How long is sperm in epididymis

A sperm can live for up to 5 days in the woman's vagina. However, if it is released into the open, it cannot live for more than a few minutes. If sperm is not ejaculated, it stays in the man's body for about 74 days. After this, the sperm cells die and are reabsorbed by the body. If a couple is trying to get pregnant, the man should avoid ejaculating for a few days before sexual intercourse. This increases the concentration of sperm in the semen and maximizes sperm count and the chances of impregnating his partner.

How long the sperm lives inside the testicles? Sperm Life Cycle When a boy is born, the seminiferous tubules in the testes contain simple round cells. How Does this Affect Fertility? What is a Hypospermia? Know More. How is blockage in the tubes that transport sperms treated? How is Hypospermia Diagnosed? How does mumps affect male fertility? How much does it cost to do a semen analysis?

How can we improve sperm motility? What can cause a low sperm count? What Is a Hypospadias? What is a normal sperm count? What Causes the Testosterone Levels to Drop? What is Estrogen in Men? What is Leukocytospermia? What is Male Chlamydia? This poses the question of how these successes obtained following surgical reanastomosis of the male tract or sperm aspiration, and ART procedures to overcome pathologies affecting male fertility are informative with regard to epididymal physiology in men.

Epididymal sperm maturation involves both modifications to flagellar beating and acquisition of properties necessary to efficiently encounter the egg's vestments, especially the zona pellucida an acellular glycoprotein coat surrounding the egg.

Work on animal models has taught us that these physiological changes involve sperm surface modifications that occur during epididymal transit. These include: an increase in total negative surface charge Moore and Akhondi, ; modifications to lectin-binding properties Hermo et al. All of these changes involve complex interactions between epididymal secretions and male gametes: modifications that are essential for the acquisition of sperm fertilizing ability Haidl et al.

Some sperm parameter modifications occurring during epididymal transit have been described in humans Blaquier et al.

Sperm chromatin condensation increases during epididymal transit of the human spermatozoa, in addition to forward motility Haidl et al. There is also an increased capacity of zona-free hamster oocyte penetration by transiting spermatozoa Hinrichsen and Blaquier, ; Moore and Akhondi, Information on biochemical modifications undergone by the male gamete in the human male reproductive tract is scarce.

Tezon et al. Metabolic labelling revealed that proximal segments are the more active in protein synthesis. Androgens have a stimulatory effect on the synthesis of only a few of these proteins Tezon et al. Evidence is presented suggesting the association of androgen-dependent secreted proteins with epididymal spermatozoa; these proteins remain associated with spermatozoa after ejaculation Tezon et al. The use of interfering antibodies allowed the identification of epididymal-originating proteins associated with ejaculated human spermatozoa; P34H and FLB1 play specific roles in fertilization such as zona pellucida binding Boue et al.

The origin and functions of P34H in particular have been well documented. This protein is synthesized and secreted by the human corpus epididymis where it is added to the sperm surface covering the acrosome Boue et al. This protein is a dicarbonyl reductase playing multiple functions according to the cell type synthesizing this protein, the sub-compartment localization and the differentiation status Lee et al.

Complementary DNA sequencing revealed the absence of a signal peptide Legare et al. As the protein is GPI anchored to the sperm surface, it has been hypothesized that epididymal principal cells use the apocrine pathway to secrete P34H into the intraluminal compartment. Specific anti-P34H antibodies inhibit sperm—zona pellucida binding in vitro without affecting other fertilization steps Boue et al. Furthermore, the absence of P34H is associated with cases of male infertility Boue and Sullivan, Moskovtsev et al.

Thus, the epididymal protein P34H is added to the sperm surface during its transit along the human epididymis and plays a major role in sperm physiology Sullivan, ; Sullivan, ; Desrosiers, et al. It also supports the concept that epididymal dysfunction can be involved in the pathophysiology of male infertility.

There is increasing evidence that epididymal principal cells secrete extracellular microvesicles named epididymosomes. Described in different species, epididymosomes are involved in the trafficking of selected subsets of epididymal proteins to spermatozoa for review: Sullivan, The proteome of epididymosomes collected during vasectomy procedures is characterized by numerous proteins with potential roles in sperm physiological functions Thimon et al.

This provides indirect evidence supporting the key role of the epididymis in human reproductive physiology. There is sufficient physiological and biochemical evidence to support the role of the epididymis in human sperm maturation, i. The challenge remains as to how this evidence can be reconciled with clinical data obtained from men undergoing reanastomosis of the vas deferens at different points along the excurrent duct.

During the early days of epididymal research, two possibilities were considered to explain sperm maturation: the epididymis was actively involved in this process or sperm maturation was a post-testicular time-related event. To distinguish between these two possibilities, rabbit epididymis was ligated upstream of the site of apparition of fertilizing spermatozoa and male gametes were collected at different time points upstream of the ligation site.

At the initial time points, the collected spermatozoa were dysfunctional or immature. After a certain period of time, a longer period than the time required to complete the epididymal journey, functional spermatozoa appeared upstream of the ligation. From these experiments, it was concluded that under obstruction, the proximal segment of the epididymis is able to differentiate or to reprogram itself to mimic the functions of the downstream epididymal segments Bedford, ; Bedford et al.

If this is the case, it would explain the pregnancy outcome in men having undergone reanastomosis of the vas deferens along the epididymis, a surgery performed to overcome excurrent duct ligation, obstruction or agenesis Legare et al. Vasectomy consists of ligation of the scrotal portion of the vas deferens Art and Nangia, This contraceptive procedure performed on a large scale is an interesting model with which to understand the consequences of obstruction on epididymal physiology in men Sullivan et al.

A very limited number of reports describe the consequences of vasectomy on the human epididymis because of the scarcity of specimens. Only a few histological studies have been published, which mainly describe the formation of granuloma and epididymal distension after vasectomy in men Bedford, ; McDonald, At the morphological and histological levels, responses to vasectomy vary from one species to another, questioning the relevance of animal models for studying post-vasectomy sequelae Bedford, ; McDonald, The immune response against spermatozoa following vasectomy has been exhaustively studied using different laboratory animals including non-human primates Alexander, ; Clarkson and Alexander, The knowledge that vasectomy can result in anti-sperm antibody production in men raised serious concerns regarding the safety of this procedure.

Since then, many epidemiological studies have investigated possible correlations between vasectomy and an increase in the incidence of different pathologies including atherosclerosis Clarkson and Alexander, and prostate cancer Khan and Partin, It is now generally believed that no such correlation exists Nienhuis et al. This emphasizes the fact that results concerning the consequences of vasectomy obtained using animal models, including primates, must be extrapolated to men with caution.

The effects of vasectomy on different epididymal physiological parameters, such as trans-epithelial water reabsorption Hohlbrugger and Pfaller, , intratubular hydrostatic pressure Johnson and Howards, and fluid movement in the epididymis Turner et al. Whereas gene expression patterns and intraluminal protein compositions along the epididymis have been exhaustively studied during the last two decades, the consequences of vasectomy on these biochemical parameters are poorly documented.

Vasectomy selectively affects expression of a cysteine-rich secretory protein in the rat caput epididymidis Turner et al. At least in the rat, the consequences of vasectomy on epididymal protein secretion are irreversible following vasovasostomy Turner et al.

Many studies Bedford, ; Bedford, ; McDonald, , including some of our own Legare et al. After vasectomy, the gene encoding P34H is not expressed by the corpus epididymis as in normal men, but is expressed instead in the caput segment of the human epididymis Legare et al.

Consequently, ejaculated spermatozoa of some vasovasostomized men lack this epididymal protein. In normal men the thickness of the epididymal epithelium varies from one segment to the other; the maximum thickness being found in the distal caput—corpus. After vasectomy, the maximum thickness is reached in the proximal caput epididymidis. In vasectomized men, the thickness of the epithelium in the proximal caput is similar to that which is characteristic of the corpus epididymidis in normal men.

In fact, P34H follows the same shift in expression as the shift in maximal epithelium thickness observed in the epididymis of vasectomized men Legare et al. These observations on the consequences of vasectomy on human epididymis correlate with the changes in distribution of fertile sperm along the epididymis after ligation.

Thus, it appears that in animal models, as in humans, the pattern of differentiation observed along the epididymis is modified after obstruction ligation or vasectomy. This could be the underlying physiological mechanism explaining the recovery of fertility in men presenting with surgical epididymo-vasostomy.

Transcriptomic studies reveal that vasectomy affects the pattern of gene expression along the length of the human epididymis Thimon et al.

The distribution pattern of miRNAs along the excurrent duct is also affected by vasectomy Belleannee et al. Other observations support the hypothesis that in some vasovasostomized men, spermatozoa are unable to undergo some of the necessary steps leading to fertilization as a result of epididymal defects occurring after vasectomy; defects that are irreversible following vasovasostomy Legare et al. This may explain the discrepancies between surgical success of vasectomy reversal and pregnancy outcome.

Effect of vasectomy on the human epididymis transcriptome. Heat map of hierarchical clustering of probe sets corresponding to known mRNAs of caput, corpus and cauda epididymidis of normal and vasectomized Vasect. Each cell in the matrix represents the expression level of each mRNA affected by vasectomy. The blue-red scale indicates the intensity level of expression. Adapted from Thimon et al. The pseudocolor representation of FC is shown such that red indicates high and blue represents low changes.

In rats, the epididymis reaches 6 m in length and can be as long as 50 m in large domestic animals. In humans, the epididymal tubule measures a modest 5 m. Sperm transit along the human epididymis takes 2—4 days Bedford, , which is quite rapid when compared with the to day journey in laboratory and domestic animals.

As with the other segments, the cauda epididymis is poorly developed in humans Johnson and Varner, This correlates with the very limited sperm reservoir capacity in our species. After performing semen analyses on successive ejaculates from healthy young men, Bedford determined that the reservoir capacity in humans does not exceed the number of male gametes necessary to produce two to three normal semen samples.

Again, human epididymal function is far from being as efficient as in other mammalian species Amann and Howards, In humans, the sperm reservoir capacity of the cauda epididymidis is comparable to that found in experimental abdominal epididymo-cryptorchidism in the rat. This observation makes sense with knowledge of the effect of temperature increase on epididymal sperm reservoir function Amann, ; Bedford, Speculation exists over whether the poorly differentiated cauda segment in humans is due to a newly acquired adaptation to lifestyle affecting scrotal temperature Bedford, or to a reproductive strategy in our species with little inter-individual sperm competition pressure.

Sperm production by the human testis is in fact notoriously very low when compared with other mammalian species Amann and Howards, ; Johnson and Varner, ; Amann, This could help to explain the poor sperm reservoir capacity in our species. The fact remains that the distal portion of the epididymis is poorly developed in men Johnson, In rodents, the proximal epididymis initial segment and caput is the most responsive segment to intraluminal factors proposed to control downstream gene expression.

Consequently, the caput epididymis is very active in gene expression characterized by a segment-specific transcriptome signature. In these species, septa define different compartments along the epididymis.

It has been hypothesized that these structures are also involved in the regulation of gene expression. There is no doubt that the anatomy of the human epididymis is peculiar when considering the absence of an initial segment, the proximal caput formed by efferent ducts and the presence of poorly defined and incomplete septa that do not clearly demark epididymal compartments.

These observations raise questions concerning the functional significance of this organ in humans. The rapid sperm transit, the relatively small diameter of the epididymal tubule and the poorly differentiated cauda segment also give the impression that the epididymis may not be as important for sperm maturation in human as shown in laboratory animals. In contrast, transcriptomic and proteomic studies teach us that the pattern of gene expression varies along the human epididymis with the caput segment having the highest transcriptomic activity.

Together with the available information concerning epididymal physiology in normal men, these observations support the concept of epididymal sperm maturation in humans. Almost all our knowledge of epididymal sperm parameters is based on sperm cells collected along the male tract in cases of epididymis obstruction and agenesis.

If spermatozoa present in the epididymis under vasectomy are comparable to those collected in obstructed organs, conclusions on human epididymal function may be distorted. It should be borne in mind that spermatozoa that have undergone only a partial epididymal transit have limited fertilizing ability, and that ART, such as ICSI, have to be applied to generate zygotes with these male gametes.

The rapid evolution of reproductive technologies applied to overcome male infertility has jeopardized efforts to understand epididymal physiology during the previous two decades. The limited number of studies exploring epididymal physiology in humans conducted during the s and s clearly support the concept that the epididymal secretome is essential for the acquisition of fertilizing ability by the male gamete.

The role of the human epididymis in sperm function has been questioned. Even though all the information regarding functions of the excurrent duct obtained with animal models cannot be extrapolated to humans, it remains true that the epididymis is essential for sperm function in our species.

A summary of comparisons between human and rodent epididymides is presented in Table I. Recent studies performed with laboratory and domestic animals have shed light on the mechanisms of epididymis—sperm interaction and how epididymal gene expression is regulated. The role of extracellular microvesicles epididymosomes in transferring proteins to the maturing spermatozoa and in trafficking miRNAs along the male tract is of particular interest.

Epididymosomes are also secreted by the epididymal epithelium in humans, and their functions in sperm maturation cannot be excluded. The possibility that epididymosomes transport small RNAs that modulate sperm functions is particularly intriguing. There is increasing evidence that parental lifestyle and the environment influence phenotypes of the next generation Rando and Simmons, It has recently been demonstrated in rodents that small RNAs derived from transfer RNA tRNA degradation are acquired by spermatozoa during epididymal transit; these small tRNAs mediate epigenome modifications of the male gamete Sharma et al.

If such epigenetic modifications to sperm exist in humans, then ART using sperm collected at different sites along the male tract should be seriously re-evaluated. Obviously, there are major aspects of epididymal physiology, which remain to be explored. Dr Muriel Kelly is acknowledged for text editing. Both authors were equally involved in conception and writing of this review.

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In the last 50 years, the creation of epididymal fertility profiles in laboratory animals was followed by recognition of new sperm maturation-related parameters organization of the acrosome, of the sperm plasmalemma, and —S—S— -based structural change which made it possible to confirm that a similar pattern of sperm maturation obtains in man.

The novel sperm storage function of the cauda epididymidis in therian mammals is regulated by androgen, usually in conjunction with the low temperature of the scrotum. The temperature-dependence of the scrotal cauda is reflected in the secretory and ion transport functions of the epithelium, in its duct dimensions and so in sperm storage capacity.

Moreover, a variety of indirect evidence suggests that an elevated temperature of the cauda created by clothing may be compromising its function in man. The pattern of change in the sperm plasmalemma involving sterols, and also glycosylphosphatidylinositol-linked macromolecules as spermatozoa enter the cauda region, may underlie the need for their capacitation subsequently in the female tract.

Finally, despite the still relative paucity of comparative evidence, we can consider now why the epididymis has come to be organized as it is. At the Worcester Foundation for Experimental Biology, Shrewsbury, Massachusetts, USA in , I joined the laboratory of MC Chang, which was focused on in vitro fertilization, cross-species fertilization, sperm capacitation, sperm transport in the female, the Fallopian tube, and implantation of the embryo.

At that time, Chang's group had no specific interest in the epididymis, which was something of a scientific backwater compared to the focus then on the testis. I first became involved with the epididymis in asking whether, as spermatozoa are gaining the ability to fertilize there, they require the same period of capacitation as those from the cauda region — a point answered later for the pig, whose upper-corpus spermatozoa are capacitated more rapidly than those from the cauda.

In the early s, specific information as to the fertilizing ability of spermatozoa in the epididymis was limited to the guinea pig, 2 and rat, 3 but there was none for the rabbit - my sperm capacitation model. I therefore created a fertility profile of the rabbit epididymis by tubal insemination of sperm aliquots from its successive segments via a flank incision.

On the basis of fertilization rates and sperm numbers on the eggs, this revealed an exponential development of fertilizing ability beginning in the mid-corpus region, completed by the time spermatozoa reach the proximal cauda. However, the profile that obtains in the rabbit is not universal. It is skewed further towards the cauda epididymidis in the hamster, 6 whereas some pig spermatozoa first gain the ability to fertilize in the upper corpus region.

Some years later, by the use of X-irradiation as a marker, 7 the relative competence of the spermatozoa in different regions of the rabbit cauda was assessed by mixed vaginal insemination of two equal populations.

In accordance with the observation that stimulation of the sympathetic vas deferential nerve elicits tubular contractions only of the vas and main body of the cauda, 9 repeated mating in the rat almost emptied these two regions - but with no change in sperm numbers in the upper cauda. As a sequitur to establishment of a fertility profile, the role of specific epididymal regions was examined by ligation of the epididymis Figure 1a.

Although this approach proved less successful in the hamster, 6 rabbit spermatozoa became fertile throughout the epididymis up to the distal limb of the caput flexure when withheld for 8—12 days above ligatures in the corpus region.

This failure indicated that the head of the rabbit epididymis has an essential role in the development of the sperm's ability to fertilize oocytes. Secondly, the fact that highly motile spermatozoa from the proximal caput of the ligated epididymis could not do so pointed to the involvement, beside motility, of other facets of the sperm cell in this maturation.

Subsequent observations demonstrated that development of the sperm's fertilizing ability in the epididymis also involves change in, a the sperm plasmalemma, b the acrosome, and c the structure of organelles in the sperm head and tail. Note the distended tubules proximal to the point of ligation. Spermatozoa released from these tubules were often highly motile but could not fertilize oocytes; nor did they display the tendency for head-head agglutination seen typically in mature spermatozoa.

In the course of epididymal ligation experiments, it became apparent that highly motile rabbit spermatozoa from the proximal caput did not undergo the head-to-head auto-agglutination typical of mature spermatozoa of most eutherian mammals when suspended in a serum-containing medium with man a notable exception in this regard.

Most caput spermatozoa displayed a relatively slow electrophoretic mobility and required about 4 min to adopt a head-to-anode orientation. By contrast, cauda spermatozoa not only displayed a greater electrophoretic mobility but assumed a tail-to-anode configuration within ca.

Diagram of the electrophoretic behavior of rabbit epididymal sperm populations from the caput and cauda regions, respectively. Not only do cauda spermatozoa exhibit a superior electrophoretic mobility, but the great majority assumes a tail-to-anode orientation in about 1 min, whereas caput spermatozoa slowly adopt a head-to-anode orientation in about 4 minutes.

Early investigations of epididymal change in the sperm surface also brought two misconceptions in this regard. Relying on cationized ferric colloid and fluorescinated lectins as surface markers, I first concluded that spermatozoa of monotremes, birds excepting passerines and reptiles do not undergo surface change during Wolffian duct passage.

A second misinterpretation was viewing epididymal change in the sperm plasmalemma solely in terms of fertilizing ability, the current picture suggesting that elements of this relate very much also to sperm storage in the cauda. Yet some rat spermatozoa develop the ability to fertilize in the lower corpus region before any such surface modification. It seems most likely that the late sperm surface acquisition of HIS protein and CD52 relate rather to the longevity of sperm survival in the cauda.

That the receptor for HIS protein evidently first appears on spermatozoa in the upper regions of the epididymis, 23 is a further indication that some aspects of sperm surface change during epididymal transit relate not to fertilizing ability per se but rather to prolongation of the life of spermatozoa in the cauda region. The evidence points to the therian acrosome as undergoing epididymal maturation-related changes at two levels — in its morphology, and in the organization of its matrix. Measurement of sperm head dimensions using a camera lucida confirmed this, 25 with electron microscopy showing that an elongated margin of the acrosome in immature spermatozoa then retracts to form the asymmetrical bulbous border seen in mature rabbit spermatozoa.

A further and more subtle aspect - a reorganization of components within the acrosomal matrix during epididymal passage - has been described in such species as the hamster, guinea pig and boar.

Rather, the example of a buckled rabbit sperm head within the zona pellucida ZP Figure 3 points to —S—S— -stiffening of the nucleus and perinuclear matrix as an adaptation to the challenge of penetrating an unusually robust egg coat. Electron micrograph of a rabbit sperm head in the act of penetrating the zona pellucida ZP.

In this example, the sperm head has buckled at the point marked by arrow heads. By the early s, recognition of four parameters related to sperm maturation in the epididymis motility, acrosomal modification, sperm structure, sperm plasmalemma , made it possible to probe the status of spermatozoa in the human epididymis. At that time, there was only the early report by Belonoschkin 39 that human spermatozoa acquire the capacity for progressive motility there.

Moreover, evidence of the success of high epididymo-vasostomy, 40 and fertile spermatozoa withdrawn from a caput cyst 41 cast some doubt as to whether epididymal maturation in man resembles that in the animals so far examined.

In fact, the changes human spermatozoa undergo in traversing the epididymis prove to be comparable. Within the epididymal population, the morphology of the sperm head was highly variable as a consequence of defects arising during spermiogenesis, but the human acrosome did not exhibit any change in its form after spermiation.

On the other hand, we observed that human spermatozoa transiting the epididymis clearly undergo maturation-associated changes in the plasmalemma, in the structural character of the sperm head and tail, and in the capacity for motility. Modification of the human sperm surface by epididymal secretions was later confirmed by the use of immunocytochemical techniques.

As for their motility, spermatozoa released from the caput were immotile or displayed only a weak wide thrashing movement that produced little or no forward progression. Progressively motile spermatozoa, characterized by a stiff tail beat of limited sweep, were first seen in the population released from the lower corpus region, and then more so in cauda spermatozoa.

However, unlike the picture coming from animals, many cauda spermatozoa displayed poor forward motility or none. Although human spermatozoa thus undergo an epididymal maturation broadly comparable to that in animals, to what extent this depends on any one region of the epididymis is not yet clear, the functional evidence being derived necessarily from clinical situations.

Cases involving epididymo-vasostomy showed higher pregnancy rates the lower the anastomosis along the epididymal duct.

In discussing the enigma of scrotal evolution with medical students in , I asked for suggestions as to the adaptive significance of this. One student suggested that this development may relate not to the testis, but rather to sperm storage in the epididymis.

That idea struck an immediate chord, in view of our focus then on the white-tailed rat M. Although the scrotal anatomy varies among mammals, a similar pattern occurs in other groups including the bushbaby, G. A further example is seen in the laboratory rat, and others are not uncommon among widely different taxa, 50 lending credence to the possibility that the cauda's sperm storage function was a major determinant of scrotal evolution.

This view illustrates the localized fur-free segment overlying the cauda epididymidis. Arrows mark the furred region occupied by the testes. The scrotal surface over the testes is heavily furred, whereas the carunculated region overlying the cauda is bare.

It has long been known that body temperature suppresses sperm storage in the cauda. Among other significant consequences, the time of sperm transit in cryptepididymal rabbits was reduced to 2—5 days from ca. A further outcome of the imposition of body temperature on the epididymis was a reduction of the diameter and length of the duct in the cauda region 57 Figure 5 , and so in its storage capacity. Consequently, over a series, cryptepididymal rats ejaculated only ca.

Although such cryptepididymal males fathered litters, 52 this picture raises an issue as to the impact of sperm numbers in a natural setting. In the case of the rat at least, as more spermatozoa were inseminated, more reached the oviduct ampulla and fertilization occurred sooner.

In b the diameter and length of the distal segment are reduced. Note that the epididymis in b remained in continuity with a normal scrotal testis, and had a normal sperm number in the caput.

C: The lower region of the corpus epididymidis. V: the vas deferens. Histogram of the mean number of spermatozoa produced at ca. Histogram, for four males, of the percentage rat eggs fertilized by 8—10 h postovulation after either one or two ejaculations, or one ejaculation followed by mating with a vasectomized male. The sperm numbers contributed by a second ejaculate clearly favor earlier fertilization.

In the latter [ Figure 6 ] and in man alike [ Figure 8 ], the cauda's minimal capacity is reflected in a modest first ejaculate and then a precipitous fall in the sperm numbers produced in subsequent ejaculates.

In addition, the percentage motility in sperm populations released from the human cauda is lower than that from the corpus. Unlike the minimal consequence of this in animals, prolonged abstinence in man resulted in a major reduction in the motility index of the first ejaculate produced thereafter. The figure for each ejaculate is expressed as the percentage of the total produced.

While much has emerged about the epididymis over the last 50 years, puzzles remain at several levels. In particular, the sperm maturation and sperm storage functions of the therian epididymis raise a fundamental question as to why it is organized as it is, given the absence of these functions where fertilization is external; e.

The few observations on subtherian vertebrates indicate that where fertilization is internal, as in elasmobranchs, reptiles, birds and monotremes, a form of sperm maturation appears in the excurrent duct.