Anatomical aspects of the male reproductive system in the bonnet monkey (Macaca radiata)

Observations on the anatomy of the funiculus spermaticus and the testis in Brachyteles sp. (SPIX, 1823) primates - Atelidae

BACKGROUND

Analysing the literature about the reproductive anatomy on New World Primates, one can see the need of standardisation on the description methods and, more importantly, the lack of detailed information. The problem is aggravated by the difficult access to specimens of the endangered species such as Brachyteles sp. This paper's objective was to extend knowledge on the male reproductive anatomy of these primates. The testis and funiculus spermaticus of Brachyteles are described in detail.

METHODS

We utilised one individual of Brachyteles arachnoides, two hybrids (B. arachnoides × Brachyteles hypoxanthus) and photographs of the testis of a third fresh specimen of a hybrid individual.

RESULTS

The septum formed by tunica dartos adheres to the testis and separates the scrotum in two testicular cavities. Passed the spermatic cord, the external spermatic fascia continues with the tunica dartos, covering the cranial half of the testis. The fascia cremasterica divides itself in bundles of fibres and forms loops around the testicles creating a sac like structure that seems to be unique among Neotropical Primates. The appendix testis is described for the first time in platyrrhini. It is presented as a sessile structure in the extremitas capitata of the testis. Previous literature on the reproductive anatomy of platyrrhini is limited. Despite that, it can be said that the large size and volume of the testis, and complex structure of the cremaster, could consist of a heat loss reduction strategy in cold and humid forest environments.

CONCLUSIONS

Except for the larger size of the testicles in hybrid individuals, no other significant morphological differences were found between B. arachnoides and hybrids (B. arachnoides × B. hypoxanthus).

Impact of Seminal Plasma Composition on Sperm Freezability in Wild Mammals: A Review

This review was designed to summarize the most important information around seminal plasma composition and discuss its impact on the freezability of wild mammal semen samples. Seminal plasma is made up of various biochemical constituents, including ions, lipids, proteins, enzymes, and sugars, which vary between species in response to the presence and size of any relevant accessory glands. The biochemical constituents of seminal plasma may change as a result of age, individual variability, and seasonality. These constituents are responsible for supporting different functions in sperm cells, contributing to motility, acrosomal reaction, and fertilization events. A detailed understanding of seminal plasma biochemistry may help to optimize semen freezing protocols, enabling the dynamic alteration in diluents to allow for increased sperm viability rates after thawing.

Morphological description of male genital organs of Marca's marmoset (Mico marcai)

Morphological characterisation of the genital organs of primates may bring significant contributions to the understanding of different reproductive behaviours and support new conservation strategies. However, relevant or detailed descriptions of genital morphology of several primate species are still lacking. This study describes the gross and microscopic anatomy of the internal and external genitalia of Marca's marmoset (Mico marcai). The same organs described in other primate species were identified here, but some anatomical particularities were detected, such as absence of a dartos tunic, presence of a vas deferens ampulla, absence of spongious erectile tissue in the pelvic urethra, separation of prostate gland lobes by a longitudinal sulcus and lack of septation in the corpus cavernosus and spongiosus at the level of the shaft and free portion of the penis. Keratinised type 1 spicules arising from epidermal or dermal projections were found in the free portion of the penis. Microscopic analysis revealed a small bone (baculum) consisting of peripheral compact bone and a central, non-ossified area filled with vascular tissue at the distal end of this portion of the penis. Results of this study may support further comparative studies of primates' reproductive ecology.

Long-term study of vasectomy in Macaca radiata--histological and ultrasonographic analysis of testis and duct system

This study was aimed to investigate the long-term effect of vasectomy using the bonnet monkey (Macaca radiata) as a primate animal model. Animals weighing around 6 to 8 kg were randomly chosen for bilateral, unilateral vasectomy and sham-control. The postoperative periods of six months and two years were considered as short and long-term, respectively. Sperm were collected and subjected to analysis before euthanasia. The testes and epididymides were excised from euthanized animals then embedded in paraffin. Normal histological changes were observed in sham-operated animals and short-term contralateral testes. In contrast, marked alterations were observed in the testes and epididymides of both short and long-term groups. Seminiferous epithelium was thinned out showing marked depletion of germ cells in long-term; only a thin layer of Sertoli cells, spermatogonia, and fewer spermatocytes were seen. Exfoliation of germ cells and the occurrence of multinucleated giant cells were common features in these tubules. The epididymal tubular lumens were greatly dilated with accumulated spermatozoa in short and long-term animals; significant defects were observed in the epithelium of the long-term animals. Microscopic spermatic granulomas were noticed in epididymides and the vas deferens. Large granulomas were seen in long-term vasectomized monkeys, frequently compressing the surrounding structures. These granulomas could be visualized in ultrasound, however, only at the late stage of its occurrence. Sperm collected from the unilateral vasectomized animals showed a poor motility score in the capillary mucus penetration test (CMPT). Results indicate that the changes observed after vasectomy might be due to pressure initially, whereas in the long-term the damage was supplemented by autoimmune attack. With immunoglobulin (IgG) deposition in contra-lateral unoperated testis of unilateral vasectomized animals it also showed degenerative changes and a concomitant drop in sperm quality. Although, granulomatous reactions were observed in the epididymis and vas deferens but testes were spared from such reactions even in the long-term.

Impact of sperm retrieval [corrected] on testis and epididymis: an experimental study using Wistar albino rats

The aim of this study was to analyze pathophysiological changes after testicular sperm aspiration (TESA) and microsurgical epididymal sperm aspiration (MESA) procedures. Twenty four mature male Wistar albino rats with a proven breeding history, weighing approximately 200-250 gm were used for the study. Animals were randomly divided into four groups (n = 6), i.e., control, sham-control, unilateral TESA, and MESA. Using a 22G needle, the aspiration procedures were done in testis or caudal epididymis. At the end of 60 days of survival, blood samples were collected and processed for antisperm antibody detection by enzyme-linked immunosorbent assay (ELISA). After euthanasia, testes and epididymides were collected and processed for paraffin embedding. Sections were stained with hematoxylin and eosin, and TUNEL technique. Serum antisperm antibody titer significantly increased in TESA (P < 0.001) when compared to MESA. Histomorphometric analysis indicated testicular alterations in TESA and MESA, with significant damage in TESA in both testes (P < 0.001). Following the MESA procedure, ipsilateral caudal and carpus epididymis showed significant alterations (P < 0.001) and no such alterations were seen in the ipsilateral caput and intact contralateral epididymis. TUNEL staining revealed an up-regulation of apoptosis in both contra- and ipsilateral testes of TESA. Needle prick had produced drastic and irreversible alterations in testis of TESA. Ensuing processes of immunological and inflammatory reaction had the potential to disrupt spermatogenesis and increase germ cell apoptosis. However, extrapolating conclusions from the experimental model to the clinic needs to be done cautiously.