Changes in semen quality and morphology of the reproductive tract of the male tammar wallaby parallel seasonal breeding activity in the female

Increasing the Yield and Cryosurvival of Spermatozoa from Rhinoceros Ejaculates Using the Enzyme Papain

Simple Summary

Efficient collection and cryosurvival of semen from threatened wildlife species is key for the success of artificial reproductive technologies (ARTs). The viscous nature of ejaculates often collected from species such as rhinoceros, elephant, hippopotamus and primate, render the majority of spermatozoa collected useless and is therefore wasted. The enzyme papain has been used to reduce the viscosity of camelid semen but has yet to be tested in wildlife species. Therefore, the current study investigated the ability of papain to improve the yield and quality of spermatozoa collected from viscous fractions of the rhinoceros ejaculate during cryopreservation. Papain increased the quantity of useable spermatozoa collected from ejaculates, as well as the motility prior to freezing. It also improved the post-thaw motility, velocity, linearity and straightness of samples compared to spermatozoa frozen from the sperm-rich fraction of the ejaculate. There was no detrimental effect on membrane characteristics or DNA integrity. These results show that treating rhinoceros ejaculates with papain is able to salvage valuable spermatozoa and improve survival post-thaw, ultimately increasing the success of ARTs and creation of biobanks for the maintenance and survival of threatened species.

Abstract

The preservation of rhinoceros semen is vital for captive breeding programs. While successful collection and cryopreservation of rhinoceros semen has been reported, the volume and quality of semen produced is often low due to the high viscosity associated with ejaculates collected via electroejaculation. Reducing semen viscosity would enable access to previously unusable spermatozoa from viscous fractions and could improve quality post-thaw. The enzyme papain successfully reduced the viscosity of camelid semen but has yet to be tested in wildlife species. This study assessed the influence of papain on the in vitro quality of rhinoceros spermatozoa during cryopreservation using advanced semen assessment. In experiment 1, the motility of spermatozoa from the viscous fraction of an ejaculate, either untreated or treated with papain and its inhibitor E-64 prior to cryopreservation, was assessed post-thaw. In experiment 2, spermatozoa from papain-treated viscous fractions were compared to spermatozoa frozen from untreated sperm-rich fractions pre-freeze, as well as after 0, 1.5 and 3 h of incubation post-thaw (37 °C). Papain significantly increased the quantity of spermatozoa collected from ejaculates, as well as the motility prior to freezing. Papain also improved the post-thaw motility, velocity, linearity and straightness of samples compared to sperm-rich samples, with no detriment to sperm viability, lipid membrane disorder, production of ROS or DNA integrity (p < 0.05). Results show the benefit of supplementing rhinoceros spermatozoa with papain prior to cryopreservation on sperm cryosurvival and demonstrates the potential of using papain to improve the success of cryopreservation protocols, not only for the rhinoceros, but also for other wildlife species.

Spermatogenesis in the Roborovski hamster (Phodopus roborovskii) and the Chinese hamster (Cricetulus griseus)

BACKGROUND

Spermatogenesis is an elaborately organized and tightly regulated differentiation process. The spermatogenesis duration is stable within a certain species but highly variable between species of the same family.

OBJECTIVES

In this study, the spermatogenesis duration of the Roborovski hamster was measured for the first time, and the spermatogenesis duration of the Chinese hamster was re-assessed.

MATERIALS AND METHODS

Stage classification and cycle length measurement were carried out by labeling the dividing cells with bromodeoxyuridine and an antibody-based chromogen as well as with the periodic acid-Schiff/hematoxylin stain. Analysis was conducted using reference calculation and linear regression. Morphological measurements completed our set of methods.

RESULTS

The mean duration of one seminiferous epithelium cycle was 8.58 ± 0.34 days (mean ± SEM; Phodopus roborovskii) and 16.59 ± 0.47 days (Cricetulus griseus) based on the reference calculation. Slightly higher results were obtained using linear regression analysis: 9.72 ± 0.41 days for P. roborovskii and 17.64 ± 0.61 days for C. griseus. Additionally, a newly developed exemplary flowchart was proposed for the Roborovski hamster to facilitate spermatogenesis stage classification also in other species. The Chinese hamster presented an unexpectedly high paired epididymides weight of 1.701 ± 0.046 g (mean ± SEM) although having a body weight of only 40.5 ± 0.7 g. However, no significant correlation between the relative epididymis weight and spermatogenesis duration in mammals (Spearman rank correlation: r = -0.119, p = 0.607, n = 21) or rodents could be found (r = 0.045, p = 0.903, n = 11).

CONCLUSION

Our data emphasize the stability of the spermatogenesis duration within species and its remarkable variability between species. Further research is needed to identify the principal mechanisms and selection drivers that are responsible for such stability within species and the variability between species.

The role of the androgen receptor in prostate development and benign prostatic hyperplasia: A review

Benign prostatic hyperplasia (BPH) is a benign enlargement of the prostate in which incidence increases linearly with age, beginning at about 50 years old. BPH is a significant source of morbidity in aging men by causing lower urinary tract symptoms and acute urinary retention. Unfortunately, the etiology of BPH incidence and progression is not clear. This review highlights the role of the androgen receptor (AR) in prostate development and the evidence for its involvement in BPH. The AR is essential for normal prostate development, and individuals with defective AR signaling, such as after castration, do not experience prostate enlargement with age. Furthermore, decreasing dihydrotestosterone availability through therapeutic targeting with 5α-reductase inhibitors diminishes AR activity and results in reduced prostate size and symptoms in some BPH patients. While there is some evidence that AR expression is elevated in certain cellular compartments, how exactly AR is involved in BPH progression has yet to be elucidated. It is possible that AR signaling within stromal cells alters intercellular signaling and a "reawakening" of the embryonic mesenchyme, loss of epithelial AR leads to changes in paracrine signaling interactions, and/or chronic inflammation aids in stromal or epithelial proliferation evident in BPH. Unfortunately, a subset of patients fails to respond to current medical approaches, forcing surgical treatment even though age or associated co-morbidities make surgery less attractive. Fundamentally, new therapeutic approaches to treat BPH are not currently forthcoming, so a more complete molecular understanding of BPH etiology is necessary to identify new treatment options.

Social rank does not affect sperm quality in male African wild dogs (Lycaon pictus)

Sperm banking and AI could benefit endangered African wild dog conservation. However, it is unclear whether their dominance hierarchy causes a decrease in reproductive and sperm quality parameters in subordinate males that typically do not breed. In this study, we investigated the effect of social rank on male reproductive parameters, including faecal androgen and glucocorticoid metabolite concentrations, prostate and testes volume, preputial gland size, semen collection success and sperm quality. Samples were obtained from captive males (prebreeding season: n=12 from four packs; breeding season: n=24 from seven packs) that were classified as alpha (dominant), beta or gamma (subordinates) based on the frequency of dominant versus submissive behaviours. In the prebreeding season, semen was successfully collected from all alpha but only half the subordinate males, with urine contamination (associated with lower rank) significantly reducing total and progressive motility, sperm motility index, normal sperm morphology and acrosome integrity. The breeding season was associated with a significant increase in faecal androgens, prostate and testis volume, as well as progressive motility and the total number of spermatozoa ejaculated. However, with the exception of prostate volume (mean±s.e.m: 12.5±4.5, 7.1±1.0 and 7.3±1.0cm3 in alpha, beta and gamma males respectively; P=0.035), all other reproductive and sperm quality parameters did not differ between males of each social rank. In conclusion, reproductive suppression of subordinate males appears to be behaviourally mediated, because males of all social ranks produce semen of similar quality, making them suitable candidates for sperm banking, particularly during the breeding season when sperm quality improves.

The effects of season and devil facial tumour disease on the reproductive physiology of the male Tasmanian devil (Sarcophilus harrisii)

Devil facial tumour disease (DFTD) is the cause of the rapid decline of wild Tasmanian devils. Female devils are seasonal breeders with births peaking during autumn (i.e. March) but the degree of reproductive seasonality in male devils is unknown. The objective of this study was to examine the potential effects of season and DFTD on reproductive function in male devils (n=55). Testicular (1.90±0.23 g) and epididymal (0.90±0.06 g) weights were maximal during autumn and spring (P<0.05), whereas prostate (3.71±0.74 g) and Cowper's gland (0.68±0.22; 0.52±0.21 g) weights peaked during autumn (P<0.001). The motility of spermatozoa from the cauda epididymides extracted post-mortem was similar (P>0.05) across season and disease state (31.5±13.1% total motility). Testicular and epididymal weights were no different between animals displaying late or early-stage DTFD signs or disease-free animals (P>0.1). The accessory sex glands were larger in late-stage DFTD animals than in animals with early-stage disease signs or which were disease-free (P<0.01) but effects of season on this result can't be excluded. Serum testosterone concentrations peaked during summer (0.25±0.18 ng mL(-1)) but values were not different from the preceding and subsequent seasons (P>0.05), nor influenced by disease stage (P>0.1). Seasonal and DFTD-related changes in serum cortisol concentrations were not evident (P>0.1). Male devil reproduction does not appear to be restricted by season nor inhibited by DFTD.

The effect of pregnant and oestrous females on male testosterone and behaviour in the tammar wallaby

Tammar wallaby females (Macropus eugenii) are seasonally breeding marsupials with a post-partum oestrus after a highly synchronised birth period when testosterone concentrations rise in males. Chemical communication appears to be important for mating, as males show checking behaviour, sniffing the urogenital opening (UGO) and the pouch of females. This study investigates whether the presence of pregnant and oestrous females directly influences testosterone in males and if oestrous odours or secretion from the pouch or UGO are attractive. Concentrations of plasma testosterone were measured in males housed with pregnant and oestrous females during two consecutive cycles in the breeding season, and an artificially induced cycle in the non-breeding season. Males were also tested for their interest in swabs taken from the urogenital opening (UGO) or pouch of oestrous females. Testosterone increased sharply in males in the presence of pregnant and oestrous females during all cycles in both seasons, but there was no change when males were exposed to non-cycling females in lactational or seasonal diapause. Males had no preference for either oestrous or non-oestrous samples taken from the pouch or from the UGO from oestrous females. This study confirms that the increase in plasma testosterone in tammar males can be induced through the presence of pregnant and oestrous females, regardless of season and that the increase began when the females were in late-pregnancy. This confirms that the male's reproductive state is dependent on a signal from females and is not blocked through seasonal effects.

Interleukin 8 and Anti-Chlamydia trachomatis Mucosal IgA as Urogenital Immunologic Markers in Patients with C. trachomatis Prostatic Infection

OBJECTIVE

This study evaluates the role of interleukin 8 (IL-8) and anti-Chlamydia trachomatis (CT) immunoglobulin A (IgA) in total ejaculate (TE) of patients affected by chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) as potential markers in prostatic CT infection.

METHODS

Seventy-eight consecutive patients with a diagnosis of CP/CPPS and CT infection were enrolled; 20 healthy volunteers represented the control group. All subjects underwent microbiologic analysis for common bacteria, yeasts, and viruses in TE, expressed prostatic secretion, and urine samples and molecular analysis for CT identification, anti-CT species-specific IgA, and IL-8 levels. Questionnaires regarding symptoms were given to each subject to determine correlations between clinical and laboratory data.

RESULTS

Thirty-five patients were positive for CT plasmid DNA, but none of the controls were positive. Mucosal IgA was detected in 69.2% of patients and significant levels of IL-8 were detected in 75.6% of them. Significant correlations between IL-8 and mucosal IgA (p<0.001) and between IL-8 levels and symptom score results (p<0.001) were found. IL-8 values strongly correlated with CP/CPPS (p<0.001). Moreover, the patients with higher levels of IL-8 and higher positivity for IgA reported the worst symptoms.

CONCLUSIONS

Our results clearly highlight the role of immune system activation in the pathophysiology of CP/CPPS and that seminal IL-8 and mucosal IgA levels specific to CT antigens appear to be the best immunologic markers of chronic chlamydial prostatitis status.