A test of the human sperm acrosome reaction following ionophore challenge. Relationship to fertility and other seminal parameters.
TL;DR: The test was shown to have a predictive value for fertility comparable to that of the hamster ovum sperm penetration assay and to be a simple and cost-effective addition to existing semenology.
Abstract: Acrosome reaction capacity was tested on semen samples from 53 fertile and 26 subfertile men. Preparations were divided into two aliquots after 3 or 24 hours of culture. One aliquot received 10 mumol/L calcium ionophore A23187 in dimethyl sulfoxide (DMSO) and the other received DMSO alone. Acrosome reactions were scored on ethanol-permeabilized smears using fluorescein isothiocyanate (FITC)-conjugated Pisum sativum lectin. The following factors were analyzed: the spontaneous reaction rates (control); induced reaction rates (ionophore-challenged); and the difference between the two, being the proportion of spermatozoa in the population capable of reacting in response to calcium influx (acrosome reaction to ionophore challenge [ARIC]). While spontaneous reactions bore no relation to fertility, induced reactions and ARICs were significantly reduced or absent in subfertile men, indicating acrosomal dysfunction as a likely cause of fertilization failure. The test was shown to have a predictive value for fertility comparable to that of the hamster ovum sperm penetration assay and to be a simple and cost-effective addition to existing semenology.
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TL;DR: Dynamics in adhesive and fusion properties, molecular composition and architecture of the sperm plasma membrane, as well as membrane derived signalling are reviewed.
580 citations
TL;DR: This work has confirmed that spermatozoa were the first cell type in which the cellular generation of reactive oxygen was demonstrated and the importance of oxidative damage in the male germ line to the origins of male infertility, early pregnancy loss and childhood disease, deserves attention.
Abstract: Spermatozoa were the first cell type in which the cellular generation of reactive oxygen was demonstrated. This activity has now been confirmed in spermatozoa from all mammalian species examined including the rat, mouse, rabbit, horse, bull and human being. Under physiological circumstances, cellular redox activity is thought to drive the cAMP-mediated, tyrosine phosphorylation events associated with sperm capacitation. In addition to this biological role, human spermatozoa also appear to suffer from oxidative stress, with impacts on the normality of their function and the integrity of their nuclear and mitochondrial DNA. Recent studies have helped to clarify the molecular basis for the intense redox activity observed in defective human spermatozoa, the nature of the subcellular structures responsible for this activity and possible mechanisms by which oxidative stress impacts on these cells. Given the importance of oxidative damage in the male germ line to the origins of male infertility, early pregnancy loss and childhood disease, this area of sperm biochemistry deserves attention from all those interested in improved methods for the diagnosis, management and prevention of male-mediated reproductive failure.
299 citations
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...In addition, deficiencies in the ability of spermatozoa to acrosome react has also been recorded in infertile men, using A23187 (calcium ionophore) or the native zona pellucida as the activating stimulus (Aitken et al. 1984, 1994; Cummins et al. 1991; Liu and Baker 1994)....
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295 citations
TL;DR: A range of in vitro tests have been developed to monitor various aspects of sperm function including their potential for movement, cervical mucus penetration, capacitation, zona recognition, the acrosome reaction and sperm-oocyte fusion and such functional assays have been found to predict the fertilizing capacity of human spermatozoa in vitro and in vivo with some accuracy.
Abstract: Traditionally, the diagnosis of male infertility has depended upon a descriptive evaluation of human semen with emphasis on the number of spermatozoa that are present in the ejaculate, their motility and their morphology. The fundamental tenet underlying this approach is that male fertility can be defined by reference to a threshold concentration of motile, morphologically normal spermatozoa that must be exceeded in order to achieve conception. Many independent studies have demonstrated that this fundamental concept is flawed and, in reality, it is not so much the absolute number of spermatozoa that determines fertility, but their functional competence. In the light of this conclusion, a range of in vitro tests have been developed to monitor various aspects of sperm function including their potential for movement, cervical mucus penetration, capacitation, zona recognition, the acrosome reaction and sperm-oocyte fusion. Such functional assays have been found to predict the fertilizing capacity of human spermatozoa in vitro and in vivo with some accuracy. Recent developments in this field include the introduction of tests to assess the degree to which human spermatozoa have suffered oxidative stress as well as the integrity of their nuclear and mitochondrial DNA. Such assessments not only yield information on the fertilizing capacity of human spermatozoa but also their ability to support normal embryonic development.
286 citations
TL;DR: A number of laboratory tests have been developed to determine properties of sperm function but few have been adopted into routine clinical use and international collaborations should be initiated to develop clinically relevant molecular and functional tests.
Abstract: Traditionally, the diagnosis of male infertility has relied upon microscopic assessment and biochemical assays to determine human semen quality. The conventional parameters given most importance have been the concentration, motility, and morphology of sperm in the ejaculate. Most laboratories also include 'sperm suitability' tests where the subpopulations of sperm more likely to finish the marathon journey to the oocyte are separated by density centrifugation. These tests are essential to provide the fundamental information on which clinicians base their initial diagnosis. However, none of these parameters addresses sperm function and their clinical value in predicting fertility is questionable. The advent of intracytoplasmic sperm injection (ICSI) has further reduced the significance and perceived need for sperm quality tests since ICSI requires only one sperm, not subject to classic, or indeed any, tests for the procedure to be successful. Over the past decade, a number of laboratory tests have been developed to determine properties of sperm function. These include quantitative sperm motion parameters, capacitation, basal and induced acrosome reactions, sperm-zona pellucida interactions and nuclear and mitochondrial sperm DNA but few have been adopted into routine clinical use. International collaborations should be initiated to develop clinically relevant molecular and functional tests with agreed protocols and clinical thresholds as a matter of urgency.
274 citations
Cites background from "A test of the human sperm acrosome ..."
...1984) but acrosome reactions induced by the ionophore A23187 (ARIC) test is a good predictor of the sperm’s fertilizing potential and is markedly reduced in infertile men (Cummins et al. 1991)....
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...The basal acrosome reaction has limited usefulness (Plachot et al. 1984) but acrosome reactions induced by the ionophore A23187 (ARIC) test is a good predictor of the sperm’s fertilizing potential and is markedly reduced in infertile men (Cummins et al. 1991)....
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References
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TL;DR: The results suggest that zona-free hamster ova can be substituted for human ova in the preliminary assessment of the fertilizing capacity of human spermatozoa.
Abstract: The zona-free hamster ovum was evaluated as a substitute for human o va in the assessment of the fertilizing capacity of human spermatozoa. Zona-intact ova completely resisted sperm penetration. Using nonpreincu bated spermatozoa sperm penetration of zona-free ova began 4-5 hours after insemination. However when spermatozoa were preincubated in a modified Krebs-Ringer solution for 4 hours sperm penetration began within 1 hour. There is some evidence that this is associated with the completion of sperm capacitation and the acrosome reaction. The results suggest that zona-free hamster ova can be substituted for human ova in the preliminary assessment of the fertilizing capacity of human spermatozoa.
871 citations
01 Jan 1981
TL;DR: This chapter will discuss how mammalian spermatozoa prepare themselves for fertilization and how the spermatozosa and eggs interact during fertilization.
Abstract: The spermatozoa of most invertebrates (e.g., sea urchins) and nonmammalian vertebrates (e.g., fishes and amphibians) have full capacity to fertilize eggs upon leaving the testis. Testicular spermatozoa of mammals, on the other hand, do not possess the ability to do so. Their fertilizing capacity develops as they pass through the epididymis (Young, 1931; Nishikawa and Waide, 1952; Blandau and Rumery, 1964; Bedford, 1966; Orgebin-Crist, 1967). This process, apparently “unique” to mammals, is referred to as the epididymal maturation of spermatozoa. Even after their maturation, however, spermatozoa require an additional phase of maturation or capacitation within the female genital tract before they are able to fertilize eggs (Austin, 1951, 1952; Chang, 1951a). Thus, epididymal maturation and capacitation are two extra steps that mammaliam spermatozoa must take before they can effect fertilization. In this chapter, I will discuss how mammalian spermatozoa prepare themselves for fertilization and how the spermatozoa and eggs interact during fertilization. The process and mechanisms of sperm transport in the female genital tract will not be dealt with extensively here. Readers are referred to Bishop (1961, 1969), Blandau (1969), Bedford (1970b, 1972b), Thibault (1972, 1973a), Zamboni (1972), Blandau and Gaddum-Rosse (1974), Hafez and Thibault (1975), Overstreet and Katz (1977), Overstreet and Cooper (1978, 1979b), Overstreet et al. (1978), Shalgi and Kraicer(1978), Cooper et al. (1979) and Hunter (1975, 1980). The rejection or elimination of extra spermatozoa by the fertilized egg, one of the most fascinating events in fertilization, will not be discussed here. Instead, readers are referred to the chapter by Dr. Wolf in this volume. The physiology of egg activation has been described and discussed to some extent by Gwatkin (1977) and Yanagimachi (1978a). There are numerous reviews dealing with general aspects of mammalian fertilization. The following are recommended to aid in grasping the outline of mammalian fertilization: Austin and Bishop (1957), Austin and Walton (1960), Austin (1961, 1968), Blandau (1961), Piko (1969), Thibault (1969), Bedford (1970a,b, 1972b), Gwatkin (1976, 1977), Yanagimachi (1977, 1978a), Bedford and Cooper (1978) and Hunter (1980).
773 citations
TL;DR: Two methods for detecting acrosome reactions of human sperm at the light microscopic level are described, rapid, give similar results, and detect an increase in acrosomes reactions following exposure to the ionophore A23187.
Abstract: We describe two methods for detecting acrosome reactions of human sperm at the light microscopic level. The techniques include the use of a supravital stain to detect dead sperm in order to differentiate between “physiological” and “degenerative” acrosome reactions. Sperm are incubated with the supravital stain Hoechst 33258 (a fluorescent DNA-binding dye with limited membrane permeability), washed, suspended in 95% ethanol for fixation and permeabilization, and dried onto slides. The sperm are then labeled either by indirect immunofluorescence using rabbit anti-human sperm antiserum or with fluoresceinated Pisum sativum agglutinin (PSA). Both probes intensely label the acrosomal region of acrosome-intact sperm. Electron microscopy revealed the major site of PSA binding to be the acrosomal contents. Acrosome-reacted sperm have diminished acrosomal labeling by both probes; sperm with nuclei labeled by Hoechst stain are considered nonviable, and are excluded from the assay. Both assays are rapid, give similar results, and detect an increase in acrosome reactions following exposure to the ionophore A23187.
593 citations
TL;DR: The use of hamster eggs to activate human sperm to the point where their chromosomes can be studied directly is reported here and some claims have now been retracted.
Abstract: ALL available information on the chromosome constitution of human gametes is speculative, having been obtained by inference from the chromosome constitution of conceptuses that survive sufficiently long to produce a clinically recognisable pregnancy. A minimum of 10% of all recognised human conceptions are chromosomally abnormal, and it has been estimated that 1–2% are the result of fertilisation by a spermatozoon with a chromosome abnormality1. Cytological evaluation of the chromosome constitution of human spermatozoa has been restricted to the staining of fixed smears of whole sperm2–13. Certain chromosome regions with peculiar staining properties, such as the long arm of the Y chromosome and the heterochromatic region of chromosome 9, are presumed to be represented in appropriately stained sperm nuclei by differentially staining spots. By counting the number of these spots per nucleus, the frequency of aneuploidy in the sperm of normal males has been estimated to be around 40% (refs 5, 9–11). The precision of the data obtained from stained whole sperm is dubious, because several factors must be taken into consideration when blobs are counted in sperm head nuclei, all of which could contribute to biased estimates of nondisjunction7,8,12. For this reason, some claims have now been retracted12,13. To investigate the true contribution of male gametes to the production of chromosomally abnormal conceptuses and the factors influencing the production and survival of chromosomally abnormal sperm, it is necessary to analyse the sperm chromosomes directly. However, after meiotic metaphase II sperm chromosomes do not reappear until the male and female pronuclei of the fertilised egg prepare for the first cleavage division. We report here the use of hamster eggs to activate human sperm to the point where their chromosomes can be studied directly.
383 citations
257 citations