for pronuclear movement was observed in 30% rabbit eggs following ICSI with human sperm. By heterologous ICSI system with fertile human sperm and bovine eggs, 83.3% of eggs was activated and 60% eggs had sperm aster, indicating that bovine Piezo ICSI system is appropriate for assessing human sperm oocyte activation ability and human sperm centrosomal function. Oocyte activation and sperm centrosomal function were significantly low in sperm from men with globozoospermia and men with dysplasia of fibrous sheath. CONCLUSION: These assays indicate differences of the process of fertilization between in vitro fertilization and ICSI, and reflect the human sperm function especially for the 'post-ICSI events' in fertilization. More molecular and cellular analyses in fertilization by ICSI are needed for improvement of ART.

Acrosome↗

Sperm competition games: sperm selection by females.

We analyse a co-evolutionary sexual conflict game, in which males compete for fertilizations (sperm competition) and females operate sperm selection against unfavourable ejaculates (cryptic female choice). For simplicity, each female mates with two males per reproductive event, and the competing ejaculates are of two types, favourable (having high viability or success) or unfavourable (where progeny are less successful). Over evolutionary time, females can increase their level of sperm selection (measured as the proportion of unfavourable sperm eliminated) by paying a fecundity cost. Males can regulate sperm allocations depending on whether they will be favoured or disfavoured, but increasing sperm allocation reduces their mating rate. The resolution of this game depends on whether males are equal, or unequal. Males could be equal: each is favoured with probability, p, reflecting the proportion of females in the population that favour his ejaculate (the 'random-roles' model); different males are favoured by different sets of females. Alternatively, males could be unequal: given males are perceived consistently by all females as two distinct types, favoured and disfavoured, where p is now the frequency of the favoured male type in the population (the 'constant-types' model). In both cases, the evolutionarily stable strategy (ESS) is for females initially to increase sperm selection from zero as the viability of offspring from unfavourable ejaculates falls below that of favourable ejaculates. But in the random-roles model, sperm selection decreases again towards zero as the unfavourable ejaculates become disastrous (i.e. as their progeny viability decreases towards zero). This occurs because males avoid expenditure in unfavourable matings, to conserve sperm for matings in the favoured role where their offspring have high viability, thus allowing females to relax sperm selection. If sperm selection is costly to females, ESS sperm selection is high across a region of intermediate viabilities. If it is uncostly, there is no ESS in this region unless sperm limitation (i.e. some eggs fail to be fertilized because sperm numbers are too low) is included into the model. In the constant-types model, no relaxation of sperm selection occurs at very low viabilities of disfavoured male progeny. If sperm selection is sufficiently costly, ESS sperm selection increases as progeny viability decreases down towards zero; but if it is uncostly, there is no ESS at the lowest viabilities, and unlike the random-roles model, this cannot be stabilized by including sperm limitation. Sperm allocations in the ESS regions differ between the two models. With random roles, males always allocate more sperm in the favoured role. With constant types, the male type that is favoured allocates less sperm than the disfavoured type. These results suggests that empiricists studying cryptic female choice and sperm allocation patterns need to determine whether sperm selection is applied differently, or consistently, on given males by different females in the same population.

Animals↗

Disappearance of the PHA-E lectin binding site on the surface of ejaculated sperm and sperm capacitation in the dog.

Ejaculated semen and cross sections of the cauda epididymides collected from 3 normal dogs were smeared or stamped on glass slides, and the sperm on the slides were stained with 7 different FITC-lectins (Con A, DBA, GS-1, PHA-E, PSA, UEA-1, WGA) to examine the relation between sperm-binding glycoprotein derived from the canine prostate and sperm capacitation. The only lectin that stained the ejaculated sperm but not the cauda epididymal sperm was PHA-E. The sperm ejaculated by 5 other dogs were incubated for 4 hr in fluid flushed from the uterine horns or oviducts of estrous bitches, and then the percentages of actively motile sperm and hyperactivated sperm (HA-sperm) were determined. The percentages of PHA-E-labeled sperm and sperm labeled with fluoresceinated Ca indicator to assess the influx of Ca into the sperm were also evaluated. The mean percentages of actively motile sperm, HA-sperm, and Ca-labeled sperm after 4 hr of incubation in the uterine flush fluid and oviductal flush fluid were significantly higher than in control medium (P<0.05, 0.01), but the mean percentages of PHA-E-labeled sperm were lower (both P<0.01). The percentages of PHA-E-unlabeled sperm correlated with the percentages of both HA-sperm and Ca-labeled sperm (r(2)=0.787 and 0.812, respectively). The results indicate that loss of the glycoprotein secreted by the canine prostate on the sperm surface induces the influx of Ca into the sperm, and then hyperactivation of the sperm.

Acrosome Reaction↗

Evaluation of sperm fertilizing ability using the Sperm Quality Analyzer.

The Sperm Quality Analyzer is an inexpensive device which provides a quantitative estimation of sperm motility. To evaluate the fertilizing ability of human spermatozoa using a Sperm Quality Analyzer, correlations amongst the sperm motility index, the sperm penetration index (as assessed using the sperm penetration assay; SPA), and the fertilization rate in the treatment of standard IVF-ET were analysed retrospectively. The sperm motility index demonstrated a significant correlation with sperm concentration (p < 0.001), sperm motility (p < 0.001) and the motile sperm concentration (p < 0.001) in a total of 104 fresh semen samples from 81 men donating samples for IVF-ET. The sperm motility index also showed a significant correlation (p < 0.001) with the sperm penetration index in 60 patients, assessed using the SPA, before they were treated by standard IVF-ET. The correlation between the sperm motility index and the IVF-ET fertilization rate was higher than that between the sperm penetration index and the fertilization rate. The sperm motility index was classified into three categories: 'poor' (sperm motility index < 80), 'medium' (sperm motility index 81-160) and 'good' (sperm motility index > 160). The relationships between the IVF-ET fertilization rate and each category of the sperm motility index values were also evaluated. For the three categories in the sperm motility index, the fertilization rates (76.0%) of 60 samples judged as 'good' were significantly higher than those (44.2%) of 15 samples judged as 'medium' (p < 0.001) and those (34.7%) of 13 samples judged as 'poor' (p < 0.001). These results indicate that the Sperm Quality Analyzer provides a reliable estimation of the fertilizing ability of human spermatozoa.

Embryo Transfer↗

An evaluation of the mouse sperm morphology test and other sperm tests in nonhuman mammals. A report of the U.S. Environmental Protection Agency Gene-Tox Program.

The literature on the mouse sperm morphology test and on other sperm tests in nonhuman mammals was reviewed (a) to evaluate the relationship of these tests to chemically induced spermatogenic dysfunction, germ-cell mutagenicity, and carcinogenicity, and (b) to make an interspecies comparison to chemicals. A total of 71 papers were reviewed. The mouse sperm morphology test was used to assess the effects of 154 of the 182 chemical agents covered. 4 other murine sperm tests were also used: the induction of acrosomal abnormalities (4 agents), reduction in sperm counts, (6 agents), motility (5 agents), and F1 sperm morphology (7 agents)). In addition, sperm tests for the spermatogenic effects of 35 agents were done in 9 nonmurine mammalian species; these included analyses for sperm count, motility, and morphology, using a large variety of study designs. For the mouse sperm morphology test, 41 agents were judged by the reviewing committee to be positive inducers of sperm-head shape abnormalities, 103 were negative, and 10 were inconclusive. To evaluate the relationship between changes in sperm morphology and germ cell mutagenicity, the effects of 41 agents on mouse sperm shape were compared to available data from 3 different mammalian germ-cell mutational tests (specific locus, heritable translocation, and dominant lethal). The mouse sperm morphology test was found to be highly sensitive to germ-cell mutagens; 100% of the known mutagens were correctly identified as positives in the sperm morphology test. Data are insufficient at present to access the rate of false positives. Although it is biologically unclear why one might expect changes in sperm morphology to be related to carcinogenesis, we found that (a) a positive response in the mouse sperm morphology test is highly specific for carcinogenic potential (100% for the agents surveyed), and (b) overall, only 50% of carcinogens were positive in the test (i.e., sensitivity approximately equal to 50%). Since many carcinogens do not produce abnormally shaped sperm even at lethal doses, negative findings with the sperm test cannot be used to classify agents as noncarcinogens. We conclude that the mouse sperm morphology test has potential use for identifying chemicals that induce spermatogenic dysfunction and perhaps heritable mutations. Insufficient numbers of chemicals agents have been studied by the other sperm tests to permit similar comparisons. A comparison of 25 chemicals tested with sperm counts, motility, and morphology in at least 2 species (including man, mouse and 9 other mammals) demonstrated good agreement in response among species. With further study, interspecies comparisons of chemically induced sperm changes may be useful for predicting and evaluating human effects.

Animals↗

Studies on egg zona pellucida-binding molecule (ligand) of mouse sperm. I. Sperm maturation and zona-binding ability.

The epididymis has three major regions; the caput, corpus and cauda. Sperm were obtained from each region, and their binding ability to egg zona pellucida was assayed. In the case of intact sperm: cauda sperm bound in high number, corpus sperm bound at an intermediate level (an average of 30% of cauda sperm binding level), and caput sperm bound rarely (1% of cauda sperm binding level). In the case of sperm immobilized by pretreatment with LaCl3, when eggs and sperm were shaken in order to allow them to come into collision with each other, the caput and corpus sperm were able to bind to zona pellucida as well as the caudal sperm could. These results suggest that the difference in binding efficiency of the native caput and corpus sperm to bind to the zona pellucida was not due to a defect in a ligand molecule on the plasma membrane but rather to their lack of motility. When a sperm-egg binding assay was done in the presence of a binding inhibitor of caudal sperm, the binding of caudal sperm was significantly inhibited by fetuin or N-acetylgalactosamine, but the binding of caput and corpus sperm was only slightly inhibited by them. We prepared a plasma membrane fraction from each epididymal sperm, and solubilized it with sodium dodecyl sulfate (SDS). Each SDS-solubilizable fraction inhibited the binding of corresponding epididymal sperm to egg zona pellucida but didn't inhibit the binding of sperm from different regions of epididymis. These results suggested that a ligand molecule of caudal sperm was different from that of caput and corpus sperm.

Animals↗

Functional significance of the sperm head morphometric size and shape for determining freezability in iberian red deer (Cervus elaphus hispanicus) epididymal sperm samples.

In the present study, computer-automated sperm head morphometry of epididymal samples was used to determine if sperm head area and shape are useful measurements for separating "good" and "bad" Iberian red deer freezers. A microscope slide was prepared from single diluted sperm fresh samples collected from 38 mature stags. Slides were air-dried and stained with Hemacolor. The sperm head area and shape (length/width) for a minimum of 145 sperm heads were determined for each male by means of the Sperm-Class Analyser. The remainder of each sample was frozen. After thawing, sperm cryosurvival was judged in vitro by microscopic assessments of individual sperm motility and of plasma membrane and acrosome integrities. All sperm parameters evaluated at thawing were placed in a statistical database and a multivariate cluster analysis performed. Mean sperm parameters of the 2 clusters generated ("bad" and "good" freezers) were compared by ANOVA. Our results show that sperm quality at thawing for all sperm parameters evaluated was significantly higher (P < .01) for "good" freezers than for the "bad" ones (sperm motility index: 67.4 +/- 2.0 vs 57.1 +/- 2.8; NAR: 67.1 +/- 2.5 vs 54.5 +/- 3.5; viability: 68.8 +/- 2.0 vs 60.1 +/- 2.8; HOST: 71.3 +/- 2.2 vs 63.1 +/- 3.1). Additionally, differences (P < .01) in epididymal sperm head area and shape were found between "good" and "bad" freezers before freezing, with the smallest overall sperm head dimensions found in the "good" freezers group (area: 32.04 microm2 vs 34.42 microm2). Thus, the lower the sperm head area in the fresh samples, the greater the sperm cryoresistance. Our results show that the 2 groups of males also differ in sperm head shape in fresh samples (good: 1.96 vs poor: 1.72; P < .01). It is possible that sperm head area and shape influence total sperm volume, thus causing differences in heat exchange as well as in movements of water, ions, and cryoprotectants and, in turn, on sperm freezability.

Animals↗

Overexpressing sperm surface beta 1,4-galactosyltransferase in transgenic mice affects multiple aspects of sperm-egg interactions.

Sperm surface beta 1,4-galactosyltransferase (GalTase) mediates fertilization in mice by binding to specific O-linked oligosaccharide ligands on the egg coat glycoprotein ZP3. Before binding the egg, sperm GalTase is masked by epididymally derived glycosides that are shed from the sperm surface during capacitation. After binding the egg, sperm-bound oligosaccharides on ZP3 induce the acrosome reaction by receptor aggregation, presumably involving GalTase. In this study, we asked how increasing the levels of sperm surface GalTase would affect sperm-egg interactions using transgenic mice that overexpress GalTase under the control of a heterologous promoter. GalTase expression was elevated in many tissues in adult transgenic animals, including testis. Sperm from transgenic males had approximately six times the wild-type level of surface GalTase protein, which was localized appropriately on the sperm head as revealed by indirect immunofluorescence. As expected, sperm from transgenic mice bound more radiolabeled ZP3 than did wild-type sperm. However, sperm from transgenic animals were relatively unable to bind eggs, as compared to sperm from wild-type animals. The mechanistic basis for the reduced egg-binding ability of transgenic sperm was attributed to alterations in two GalTase-dependent events. First, transgenic sperm that overexpress surface GalTase bound more epididymal glycoside substrates than did sperm from wild-type mice, thus masking GalTase and preventing it from interacting with its zona pellucida ligand. Second, those sperm from transgenic mice that were able to bind the zona pellucida were hypersensitive to ZP3, such that they underwent precocious acrosome reactions and bound to eggs more tenuously than did wild-type sperm. These results demonstrate that sperm-egg binding requires an optimal, rather than maximal, level of surface GalTase expression, since increasing this level decreases sperm reproductive efficiency both before and after egg binding. Although sperm GalTase is required for fertilization by serving as a receptor for the egg zona pellucida, excess surface GalTase is counterproductive to successful sperm-egg binding.

Acrosome↗

Clinical application of sperm-oocyte interaction tests in in vitro fertilization--embryo transfer and intracytoplasmic sperm injection programs.

OBJECTIVE: To review the clinical value of sperm-oocyte interaction tests for the diagnosis and management of infertility by standard IVF or intracytoplasmic sperm injection (ICSI). DESIGN: Review of recent publications on relationships among sperm-oocyte interaction tests, sperm characteristics, and results of IVF and determination of frequency of defective sperm-oocyte interaction in infertile men. MAIN OUTCOME MEASURE(S): Fertilization rates with IVF, sperm characteristics, sperm-zona pellucida (ZP) binding, ZP-induced acrosome reaction (AR), and sperm-ZP penetration. RESULT(S): Sperm defects associated with low sperm-ZP binding or impaired ZP-induced AR and sperm-ZP penetration are the major causes of failure of fertilization when all or most oocytes from a couple do not fertilize in standard IVF. There is a high frequency of defective sperm-ZP interaction in men with oligozoospermia (<20 x 10(6)/mL) and severe teratozoospermia (strict normal sperm morphology < or =5%). Sperm morphology correlates with sperm-ZP binding, and sperm concentration correlates with ZP-induced AR in infertile men with sperm concentrations >20 x 10(6)/mL. Defective ZP-induced AR may cause infertility in up to 25% men with idiopathic infertility. These patients require ICSI despite the normal standard semen analyses. CONCLUSION(S): Sperm-oocyte interaction tests are useful for diagnosis of subtle sperm defects that cause infertility in men without severe abnormalities of semen analysis. Pre-IVF diagnosis of these sperm defects will assist in the clinical assignment of patients to treatment with either standard IVF or ICSI.

Embryo Transfer↗

A computerized postcoital test sperm motility: comparison with clinical postcoital test and correlations with sperm antibodies.

Sixty-five infertile women had a conventional postcoital test (PCT), a computerized postcoital test (cPCT), and sperm antibody testing. Twenty-four women had good cervical mucus and good PCT sperm motility (group 1), 23 had poor cervical mucus and poor PCT sperm motility (group 2), and 18 had good cervical mucus but poor PCT sperm motility (group 3). The percentage of motile sperm, mean linearity, and the motility index of sperm by cPCT also were decreased in groups 2 and 3 (p less than 0.001) in contrast to group 1. A reduced PCT sperm count was significantly associated with positive titers of antibodies to autologous sperm in the husbands' serum, whereas a reduced PCT motility correlated with high titers of cytotoxic antibodies to husbands' sperm in the wives' serum and cervical mucus. An increased percentage of vibratory sperm at PCT correlated with elevated titers of cytotoxic antibodies to husbands' sperm in the wives' serum and cervical mucus, and hemagglutinating (r = 0.44; p less than 0.001) and immunofluorescent IgA antibodies to husbands' sperm (r = 0.47; p less than 0.001) in the cervical mucus. Mean swimming speed of sperm by cPCT correlated inversely with cytotoxic and hemagglutinating antibody titers to husbands' sperm, and immunobead-binding IgM and immunofluorescent IgG, IgA, and IgM (r = 0.52; p less than 0.001) antibodies to sperm in the seminal plasma. Motility indices correlated inversely with cytotoxic antibody titers to husbands' sperm in the wives' serum, and hemagglutinating antibody titers to husbands' sperm in cervical mucus. The predictive values of PCT and cPCT for the presence of cytotoxic and immunofluorescent IgA antibodies to autoimmune husbands' sperm were 76% and 71%, respectively, in the serum and 85% and 75%, respectively, in the cervical mucus of the wives. The predictive value of PCT and cPCT for immunobead-binding and immunofluorescent IgM antibodies to sperm in the wives' serum was 71%. Computerized PCT measures more sperm characteristics than PCT, although it is in general agreement with PCT.

Antibody Formation↗

Influence of motility on the outcome of in vitro fertilization/intracytoplasmic sperm injection with fresh vs. frozen testicular sperm from men with obstructive azoospermia.

OBJECTIVE: To assess the efficacy of fresh vs. frozen testicular sperm on fertilization and pregnancy using intracytoplasmic sperm injection. DESIGN: Retrospective study. SETTING: Hospital-based infertility research laboratory. PATIENT(S): One hundred sixty patients with obstructive azoospermia undergoing testicular sperm extraction (TESE). INTERVENTION(S): Sections of seminiferous tubule were cryopreserved after TESE. Sperm motility and fertilizing ability were determined after thawing seminiferous tubule sections. MAIN OUTCOME MEASURES: Sperm motility and optimal fertilization and pregnancy rate. RESULT(S): Intracytoplasmic sperm injection was performed using fresh testicular sperm (fresh-sperm group; 84 cases) and thawed seminiferous tubules (thawed-sperm group; 177 cases). The overall fertilization rate was 65.4%, and the pregnancy rate was 34.0%. In the fresh-sperm group, the fertilization rate was 70.9%, and the pregnancy rate was 38.8%. In the thawed-sperm group, the fertilization rate was 62.7%, and the pregnancy rate was 21.7%. Fertilization rates were higher using fresh motile sperm vs. nonmotile sperm (77.0% vs. 29.3%). Pregnancy rates were higher using fresh motile sperm vs. nonmotile sperm (44.3% vs. 20.0%). The fertilization and pregnancy rates of motile vs. nonmotile sperm extracted from the thawed seminiferous tubule were 70.0% vs. 50.9% and 33.9% vs. 27.3%, respectively. Motile spermatozoa could be obtained several hours after thawing in most of the cases. CONCLUSION(S): Optimal fertilization and pregnancy rates were achieved using fresh vs. frozen sperm obtained using TESE when motile sperm were identified. Motile spermatozoa provided superior results to nonmotile sperm and are necessary for optimal fertilization and pregnancy outcomes.

Adult↗

Experimental evidence for the evolution of numerous, tiny sperm via sperm competition.

Sperm competition, when sperm from different males compete to fertilize a female's ova, is a widespread and fundamental force in the evolution of animal reproduction. The earliest prediction of sperm competition theory was that sperm competition selected for the evolution of numerous, tiny sperm, and that this force maintained anisogamy. Here, we empirically test this prediction directly by using selective breeding to generate controlled and independent variance in sperm size and number traits in the cricket Gryllus bimaculatus. We find that sperm size and number are male specific and vary independently and significantly. We can therefore noninvasively screen individuals and then run sperm competition experiments between males that differ specifically in sperm size and number traits. Paternity success across 77 two-male sperm competitions (each running over 30-day oviposition periods) shows that males producing both relatively small sperm and relatively numerous sperm win competitions for fertilization. Decreased sperm size and increased sperm number both independently predicted sperm precedence. Our findings provide direct experimental support for the theory that sperm competition selects for maximal numbers of miniaturized sperm. However, our study does not explain why G. bimaculatus sperm length persists naturally at approximately 1 mm; we discuss possibilities for this sperm size maintenance.

Animals↗