Disappearance Of Spermatozoa Research Articles

Morphological changes of cauda epididymis, sperm infiltration into cauda epididymis, sperm storage and sperm disappearance of cauda epididymis in Rhinolophus ferrumequinum korai (Chiroptera: Rhinolophidae)

In this study to investigate the male reproductive cycle of Rhinolophus ferrumequinum korai, we focused on monthly morphological changes of cauda epididymis, sperm infiltration into cauda epididymis, sperm storage and sperm destruction. The caudal epididymal reproductive cycle consisted of two successive purge stages. The first stage of sperm disappearance occurred from April to June. This was a preparation phase for accepting new sperm produced by spermatogenesis, and entailed removing long-stored spermatozoa from the cauda epididymis during the long hibernation period. The second stage of sperm disappearance occurred from July to August, to remove malformed spermatozoa and other residues that were formed during the spermatogenesis process. Therefore, cauda epididymis cleansing lasts about 5 months, from April to August. This period is called the cleansing period. Sperm destruction was achieved by regulating leukocyte phagocytosis and the secretion and uptake by epithelial cells of cauda epididymis. Compared to the author’s previous studies, morphological traits of the cauda epididymis changed 1 month earlier. This suggests that temperature increase can impact reproductive development of the epididymis. Caudal epididymal sperm did not show any sudden morphological change during the long hibernation period after mating. This might be related to a low metabolic rate during hibernation.

OUTCOME AND LATE FAILURES COMPARED IN 4 TECHNIQUES OF MICROSURGICAL VASOEPIDIDYMOSTOMY IN 153 CONSECUTIVE MEN

Vasoepididymostomy remains one of the most technically challenging procedures in all of microsurgery. The technique has evolved from an end-to-end, to an end-to-side technique, then to intussusception end-to-side methods. We recently reported the superiority of 2-suture longitudinal and 3-suture triangulation intussusception techniques in rats. In the present study we report our results in humans. We evaluated all vasoepididymostomies performed by 1 surgeon from January 1992 until the present for patency, pregnancy and for disappearance of sperm after initial return of sperm to the ejaculate. We recorded the results of 153 consecutive vasoepdidymostomies done by 1 surgeon (MG) from January 1992 until February 2004. Four techniques were used, namely end-to-end (EE), end-to-side (ES), 3-suture triangulation intussusception (TIVE) and 2-suture longitudinal intussusception (LIVE). Data collected included technique, months of followup, sperm density, motility and morphology (WHO 1992 criteria), pregnancy outcome and late failures. Late failures were defined as having return of sperm to the ejaculate after vasoepididymostomy and then becoming azoospermic on at least 2 subsequent semen analyses. A total of 153 men underwent bilateral vasoepididymostomies. The most recent 17 were LIVE, preceeded by 38 TIVE, 32 ES and 66 EE. Mean followup for the groups were 17.2 (LIVE), 70.8 (TIVE), 116.7 (ES) and 140.2 (EE) months, respectively. Intact sperm were seen in the ejaculates of 12 men (80%) in the LIVE group, 16 in the TIVE group (84%), 20 in the ES group (74%) and 30 men in the EE group (73%). Motile sperm were found in the ejaculates of 10 of 15 (67%) in the LIVE group, 13 of 19 (68%) in the TIVE group, 10 of 27 (37%) in the ES group and 20 of 41 (49%) in the EE group (p =0.2). Mean times for return of sperm to the ejaculate were 2.9, 2.8, 2.8 and 3.5 months, respectively. Pregnancies were reported by 4 men in the LIVE group all before 12 months, 6 in the TIVE group and 3 were by 12 months, and 4 each by the ES and EE groups with 3 and 2 by 12 months (p =0.07). Thus far, there have been no late failures in the LIVE group, only 1 in the TIVE group (8%), 5 in the ES group (50%) and 6 in the EE group (30%) (p =0.04). Although vasoepididymostomy remains a technically demanding microsurgical procedure, recent technical innovations of TIVE and LIVE offer better or comparable outcomes compared with EE and ES procedures with the use of fewer sutures, which simplifies the performance of the anastomosis. In addition, the late failure rate is lower with the use of the intussusception techniques (LIVE and TIVE) with only 1 late failure in 22 men with return of sperm to the ejaculate procedures (4%) compared with 11 of 30 (37%) in the nonintussusception groups (p =0.006).

Changes in gonadal development, androgenic gland cell structure, and hemolymph vitellogenin levels during male phase and sex change in laboratory-maintained protandric shrimp, Pandalus hypsinotus (Crustacea: Caridea: Pandalidae)

Most pandalid shrimps show protandric hermaphroditism, and male sexual differentiation is considered to be controlled by the androgenic gland. In the present study, we examined the histology of gonadal development during the male phase and sex change and the involvement of the androgenic gland in regulating male reproduction in laboratory-maintained Pandalus hypsinotus. Juvenile shrimps developed testicular tissues in the peripheral part of gonads during the age of 16–31 months and produced spermatozoa between 34 and 36 months. After reaching sexual maturity, male shrimps exhibited seasonal testicular development: active production of spermatozoa (February–May), disappearance of spermatozoa (spent, April–June), increase of spermatocytes (May–November), appearance of spermatids and spermatozoa in the gonads (November–February). The androgenic gland cells became larger and the rough endoplasmic reticulum in the cytoplasm developed at male sexual maturity. The cell structure shows that the androgenic gland hormone is a peptide. Furthermore, bilateral eyestalk ablation on immature male shrimps induced hypertrophy of the androgenic gland and acceleration of male sexual maturation. These results indicate the involvement of androgenic gland hormone and some eyestalk factor in regulating male sexual maturation. Over a 1-year laboratory-rearing period, some male shrimps (16.7%) changed sex. In transitional shrimps, testicular tissues in the gonads and androgenic glands degenerated; on the other hand, oocytes started yolk protein accumulation and hemolymph vitellogenin levels became high. These results suggest that androgenic gland degeneration is a trigger for sex change and that the vitellogenin level is a useful marker for sex change.

Comparison of patency rates, pregnancy and late failures in four techniques of vasoepididymostomy in 143 consecutive patients

Comparison of patency rates, pregnancy and late failures in four techniques of vasoepididymostomy in 143 consecutive patients

Rapid disappearance of spermatozoa after vasal occlusion in the dog.

The reproductive system of the male dog is unusual in that the seminal vesicles and bulbourethral glands are absent. Therefore, we chose the dog as a model to evaluate the effect of seminal vesicles on clearance of spermatozoa from the male reproductive tract after vasal occlusion. Thirty adult male beagle dogs with ejaculates containing at least 500 x 10(6) sperm with greater than 90% motility were used for this study. The dogs' vasa were occluded percutaneously using a Vasocclude clip-applying device through a small scrotal puncture site. Dogs were ejaculated and semen analysis was performed before and after vas occlusion. The first 24 dogs were completely azoospermic 1 week following vas occlusion. In order to explain these unanticipated results, an additional 6 dogs were evaluated to determine the specific time course of sperm disappearance from the ejaculate at 1, 3, 5, and 7 days after vas occlusion. The results revealed that spermatozoa were almost completely absent within 1 day after vas occlusion (99.9% reduction, X = 1.0 + 1.1 x 10(6) sperm per milliliter at 1 day, P <.0005 vs prevas occlusion). The rapid elimination of spermatozoa after vas occlusion indicates that sperm transit rapidly through the vas deferens in dogs. Therefore, the delayed clearance of spermatozoa from the ejaculate in humans may be due to sperm storage in the seminal vesicles.

2,4,6-Trinitrotoluene-induced Reproductive Toxicity via Oxidative DNA Damage by its Metabolite

Several epidemiological studies and animal experiments showed that 2,4,6-trinitrotoluene (TNT), a commonly used explosive, induced reproductive toxicity. To clarify whether the toxicity results from the interference of endocrine systems or direct damage to reproductive organs, we examined the effects of TNT on the male reproductive system in Fischer 344 rats. TNT administration induced germ cell degeneration, the disappearance of spermatozoa in seminiferous tubules, and a dramatic decrease in the sperm number in both the testis and epididymis. TNT increased the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) in sperm whereas plasma testosterone levels did not decrease. These results suggest that TNT-induced toxicity is derived from direct damage to spermatozoa rather than testosterone-dependent mechanisms. To determine the mechanism of 8-oxodG formation in vivo, we examined DNA damage induced by TNT and its metabolic products in vitro. 4-Hydroxylamino-2,6-dinitrotoluene, a TNT metabolite, induced Cu(II)-mediated damage to 32 P-labeled DNA fragments and increased 8-oxodG formation in calf thymus DNA, although TNT itself did not. DNA damage was enhanced by NADH, suggesting that NADH-mediated redox reactions involving TNT metabolites enhanced toxicity. Catalase and bathocuproine inhibited DNA damage, indicating the involvement of H 2 O 2 and Cu(I). These findings suggest that TNT induces reproductive toxicity through oxidative DNA damage mediated by its metabolite. We propose that oxidative DNA damage in the testis plays a role in reproductive toxicity induced by TNT and other nitroaromatic compounds.

Study of laser vas deferens occlusion

The objective of this study was to determine threshold levels for high-power laser output Nd:YAG laser photocoagulation and to determine the possible reversibility of laser vas occlusion. The study included vas deferens of 220 rabbits and 20 samples of men in vitro, applying the Nd:YAG laser instrument, doing vasopuncture by a catheter needle, guiding the fiber into the vas, and performing the irradiation occlusion experiment to determine effective threshold value of photocoagulation. The effect and safety of occlusion were followed-up over a year, and reopening a experiment was done in 60 occluded nodes of rabbits. The postoperative sperm disappearance rate was 100%, and reopening rate was 72.7% without obvious complications. High-power lasers may be used as photocoagulation, and its merits are reliable, effective, and rapid recovery. The vas threshold lesion value of rabbits and men in vitro are 50 W/0.5 s, 45 W/1 s, respectively, and irradiation depth reached the middle-ring muscularis.

Morphological and histochemical changes in the epididymis of hamsters (Mesocricetus auratus) subjected to short photoperiod.

The morphological involution and histochemical changes of the Syrian hamster (Mesocricetus auratus) epididymis induced by a short light period were investigated. Under short-day conditions, the epididymis showed marked morphological changes including a decrease in luminal diameter, disappearance of spermatozoa, increase of interductal tissue, increase of intraepithelial lipofuscin deposits, the presence of phagolysosomes in the principal cells and macrophage-like cells, and a considerable modification of most clear cells. With lectin histochemistry changes were found in the glycoconjugates of principal cells of the regressed epididymis, either a decrease (PNA, WGA, HPA and DBA) or an increase (MAA) in the affinity of lectins to the Golgi area, or a decrease (HPA) or an increase (PNA) in lectin binding to stereocilia. Both morphological and histochemical results showed that, under this light condition, the cauda epididymidis presented the most prominent alterations, and that the epididymis showed increased absorptive activity and a decreased synthesis of glycoproteins. All these changes are probably due to the decrease in testosterone levels.

The change of carnitine content in seminal plasma after reversible injection occlusion of vas deferens

The change in carnitine content in seminal plasma after reversible injection occlusion of was deferens (RIOVD) was observed. RIOVD is a safe, effective and simple method of male fertility control. Carnitine was determined by microenzymatic method. The incidence of sperm disappearance increased with the duration of RIOVD and reached 90% at the end of 12 months after operation. Before RIOVD, the mean value of carnitine in seminal plasma was 336.9±78.1 nmol/ml (X±SD, n = 58); after RIOVD, the mean value of seminal plasma carnitine was 112.7±50.7 nmol/ml (n = 172) in the group with sperm disappearance, and 172.5±71.7 nmol/ml (n = 51) in the group without sperm disappearance. There was a significant difference in carnitine content between pre-operation and postoperation (p<0.01). After RIOVD, the carnitine concentration in seminal plasma of the group with sperm disappearance was lower than that of the group without sperm disappearance (p<0.01). The results suggest that carnitine content in seminal plasma following RIOVD may be a reference index for judging the success or failure of the operation.

Sperm precedence in zebra finches does not require special mechanisms of sperm competition

Competition between the spermatozoa of different males to fertilize the eggs of a single female acts as a selection pressure on the behaviour of males and females. However, quantitative predictions about behaviour can only be made if the paternity consequences of different patterns of copulation are known. Because exhaustive empirical measurement of these consequences may be impractical, interest has centred on determining the mechanisms by which sperm competition occurs, knowledge of which may allow consequences to be calculated. One method of elucidating mechanisms of sperm competition is to use mathematical models to determine which mechanisms are necessary or sufficient to account for empirical observations. We use this approach for zebra finches Taeniopygia guttata and show that empirically measured rates of disappearance of sperm from the reproductive tract, and differences in the number of sperm in the first and subsequent ejaculates of each male, are sufficient to account for observed levels of sperm precedence. Special mechanisms of sperm competition, such as displacement or stratification of sperm, are therefore unnecessary to explain sperm precedence in this species.

Mechanisms of sperm competition in birds: mathematical models

We built models of sperm competition and compared their predictions with observations from domestic chickens in an attempt to elucidate the mechanism of sperm competition. The models suggest that (1) observed levels of precedence of sperm are not merely a passive consequence of the greater mortality of sperm from earlier inseminations; (2) displacement of existing sperm from sperm storage tubules by incoming sperm explains observed levels of sperm precedence and disappearance from the reproductive tract, even in the absence of recognition of sperm from different inseminations; (3) stratification of sperm within the sperm storage tubules fails as an explanation of observed patterns of sperm precedence and disappearance because long-term levels of sperm precedence as high as those observed can only be predicted in combination with rates of disappearance of sperm much lower than those observed in chickens. The predictions of sperm precedence levels following multiple inseminations also suggest that displacement rather than stratification is the most likely mechanism of sperm competition in chickens. We discuss the consequences of male or female control of sperm competition, non-uniform distribution of sperm between sperm storage tubules, and variation in sperm precedence with time after the last insemination, and suggest ways in which the models may be used in future to aid in the elucidation of mechanisms of sperm competition.

General and Anomalous Sperm Disappearance Characteristics Found in a Large Vasectomy Series

There is no accepted standard for the time after vasectomy before infertility is achieved. To help address this question, the records of 5,233 vasectomy patients who had had at least 12 ejaculations and had completed semen tests were reviewed. Seventy-five percent were able to fulfill a designated criterion for by 4 months postoperatively, nearly 90% by 6 months, and nearly 99% by 1 year. Also found were a number of individual anomalies, including five instances of transient reappearance of sperm, four late spontaneous reversals after proof of success, and one late delayed success after evidence of failure. Patients can be reassured by the overall efficacy of male sterilization, but physicians also may wish to be aware of the possibility of capriciously intermittent-fitful-sperm.

General and anomalous sperm disappearance characteristics found in a large vasectomy series

There is no accepted standard for the time after vasectomy before infertility is achieved. To help address this question, the records of 5,233 vasectomy patients who had had at least 12 ejaculations and had completed semen tests were reviewed. Seventy-five percent were able to fulfill a designated criterion for success by 4 months postoperatively, nearly 90% by 6 months, and nearly 99% by 1 year. Also found were a number of individual anomalies, including five instances of transient reappearance of sperm, four late spontaneous reversals after proof of success, and one late "delayed success" after evidence of failure. Patients can be reassured by the overall efficacy of male sterilization, but physicians also may wish to be aware of the possibility of capriciously intermittent-fitful-sperm.

Embryonic development in culture of two dasyurid marsupials, Sminthopsis crassicaudata (Gould) and Sminthopsis macroura (Spencer), during cleavage and blastocyst formation.

Embryos of Sminthopsis crassicaudata and Sminthopsis macroura were cultured for up to 96 hours during cleavage and early expansion of the blastocyst in Dulbecco's modified Eagle's medium (DMEG), DMEG containing 2.76 gm/liter sodium lactate (DMEGL), DMEG containing 3.5 gm/liter galactose (DMEGAL), DMEG containing 15 ng/ml progesterone (DMEGP) or 150 ng/ml progesterone (DMEGP10), and DMEGL containing 15 ng/ml progesterone (DMEGLP). The disappearance of sperm was used to indicate the time of ovulation (day 0). Fertilized eggs were found in the uterus at the end of day 1, four-cell stages at the end of day 2, and embryos completing the fourth division by the end of day 3 in S. macroura and day 4 in S. crassicaudata. Estimated developmental times in culture were similar to those obtained in vivo. In both species, the first two divisions take about 24 hours, cleavage is arrested for 24 hours or longer at the rounded four-cell stage, and the third and fourth divisions take a further 24 hours. The blastocyst expands during the next 24 hours in which time the fifth and sixth divisions occur. It was possible to culture embryos from S. macroura but not S. crassicaudata over the four-cell stage to early expanding blastocysts. DMEGAL did not support cleavage in culture. DMEG, DMEGL, DMEGP, DMEGP10, and DMEGLP all supported culture during cleavage and early blastocyst expansion. Blastocyst expansion was slightly enhanced using media containing sodium lactate. More embryos completed the fifth division and formed expanding blastocysts in DMEG, DMEGL, and DMEGLP.

Response of the mouse epididymal duct to the disappearance and reappearance of spermatozoa induced by temporal cryptorchidism.

Cryptorchid surgery to move the testis and epididymis to the abdomen was performed in mice of 60 days of age; one week later the mice were subjected to further surgery to reposition the organs in the scrotum. The mice were sacrificed at 1 week intervals until 11 weeks after the initial operation. After the first operation, spermatozoa in the epididymal duct rapidly disappeared and were almost absent until the 4th week. Then spermatozoa appeared again, increased, and reached normal numbers by 10 weeks. With the disappearance of the spermatozoa, a PAS-positive material, which is believed to be secreted in the middle part of the head of the epididymal duct (ABE et al., 1982), was accumulated in the epididymal duct in the body and tail of the epididymis, and PAS-positive inclusions appeared in the principal cells of the duct in the body 2 weeks after the first operation. The inclusions developed in size and number during the aspermia period, then decreased in number with the reappearance of spermatozoa from the 5th week to ultimately disappear by 10 weeks after the first operation. We have previously demonstrated that such inclusions appear also after efferent duct ligation, which interrupts the flow of spermatozoa and testicular fluid into the epididymal duct (ABE et al., 1982). Both present and previous findings indicate that the appearance of PAS-positive inclusions depends on the absence of spermatozoa in the epididymal duct irrespective of the presence of the testicular fluid in the duct. It is suggested that the PAS-positive material is utilized by spermatozoa and, in the absence of spermatozoa, is accumulated in the lumen and ingested by the principal cells of the epididymal duct in the body of the epididymis.

Considerations in selecting a postvasectomy semen examination regimen.

The criteria for declaring a vasectomized man sterile have been the subject of debate for many years, yet most suggested regimens differ. The problem lies in the remaining unanswered physiologic questions of such a fundamental nature as to frustrate attempts to formulate a regimen based strictly on medical considerations. The rates of disappearance of sperm following vasectomy vary considerably among men. The physiologic basis for these variations are herein discussed for the first time. At present, regimens reflect, for the most part, social considerations, according to the values and perceptions of the individual physician. The problems raised by postvasectomy residual sperm and current formulation of regimens are described.

Effects of CA on the epididymis of intact, castrated and TP-treated langurs (Presbytis entellus entellus Dufresne).

Cyproterone acetate (CA) treatment of intact langurs resulted in the disappearance of spermatozoa and regression of epididymal lumen, which can be compared with castration. The antiandrogenic nature of CA was confirmed in castrates treated simultaneously with testosterone propionate.

Changes in luminal plasma and disappearance of spermatozoa from the ligated cauda epididymidis of the androgen-deficient rabbit.

By 3 weeks after castration the majority of spermatozoa in the ligated cauda epididymidis were dead and decapitated and there was a 46% reduction in the total number of spermatozoa. By 5 weeks after castration > 99% of spermatozoa had disappeared. Electrophoresis of cauda epididymal plasma (CEP) on polyacrylamide gels revealed that after castration the protein composition of CEP changed from a pattern specific to the epididymis to one similar to blood serum. These changes in the luminal content could be prevented by administering testosterone. When spermatoza from the cauda epididymidis were diluted in CEP from normal rabbits they remained motile for several hours at room temperature. Dilution in CEP from 3- ro 5-week castrated animals stimulated vigorous forward motility but this declined to very low levels after 40 min. The evidence indicates that dead spermatozoa can be removed from the epididymis after castration by mechanisms not involving granuloma formation.

Disappearance of spermatozoa from ejaculate after vasectomy.

A follow up study was conducted among 624 men who underwent vasectomy at the Margaret Pyke Centre in London from July 1971 to October 1972 to determine the time required for them to become azoospermic. Age of the men frequency of ejaculation and time elapsed since the operation were charted against each other. Men aged 20-39 cleared spermatozoa from their ejaculate in a similar fashion; older men cleared more slowly. This difference in clearance rates was significant at all times after 6 months. For men in the 20-39 age group clearance rates were similar regardless of coital frequency; older men cleared faster with higher coital frequency rates. Coital frequency of more than 3 times weekly was associated with rapid clearance. It is possible that postvasectomy sterility may be achieved sooner than azoospermia.

Fate of spermatozoa in the male: II. Absence of a specific sperm disposal mechanism in the androgen-deficient hamster and rabbit.

This study provides no support for previous conclusions that castration is followed by rapid destruction and disappearance of spermatozoa retained within the cauda epididymidis. Even 28 days after castration, there was no significant difference as compared with controls in the number of spermatozoa remaining within the ligated duct, providing that the duct epithelium remained intact. The significant reduction in sperm numbers which occurred in some castrate animals was invariably associated with rupture of the duct; this usually developed close to a ligature with formation of a sperm-filled granuloma or with extravasation of spermatozoa found in peritubular fibrinoid deposits. This and their phagocytosis after escape from the duct accounts for the rapid disappearance of spermatozoa from the ligated cauda epididymidis of castrated hamsters and rabbits. A state of androgen deficiency does not elicit special mechanisms for intraluminal sperm disposal involving either lysis or their ingestion by cells of the intact epithelium.