The tonicity of murine epididymal spermatozoa and their permeability towards common cryoprotectants and epididymal osmolytes

Cooper, Trevor G.; Barfield, Jennifer P.; Yeung, Ching‐Hei

doi:10.1530/rep-07-0573

Cited by 18 publications

(16 citation statements)

References 40 publications

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“…However, recent studies examining the osmolality of cauda epididymal fluid found that murine spermatozoa are actually stored in a hyperosmotic milieu in cauda epididymides ranging from 375 to 500 mmol/kg (Yeung et al 1999, Cooper et al 2008. Even after ejaculation, spermatozoa are still at a slightly hyperosmotic condition in the female reproductive tract (uterine fluid is 330 mmol/kg; Yeung et al 2000).…”

Section: Introductionmentioning

confidence: 99%

Osmotic characteristics and fertility of murine spermatozoa collected in different solutions

Men²,

Benson³

et al. 2009

Reproduction

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Osmotic stress is an important factor that can result in cell damage during cryopreservation. Before ejaculation or collection for cryopreservation, murine spermatozoa are stored in epididymal fluid, a physiologically hyperosmotic environment (w415 mmol/kg). The objectives of this study were to determine the osmotic tolerance limits of sperm motion parameters of ICR and C57BL/6 mouse spermatozoa collected in isosmotic (290 mmol/kg) and hyperosmotic (415 mmol/kg) media, and the effect of the osmolality of sperm collection media on sperm fertility after cryopreservation. Our results indicate that murine spermatozoa collected in media with different osmolalities (290 and 415 mmol/kg Dulbecco's phosphate buffered saline (DPBS)) appeared to have different osmotic tolerances for the maintenance of sperm motility and other motion parameters in both mouse strains. The hypo-and hyperosmotic treatments decreased motility and affected other motion parameters of spermatozoa collected in 290 mmol/kg DPBS. The extent of the change of motion parameters after treatments corresponded with the levels of osmotic stress. However, for spermatozoa collected in 415 mmol/kg DPBS, exposure to 290 mmol/kg DPBS tended to increase sperm motility and the quality of their motion parameters. The osmolality of sperm collection medium can affect murine sperm fertility. Spermatozoa collected in 415 mmol/kg medium showed higher fertility compared with spermatozoa collected in 290 mmol/kg as assessed by IVF. Results characterizing murine sperm osmotic tolerance collected in media with different osmolalities from different strains and the effect of collection media osmolality on sperm fertility after cryopreservation will be useful in designing cryopreservation protocols.

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Section: Introductionmentioning

confidence: 99%

Osmotic characteristics and fertility of murine spermatozoa collected in different solutions

Men²,

Benson³

et al. 2009

Reproduction

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“…In this experimental design (termed the initial time-course protocol), spermatozoa were pre-incubated in a medium with the mean osmolality of epididymal fluid, i.e. close to isotonic conditions (Cooper et al 2008), so that osmotic challenges would be minimised during preincubation with the putative inhibitors without quinine. Thereafter, they were subjected to a physiological osmotic challenge in the drug in the absence or presence of quinine.…”

Section: Discussionmentioning

confidence: 99%

“…In the second protocol (initial time-course), the tubule contents were transferred to an albumin (4 mg/ml)-containing BWW medium with osmolality raised with NaCl to 430 mmol/kg (BWW 430 ; similar to that of epididymal fluid (Yeung et al 1999) and close to isotonic with cauda epididymidal spermatozoa (Cooper et al 2008)) for preincubation at 37 8C in the presence of water transport inhibitors but not quinine. After 10 min, the sample was transferred to BWW 330 containing 6 mg/ml PI as well as the inhibitor with or Water channels in murine spermatozoa without 800 mmol/l quinine and read immediately and continuously for 5 min in the flow cytometer.…”

Section: Animal Experimentsmentioning

confidence: 99%

Channels for water efflux and influx involved in volume regulation of murine spermatozoa

Callies¹,

Cooper²,

Yeung³

2008

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The nature of the membrane channels mediating water transport in murine spermatozoa adjusting to anisotonic conditions was investigated. The volume of spermatozoa subjected to physiologically relevant hypotonic conditions either simultaneously, or after isotonic pre-incubation, with putative water transport inhibitors was monitored. Experiments in which quinine prevented osmolyte efflux, and thus regulatory volume decrease (RVD), revealed whether water influx or efflux was being inhibited. There was no evidence that sodium-dependent solute transporters or facilitative glucose transporters were involved in water transport during RVD of murine spermatozoa since phloretin, cytochalasin B and phloridzin had no effect on volume regulation. However, there was evidence that Hg 2C -and Ag C -sensitive channels were involved in water transport and the possibility that they include aquaporin 8 is discussed. Toxic effects of these heavy metals were ruled out by evidence that mitochondrial poisons had no such effect on volume regulation.

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“…In mice, seminal vesicle fluid is iso-osmolal with blood, 12 that is, hypotonic with respect to epididymal contents. 34 This means that cauda epididymidal spermatozoa are suddenly confronted at ejaculation with a drastic decrease in osmolality, initially in the accessory gland fluids, which expel them from the male tract, and later in the hypotonic female tract fluid. This would lead to an influx of water and cell swelling if this process were not countered by the regulatory volume decrease (RVD).…”

Section: Sperm Volume Regulation: the Fluid Environmentmentioning

confidence: 99%

The epididymis, cytoplasmic droplets and male fertility

Cooper¹

2010

Asian J Androl

148

130

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The potential of spermatozoa to become motile during post-testicular maturation, and the relationship between the cytoplasmic droplet and fertilizing capacity are reviewed. Post-testicular maturation of spermatozoa involves the autonomous induction of motility, which can occur in vivo in testes with occluded excurrent ducts and in vitro in testicular explants, and artefactual changes in morphology that appear to occur in the testis in vitro. Both modifications may reflect time-dependent oxidation of disulphide bonds of head and tail proteins. Regulatory volume decrease (RVD), which counters sperm swelling at ejaculation, is discussed in relation to loss of cytoplasmic droplets and consequences for fertility. It is postulated that: (i) fertile males possess spermatozoa with sufficient osmolytes to drive RVD at ejaculation, permitting the droplet to round up and pinch off without membrane rupture; and (ii) infertile males possess spermatozoa with insufficient osmolytes so that RVD is inadequate, the droplet swells and the resulting flagellar angulation prevents droplet loss. Droplet retention at ejaculation is a harbinger of infertility caused by failure of the spermatozoon to negotiate the uterotubal junction or mucous and reach the egg. In this hypothesis, the epididymis regulates fertility indirectly by the extent of osmolyte provision to spermatozoa, which influences RVD and therefore droplet loss. Man is an exception, because ejaculated human spermatozoa retain their droplets. This may reflect their short midpiece, approximating head length, permitting a swollen droplet to extend along the entire midpiece; this not only obviates droplet migration and flagellar angulation but also hampers droplet loss. Keywords: epididymis; fertility; infertility; sperm maturation INTRODUCTION During passage of mammalian spermatozoa through the epididymal duct, the functionally incompetent germ cell produced by the testis is matured and stored. In this time (around 1-2 weeks in most species), the spermatozoon undergoes many changes that prepare it for achieving the diverse tasks required of it. At ejaculation, when it is rapidly expelled from the epididymis through the vas deferens to the world outside, the spermatozoon undergoes another phase in which it encounters fluids of the male accessory sex glands, escapes from them in the vagina, cervix or uterus, depending on species, and interacts with the oviductal lining before fertilizing the female gamete. Many mechanisms control the timing of these events, all of which require adequate responses by the fertilizing spermatozoon, and several of these have their origins in the epididymis. This paper addresses a few controversial, novel or still unanswered topics related to the maturation, volume regulation and morphology of spermatozoa.

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The tonicity of murine epididymal spermatozoa and their permeability towards common cryoprotectants and epididymal osmolytes

Cited by 18 publications

References 40 publications

Osmotic characteristics and fertility of murine spermatozoa collected in different solutions

Osmotic characteristics and fertility of murine spermatozoa collected in different solutions

Channels for water efflux and influx involved in volume regulation of murine spermatozoa

The epididymis, cytoplasmic droplets and male fertility

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