Acrosomal Defects Research Articles

Assessment of the relationship of sperm morphology with seminal and other clinical conditions of semen donors.

The occurrence of abnormal forms of spermatozoa in human semen is quite common. According to WHO, semen is considered normal even if it contains 50% morphologically abnormal spermatozoa. This study assessed whether the sperm morphology maintains any relation with the relevant clinical conditions of the semen donor. One hundred samples representing normal and different types of male factor etiologies underwent semen and morphological analysis. Clinical information such as race, age, weight, profession, medication, medical history, and smoking habit of the semen contributors were recorded. The influence of seminal and clinical features on sperm morphology was evaluated with multiple regression analysis. Head abnormalities were more common than tail abnormalities. Acrosomal defects and coiled tails were the most prevalent head and tail abnormalities, respectively. Regression analysis failed to confirm any strong association between sperm morphology and other seminal parameters. Accessory gland-related seminal parameters such as viscosity, volume, pH, and liquefaction showed the least association with the morphological variability. Sperm morphology also showed poor correlation with race, age, weight, smoking habit, and work environment.

Brief clinical report sperm acrosome defects in a patient with Aarskog‐Scott syndrome

Brief clinical report sperm acrosome defects in a patient with Aarskog‐Scott syndrome

Effects of products of activated immune cells and recombinant cytokines on spontaneous and ionophore-induced acrosome reaction.

The purpose of this study was to examine whether the products of activated immune cells influence spontaneous and ionophore-induced sperm acrosome reaction. The spontaneous and ionophore-induced acrosome reaction were evaluated by staining with fluorescein isothiocyanate (FITC) Pisum sativam agglutinin after incubation in capacitating media supplemented with either supernatants from Con-A activated leukocyte cultures or human recombinant (r) IL-1 beta, TNF-alpha, and INF-gamma. The supernatants from Con A-activated peripheral blood leukocyte cultures at 1:1 and 1:10 dilution significantly increased the rate of spontaneous acrosome reaction (P < 0.001 and P < 0.01). Along with displayed abnormally elevated levels of spontaneous acrosome loss, sperm cells showed an insufficient ability to undergo acrosome reaction in response to the ionophore treatment. Recombinant IL-1 beta at increasing concentrations from 30 to 3 x 10(4) U/ml did not have an effect on spontaneous and ionophore-induced acrosome reaction. In contrast, spermatozoa that underwent capacitation in media with 7 x 10(3), 7 x 10(4), and 7 x 10(5) U/ml of rINF-gamma showed a significant increase in spontaneous and induced acrosome reaction compared to the control (P < 0.001). Recombinant TNF-alpha at concentrations of 3.5 x 10(3) U/ml and 3.5 x 10(4) U/ml significantly inhibited ionophore-induced acrosome reaction (P < 0.001). Both rINF-gamma and rTNF-alpha together revealed an effect on the acrosome reaction similar to Con-A generated supernatants (1:1 and 1:10 dilution) only at the highest concentrations. Some cases of infertility may result from a defective acrosome reaction (premature acrosome loss or insufficient acrosome response to the stimulants) caused by products of activated lymphocytes and macrophages that are released into the male and female reproductive tracts.

Relationships between motility parameters, morphology and acrosomal status of human spermatozoa

A total of 130 semen samples were examined for motility (by computer-assisted sperm analysis), morphology and acrosomal status. A high positive correlation was found between percentages of normal forms and progressive motility in the whole semen (r = 0.539, P < 0. 0001) as well as in the Percoll fraction (r = 0.702, P < 0.0001). Among the specific abnormalities, acrosome defects were most highly correlated with progressive motility (r = -0.492, P < 0.0001, in the Percoll fraction). The percentage of total spontaneously acrosome-reacted spermatozoa in the Percoll fraction was negatively correlated with the progressive motility (r = -0.499, P < 0.0001) and with the percentage of normal forms (r = 0.430, P < 0.0001). Surprisingly, the percentage of total spontaneously acrosome-reacted spermatozoa was poorly linked with head abnormalities but displayed significant positive correlations with the percentages of bent tails (r = 0.359, P < 0.0001) and of coiled tails (r = 0.371, P < 0.0001). These data suggest that sperm defects are often linked together, reflecting spermiogenesis and/or epididymal dysfunctions.

Deleterious effects of khat addiction on semen parameters and sperm ultrastructure.

The semen parameters and sperm ultrastructural morphology have been described in semen samples from two groups of Yemeni subjects. The first 'exposed' group comprised 65 khat addicts, while the second control group included 50 non-khat addict subjects. The mean age was 39.94 +/- 13.85 and 35.72 +/- 11.35 years in the exposed and control groups respectively, without a significant difference. The mean duration of khat addiction among the addicts was 25.34 +/- 12.96 years (range 6.00-48.00). Statistically significant differences were detected between the semen parameters of the two groups. Such parameters, including semen volume, sperm count, sperm motility, motility index and percentage of normal spermatozoa, were lower among addicts. Significant negative correlation was also found between the duration of khat consumption and all semen parameters (r ranged from -0.30 to -0.74). At the transmission electron microscopy level, a counting system was incorporated to compare the numbers of normal spermatozoa with deformed and dead spermatozoa in ultrathin plastic sections. The total mean percentage of deformed spermatozoa was approximately 65%. Different patterns of sperm deformation were demonstrated, and included both the head and flagella in complete spermatozoa, aflagellate heads, headless flagella and multiple heads and flagella. Deformed heads showed aberrated nuclei with immature nuclear chromatin and polymorphic intranuclear inclusions; these were associated with acrosomal defects. The deformed flagella demonstrated numeric aberrations of the axonemal 9 + 2 configuration and structural defects of their associated elements. Persistent cytoplasmic droplets were observed frequently. This study has shown for the first time the deleterious effects of khat addiction on semen parameters in general and sperm morphology in particular of all addicts, especially those who have consumed khat for longer periods of time.

Acrosomal status in fresh and frozen/thawed stallion spermatozoa evaluated by scanning electron microscopy.

Semen from stallions with equal fertility at natural services, but yielding semen with either satisfactory or poor fertilizing capability after freezing and thawing, was processed for scanning electron microscopy before and after freezing and thawing. In all fresh semen samples the following three categories of acrosomal defect were noticed: (1) minor fenestrations of the plasma membrane (PM) and outer acrosomal membrane (OAM), (2) complete vesiculation and loss of PM and OAM and (3) lack of a large circular part of PM and OAM. The frequency of these defects ranged from 15% to 27%. All frozen and thawed samples displayed defects of categories 1-3 at similar frequencies as the fresh ones. However, additional defects categorized as: (4) major fenestrations of PM and OAM and (5) complete vesiculation of PM and OAM without loss of the vesicles were noted upon freezing and thawing. The total frequency of defects categorized as 4 and 5 ranged from 8% to 21%, and they seemed to be more frequent in stallions with poor fertility after freezing and thawing although the difference was not significant. Moreover, a particular defect categorized as (6) loosening of the whole acrosomal cap was found exclusively in stallions yielding semen with poor freezability.

Reproductive Characteristics of Male Florida Panthers: Comparative Studies from Florida, Texas, Colorado, Latin America, and North American Zoos

Testicular volume, semen traits, and pituitary-gonadal hormones were measured in populations of Felis concolor from Florida, Texas, Colorado, Latin America, and North American zoos. More Florida panthers (F. concolor coryi) were unilaterally cryptorchid (one testicle not descended into the scrotum) than other populations (43.8 versus 3.9%, respectively). Florida panthers also had lower testicular and semen volumes, poorer sperm progressive motility, and more morphologically abnormal sperm, including a higher incidence of acrosomal defects and abnormal mitochondrial sheaths. Transmission electron microscopy revealed discontinuities in the acrosome, extraneous acrosomal material under the plasma membrane, and remnants of the golgi complex under the acrosome. No differences were detected in mean-circulating follicle-stimulating hormone, luteinizing hormone, or testosterone between Florida panthers and other populations of mountain lions. Seminal traits and concentrations of follicle-stimulating hormone, luteinizing hormone, and testosterone were similar between cryptorchid and noncryptorchid Florida panthers. Animals with F. concolor coryi ancestry were categorized on the basis of amount of genetic variation (low = type A; medium = type B; high = captive Piper stock). Compared to counterparts, type A Florida panthers had the lowest testicular volume and sperm-motility ratings and were the only animals exhibiting unilateral cryptorchidism. These results demonstrate the existence of major morphological and physiological differences among populations of F. concolor, a finding potentially related to differences in genetic diversity.

Effect of acrosome defects and sperm chromatin decondensation on fertility and litter size in the rabbit. Preliminary electron-microscopic study.

Sections of ejaculated spermatozoa from rabbits with known fertility were observed by transmission electron microscopy. Acrosome defects, odd head shapes, the presence of spermatids and the decondensation of sperm nuclei were recorded. The fertility negatively correlated with the number of acrosomal defects, while litter size was negatively related to nuclear decompaction. Sperm nuclear decondensation was present in all ejaculates. Its frequency was correlated with that of spermatids in ejaculates.

Effect of storage on sperm membrane integrity and other functional characteristics of canine spermatozoa: In vitro bioassay for canine semen

The effect of storage of canine semen on sperm membrane integrity, as determined by the hypoosmotic swelling test, and on other functional characteristics of the canine spermatozoa was evaluated by established procedures. The results of this study indicated that storage of canine semen at a chilling temperature of 5°C for 24 h did not significantly impair the physical and functional characteristics of the canine spermatozoa. The overall mean percentage of motility, hypo-osmotic swelling response, which assessed sperm membrane integrity, acrosome-reacted spermatozoa, acrosomal defects, and the percentage of live spermatozoa, did not significantly differ between the fresh and chilled semen samples. However, storage altered the rate of motility and acrosome reaction. The percentage of acrosome reaction in the canine capacitating medium peaked earlier in chilled than in fresh semen. It is probable that storing semen at 5°C initiated/triggered the acrosome reaction. This did not amount to impairment of functional properties. Significant correlations were observed between hypo-osmotic swelling vs motility (r=0.98, P<0.002); hypo-osmotic swelling vs acrosome reaction (r=0.83, P<0.08); and acrosome reaction vs motility (R=0.89, P<0.04) in the fresh semen, and between hypo-osmotic swelling vs motility (r=0.87, P<0.05) and hypo-osmotic swelling vs acrosome reaction (r=0.56, P<0.05) in the chilled semen. It was concluded: that 1) storage of canine semen at 5°C for 24 h did not significantly impair the physical and functional integrity of the spermatozoa; 2) the significant association between motility or acrosome reaction vs hypo-osmotic swelling indicates their value in assessing sperm viability; and 3) the hypo-osmotic swelling assay could have predictive value in screening out subfertile males with apparently normal spermiograms.

Influence of freezing process on “in vitro” capacitation of ram semen

The aim of the current study was to evaluate the effects of different concentrations of rainbow trout seminal plasma (RTSP) (0.1%, 1% and 10%) in extenders containing either egg yolk or lecithin for use in Awassi ram semen cryopreservation. Pooled sperm were diluted in a two-step dilution method to a final concentration of 1/5 (semen/extender) in egg yolk or lecithin extender containing no RTSP, 0.1%, 1% or 10% RTSP (v/v). Semen samples were assessed for sperm motility, plasma membrane integrity [hypoosmotic swelling test (HOST) and Hoechst 33258] and defective acrosomes [FITC-conjugated Pisum sativum agglutinin (PSA-FITC)] at the following five time points: after dilution with extender A; after equilibration; and post-thaw at 0 h, 3 h and 5 h. Malondialdehyde (MDA) was examined only after thawing. Freezing and thawing procedures (dilution, equilibration and post-thaw incubation at 0 h, 3 h and 5 h) negatively affected the motility (P < 0.001) and acrosome integrity (P < 0.001). Additionally, freezing and thawing negatively affected the plasma membrane integrity, as determined by the HOST and Hoechst 33258 (P < 0.001). The extender group affected the motility (P < 0.001) and the HOST results (P < 0.001). Levels of MDA in the egg yolk extender with 1% RTSP group were significantly lower than in the lecithin control group (P < 0.05). In conclusion, the egg yolk extender groups that were supplemented with 10% and 1% RTSP provided greater cryoprotective effects for semen survivability during 5 h incubation than the other extender groups.

Testicular ultrastructure of Zebu bulls in Costa Rica.

The testicular ultrastructure of sexually mature Zebu (Bos indicus) bulls from Costa Rica was studied in relation to their classification based on andrological examinations undertaken in the field. Based on the testicular consistency at palpation, each bull was assigned to one of three groups, ranging from normal (Group A) to markedly reduced testicular consistency (Group C). The ultrastructure of the clinically normal testicle (Group A) in the Zebu bull resembled that of Bos taurus. In testicles with a slight to moderate reduction of testicular consistency (Group B) degenerated primary spermatocytes and spermatids were common at all stages of the seminiferous cycle. Abnormalities in the condensation of the chromatin, acrosomal defects, and the presence of degenerated cells and cellular debris were the most common of disturbances found. In testicles from bulls with a marked reduction of testicular consistency (Group C) the seminiferous epithelium of most tubules showed degenerative changes, thereby making it impossible to classify the stage of the cycle. The changes were mainly restricted to spermatocytes and spermatids, whose relative numbers were reduced. The number of cells undergoing meiotic divisions was also greatly reduced. Changes in the spermatids were also found including the appearance of severe acrosomal defects, such as acrosomal pouches, the failure of nuclear elongation and clear defects in chromatin condensation. The present ultrastructural findings in Bos indicus do not differ from the picture of normal testicular structure and of testicular degeneration usually found in Bos taurus bulls.

REVIEW

Disturbances of acrosomal development and function significantly impair the fertilizing capacity of spermatozoa. Therefore, evaluation of acrosomal morphology and function is of particular importance in the diagnostic testing of male infertility. Acrosomal disturbances include either specific defects showing a complete absence of certain acrosomal structures or various acrosomal malformations in combination with nuclear or flagellar defects which indicate acquired testicular disorders. As examples of specific acrosomal defects, the syndrome of round-headed spermatozoa (globozoospermia), the crater defect syndrome and the syndrome of decapitated spermatozoa are discussed. In addition to disturbances of acrosomal morphology, the assessment of acrosomal proteinase activity and the acrosome reaction as a method of evaluating impaired acrosomal functions is discussed. Clinical examples demonstrate the importance of these sperm function tests in the fertility testing of infertile men.

The spermicidal effect of ethylene dibromide in bulls and rams

The spermicidal effect of ethylene dibromide (EDB) in bulls and rams is reviewed. Following oral or parenteral administration EDB was found to cause, by its alkylating effect in the testes of treated bulls and rams, lysis of the chromatin of the elongating spermatids during the time of somatin histones replacement by the sperm protamines. However, while in the bulls the abnormal spermatozoa issued from the affected spermatids were also collected in the ejaculates, this was not the case with treated rams. In the latter animals the abnormal spermatids seem to be phagocytized in the epididymis before their arrival in the ejaculate. In addition, whereas the alkylating effect of EDB occurred also in the upper parts of the epididymis of the bulls, causing tail and acrosome defects to the spermatozoa, in the rams such an effect seems to occur all along the epididymal duct. These differences between bulls and rams in the sites of the genital tract where the drug takes effect, and in the mechanism of this effect, reveal probable differences in the physiology of the reproductive tract between these species.

Diadem/crater defects in spermatozoa from two related angus bulls

The diadem/crater defect was studied over several months in two related 20-month-old Angus bulls. In bull 1, diadem/crater defects were present in 2-99% of ejaculated spermatozoa at various times during the evaluation period. In bull 2, affected cells varied from 20% to 94%, with other abnormalities (head and acrosome defects, coiled tails, proximal cytoplasmic droplets) also common. Single sire mating trials conducted over 26 days during an apparent recovery phase showed normal fertility (approximately 50% pregnancies per estrus exposed). Both resting and gonadotropin-releasing hormone (GnRH)-stimulated testosterone values were within nor-mal limits. Histopathological evaluation of testes showed no obvious hypoplastic, inflammatory, or degenerative condition. Electron microscopy of ejaculated spermatozoa demonstrated the characteristic diadem pattern of craters in the equatorial region of the head. Many cells from bull 2 contained large craters in other regions of the nucleus. Electron microscopy of testicular tissue demonstrated nuclear invaginations lined by a single unit membrane in round spermatids. Lesions in elongated spermatids were more pronounced, with curling of the nucleus and large membrane-filled cavities in the chromatin occurring in addition to craters in the equatorial region of the nucleus.

Oocyte recovery, maturation and fertilization in vitro in the puma (Felis concolor)

Eight female pumas were treated i.m. with 1000 (N = 5) or 2000 (N = 3) i.u. PMSG followed 84 h later by 800 i.u. hCG. Eggs were recovered 24-26 h after hCG from ovarian follicles by using laparoscopy and transabdominal aspiration. Mature eggs were inseminated in vitro 4-6 h later whereas immature eggs were cultured for 24 h and then inseminated. Electroejaculates from 3 pumas were diluted with mKRB before insemination to evaluate the influence of sperm concentration on fertilization. Seven of 8 pumas responded with follicle development, and 140 eggs were recovered from 145 follicles (96.6%; 77 mature, 43 immature, 20 degenerate eggs; mean +/- s.e.m., 20.0 +/- 5.9 eggs/female). Overall fertilization rate was 43.5% (total eggs fertilized = 40) despite using inseminates containing 82-99% pleiomorphic spermatozoa. Of the 36 immature oocytes matured in vitro and inseminated, 12 were fertilized even though 50% of the inseminating spermatozoa contained an acrosomal defect. Fertilization rate of mature oocytes collected from follicles appeared unrelated (P greater than 0.05) to PMSG dose or number of spermatozoa/inseminate. This study demonstrates that a high proportion of follicular eggs can be recovered laparoscopically from adult pumas treated with PMSG and hCG. These gametes are capable of being fertilized in vitro (immediately or after maturation in vitro) even with low quality semen with a high incidence of sperm pleiomorphisms.

Three Types of Acrosomal Aberrations of Bull Spermatozoa and their Relation to Fertility

The effect of acrosomal aberrations of the spermatozoa of Finnish Ayrshire bulls on the corrected non-return rate within 60 days of the first 500 inseminations was studied. The material consisted of sperm samples examined by the artificial insemination societies. All samples had been accepted for use in artificial insemination. One Giemsa-stained slide was studied for each of the 95 bulls concerned. Samples showing distinct acrosomal defects were studied by electron microscopy. Three different types of acrosomal aberration were found. One was obviously associated with subfertility in all 6 bulls in which it was detected.

Morphological defects of the acrosome in boar spermatozoa

Morphological examination of semen from 17 boars of five breeds showed the presence of acrosome defects in 11 boars from four breeds. Two distinct types were seen; 'knobbed' sperm (type 1), of which two forms were found to be present by electron microscopy, and an uneven swellling of part of the acrosome (type 2) whose contents consisted of cytoplasmic and membrane-like material. The incidence of 'knobbed' sperm ranged from 0.2 to 6.3 per cent. Type 2 abnormalities were seen in only two boars, at 0.66 and 1.33 per cent.

The sperm acrosome: functional and clinical aspects.

The acrosome of mammalian spermatozoa contains high amounts of acrosin, which is believed to be essential for gamete fusion, particularly for binding to, and penetration of, the zona pellucida. In addition, its activation from proacrosin seems to be associated with the capacitation process. Furthermore, it might facilitate cervical mucus penetration and intrauterine sperm migration by releasing kinins from kininogen, as well as participating in the acrosome reaction and in chromatin decondensation in the oocyte. Considering these functions of the acrosome during the process of fertilization, the morphology and functional integrity of the acrosome in ejaculated human spermatozoa are of fundamental importance in attachment, species-specific binding and zona penetration preceding gamete fusion. It is therefore mandatory to focus on acrosomal membrane functions and consider particularly the occurrence of acrosomal disturbances in spermatozoa from men of barren marriages. For this purpose, biochemical and immunocytochemical methods have been used to investigate acrosin activity and possible alterations of the acrosomal membrane system in different groups of sub- and infertile patients. Of particular interest is the ability of spermatozoa to undergo the acrosome reaction, which can be studied using the triple-stain technique. Of all the spermatological groups investigated (normo-, astheno-, oligo-, terato- and polyzoospermia), polyzoospermic semen samples showed severe acrosomal disturbances indicating functionally defective acrosomes which might hinder fertilization. The data indicate the need for the introduction of acrosomal markers in clinical andrology for proper diagnosis of acrosomal sperm defects.

Spermiogenic, epididymal, and spermatozoal damage induced by a peritesticular injection of ethylene dibromide to rams

The effects of a peritesticular injection of ethylene dibromide (EDB) on the germ cells, epididymis, and spermatozoa of rams was examined by removing each injected testis and epididymis at different times after treatment and by monitoring the seminal characteristics of ejaculates. A high incidence of abnormal elongating and elongated spermatids was observed in the testes of treated rams 48 h after injection. At this time the epithelium of the corpus and cauda epididymidis was damaged in the majority of observed rams, and the spermatozoa in these segments were abnormal, mainly with acrosomal defects, denuded forms and denuded tailless forms. Apparent phagocytosis of spermatozoa was also observed in these portions of the epididymal duct. Ejaculates collected as early as 48 h after injection had a very low sperm density and large percentages of spermatozoa with acrosomal and tail abnormalities. A dose-reponse effect was obtained, and the reversibility of the effect of a low dose of EDB on sperm morphology was demonstrated in the rams by semen examination.

P-Aminobenzamidine, an acrosin inhibitor, inhibits mouse sperm penetration of the zona pellucida but not the acrosome reaction.

The effect of p-aminobenzamidine (pAB), an inhibitor of mouse sperm acrosin, on mouse sperm capacitation, motility, acrosome loss and fertility in vitro was examined using zona-intact and zona-free eggs. With intact eggs, concentrations of pAB ranging from 0.1 to 1.0 mM in the sperm preincubation medium effectively inhibited fertilization (13-0%, respectively), but these same suspensions (10(6) cells/ml) showed high rates of fertilization with zona-free eggs (100-95.3%); with the lower concentration of 10(5) cells/ml, fertilization rates of zona-free eggs decreased with increasing concentrations of pAB (100-55%). Washing of treated samples gave fertilization rates similar to control samples (87.1 and 84.6%, respectively), indicating that inhibition was reversible and that there had been no interference with the capacitation process. Whiplash motility was also observed in all samples, suggesting that the apparent inability to penetrate the zona might be due to an acrosomal defect. This was confirmed by electron microscopic examination of treated sperm samples. In high concentrations of pAB, many cells had undergone the acrosome reaction, i.e. membrane vesiculation, but acrosomal matrix dispersal was inhibited. These results are consistent, therefore, with a role for the acrosomal enzyme acrosin in matrix dispersal, but not the acrosome reaction itself, and in penetration of the zona pellucida.