Maytê Koch Balarini

Morphometry of testis and seminiferous tubules of the adult crab-eating fox (Cerdocyon thous, Linnaeus, 1766)

Body and testicular biometric parameters are very important for establishing reproductive patterns and, consequently, the development of protocols for assisted reproduction in different species. A direct correlation between the testis weight and the sperm population was observed in other studied species, because the testis size primarily reflects the total volume of the seminiferous tubule, its main component. The objective of this study was to determine the testicular volume parameters and correlate data from morphometry of testis and seminiferous tubules with body mass in six adult crab-eating foxes. The mean body weight of the crab-eating foxes in this study was 6.53 kg, with approximately 0.068% allocated to the testicular mass and 0.042% specifically to seminiferous tubules, which represented 87.5% of the testicular parenchyma. The albuginea comprised 12.5% of the testicular mass. The mean diameter of seminiferous tubules was 236 μm, and the mean thickness of the seminiferous epithelium was 62.9 μm. Values of tubular parameters indicate a sperm productivity close to those observed in previously studied carnivores.

Stages and duration of the seminiferous epithelium cycle in the bat Sturnira lilium

Knowledge of the stages that compose the seminiferous epithelium cycle (SEC) and determination of the duration of spermatogenic processes are fundamental for the accurate quantification of the dynamics of spermatogenesis. The aim of this study was to characterize the stages that compose the SEC of the bat Sturnira lilium, including evaluation of the average frequency of each of these stages throughout the year and calculation of the duration of the spermatogenic process. An ultrastructural characterization of the formation of the acrosomal cap was also performed. Testicular fragments were processed for morphological and immunohistochemical analysis as well as ultrastructural analysis using transmission electron microscopy. According to the tubular morphology method, the SEC in S. lilium is divided into eight stages, following the pattern found in other mammals. Primary spermatocytes were found at zygotene in stage 1 of the cycle. There was no variation in frequency of each of the stages over the seasons, with stage 1 being the most frequent, and stage 7 the least frequent. The duration of one seminiferous epithelium cycle was 3.45 days, and approximately 15.52 days were required for the development of sperm from spermatogonia. Ultrastructural characterization allowed the formation of the acrosomal cap in round spermatids to be monitored. In conclusion, the stages that compose the SEC in S. lilium are generally similar to those described for other mammals, but the duration of the spermatogenic process is shorter than previously recorded for mammals. The presence of primary spermatocytes at zygotene in stage 1 of the cycle is probably due to the longer duration of this stage.

Stages and duration of the cycle of the seminiferous epithelium in oncilla (Leopardus tigrinus, Schreber, 1775)

Six adult Leopardus tigrinus (oncilla) were studied to characterize stages of the seminiferous epithelium cycle and its relative frequency and duration, as well as morphometric parameters of the testes. Testicular fragments were obtained (incisional biopsy), embedded (glycol methacrylate), and histologic sections examined with light microscopy. The cycle of the seminiferous epithelium was categorized into eight stages (based on the tubular morphology method). The duration of one seminiferous epithelium cycle was 9.19 d, and approximately 41.37 d were required for development of sperm from spermatogonia. On average, diameter of the seminiferous tubules was 228.29 μm, epithelium height was 78.86 μm, and there were 16.99 m of testicular tubules per gram of testis. Body weight averaged 2.589 kg, of which 0.06 and 0.04% were attributed to the testis and seminiferous tubules, respectively. In conclusion, there were eight distinct stages in the seminiferous epithelium, the length of the seminiferous epithelium cycle was close to that in domestic cats and cougars, and testicular and somatic indexes were similar to those of other carnivores of similar size.

The tubular compartment and the spermatogenic dynamics of the wild rodent Oxymycterus nasutus (Rodentia: Cricetidae)

Despite the order Rodentia present worldwide distribution and large number of species in the Brazilian fauna, detailed studies on testicular morphophysiology are still scarce. Therefore, this study aimed to analyze the dynamics of the spermatogenic process of Oxymycterus nasutus using morphometrical and stereological tools. Testicles from ten sexually mature males were used, showing a gonadosomatic index of 0.89%. The testicular parenchyma showed one of the highest tubulesomatic indexes reported among wild rodents - 0.82% - from which 65.12% was allocated into seminiferous epithelium. The average tubular diameter was 249.89 μm, whereas the epithelium height was 62.47 μm and the total length was 18.62 m per gram of testis. Eight different stages of the seminiferous epithelium cycle were described. Stage 1 was used for counting the germ cell population as well as the Sertoli cells. On average, 3.47 type-A spermatogonia, 24.39 primary spermatocytes in preleptotene/leptotene, 24.13 primary spermatocytes in pachytene, 68.38 round spermatids and 7.33 Sertoli cells were found per tubular cross section. There were 91.02 × 10(6) Sertoli cells per gram of testis and each cell was able to support 9.33 spermatids and 16.43 germ cells. The coefficient of spermatogonial mitosis was 7.02, while 2.83 spermatids were produced for each primary spermatocyte in pachytene. The overall efficiency of spermatogenesis was 19.70 cells, whereas the sperm reserve per gram of testis totalized 849.63 × 10(6) spermatids. Therefore, the presented data showed that O. nasutus shows a high energetic investment in reproduction, corroborating the findings for other species of the Cricetidae family.

Organization and quantification of the elements in the intertubular space in the adult jaguar testis (Panthera onca, LINNAEUS, 1758).

The endocrine portion of mammal testicle is represented by Leydig cells which, together with connective cells, leukocytes, blood and lymphatic vessels, form the intertubular space. The arrangement and proportion of these components vary in the different species of mammals and form mechanisms that keep the testosterone level--the main product of the Leydig cell--two to three times higher in the interstitial fluid than in the testicular blood vessels and 40-250 times higher in these than in the peripheral blood. Marked differences are observed among animal species regarding the abundance of Leydig cells, loose connective tissue, development degree and location of the lymphatic vessels and their topographical relationship with seminiferous tubules. In the jaguar about 13% of the testicular parenchyma is occupied by Leydig cells, 8.3% by connective tissue and 0.3% by lymphatic vessels. Although included in standard II, as described in the literature, concerning the arrangement of the intertubular space, the jaguar has grouped lymphatic vessels in the intertubular space instead of isolated ones. In the jaguar the average volume of the Leydig cell was 2386 microm3 and its average nuclear diameter was 7.7 microm. A great quantity of 2.3 microm diameter lipidic drops was observed in the Leydig cell cytoplasm of the jaguar. The Leydig cells in the jaguar occupy an average 0.0036% of the body weight and the average number per gram of testicle was within the range for most mammals: between 20 and 40 million.

Microscopia e morfometria de componentes tubulares de testículos de coelhos suplementados com geleia real

This study aimed to investigate the effects of royal jelly on spermatogenesis in rabbits treated with different concentrations of RJ (Control; 0,5mg/day; and 1,0mg/day) using testicular morphometry. There was no significant difference between the body weight (T1= 3.20±0.19kg; T2= 2.96±0.30kg; T3=3.21±0.37kg) and gonadal weight (T1= 2.36±0.33g; T2= 2.53±0.33g; T3= 2.64±0.39g), gonadossomatic index (T1= 0.15±0.02%; T2= 0.17±0.03%. T3= 0.16±0.02%) and tubulossomatic index (T1= 0.06±0.01%; T2= 0.07±0.01%. T3= 0.06±0.01%) between treatments, showing that the percentage of body mass, and the percentage of seminiferous tubules allocated in testis were similar in the 3 experimental groups. Similarly, the mean diameter of the seminiferous tubules (T1= 225.95±13.27µm; T2=239.68±21.50µm; T3= 231.57±15,94µm), the height of the seminiferous epithelium (T1=66,05±5,37µm; T2=73.47±9.11µm; T3=63.34±4.79 µm) and length of seminiferous tubule for testis (T1=46.63±13.44m; T2=43.58±12.17m; T3=46.96±9.54m) and per gram of testis (T1=19.50±2.68m; T2=17.12±3.91m; T3=17.78±1.98m) did not differ statistically. It was concluded that supplementation with royal jelly, at the doses used, did not alter the testicular parameters evaluated here.

Germ cells and the seminiferous epithelium cycle in the wild rodent Oxymycterus rufus (Rodentia: Cricetidae)

Oxymycterus rufus is a wild rodent that inhabits one of the world hotspots known as the Atlantic Rain Forest in Brazil. Due to the lack of reproductive data regarding such species, the present study aimed to describe O. rufus spermatogenic process through morphometrical and stereological analyses. To do so, testicular fragments of five sexually mature males were routinely processed for light and transmission electron microscopy. The results showed that each seminiferous epithelium cycle corresponded to 6.58 days, while the entire spermatogenic process lasted 29.61 days. The coefficient of spermatogonial mitoses was 5.64 and 2.79 spermatids were produced from each primary spermatocyte in pachytene. The spermatogenesis yield was 11.98 cells. The Sertoli cell index was 4.29, while its overall support capacity was 8.21 cells. The testicular sperm reserve was 183.5 x 10 6 cells, while 962.00 x 10 6 spermatids were found per gram of testis. The daily sperm production per testis and per gram of testis was 28.56 x 10 6 and 73.13 x 10 6 sperm, respectively. Therefore, the short duration of the seminiferous epithelium cycle along with rapid production of sperm indicates that O. rufus shows high efficiency in spermatogenesis.