羊驼睾丸细胞凋亡及凋亡相关蛋白的定位

本研究旨在观察羊驼睾丸的出生后发育和精子发生过程中的细胞凋亡及凋亡相关蛋白Bcl2和Caspase3 的定位.取材新生、12月龄和24月龄羊驼的睾丸,用TUNEL法检测睾丸发育和精子发生过程的细胞凋亡,用免疫组织化学技术检测凋亡相关蛋白Bcl2和Caspase3在羊驼出生后发育和精子发生过程中的定位.结果显示在新生羊驼睾丸未检测到TUNEL阳性细胞,Caspase3和Bcl2表达于间质细胞,提示在新生期凋亡蛋白参与间质细胞凋亡的调节,为曲精小管的发育提供空间;12月龄羊驼睾丸TUNEL阳性细胞定位于曲精小管中央部分,Caspase3 和Bcl2定位于间质细胞和曲精小管中央生殖细胞,提示在青春期(12月龄)羊驼睾丸,细胞凋亡和凋亡相关蛋白参与曲精小管管腔形成的调节;24月龄羊驼睾丸TUNEL阳性细胞定位于精原细胞、精母细胞和精子细胞,Caspase3 和Bcl2定位于间质细胞和各个发育阶段的生精细胞,Caspase3阳性细胞在精原细胞最高,向精母细胞和精子细胞逐渐减少,Bcl2在精原细胞弱阳性表达,在血睾屏障以内的曲精小管近腔室部分呈弥散性强阳性表达,提示在性成熟(24月龄)羊驼睾丸精子发生过程中,细胞凋亡主要发生于精原细胞和早期精母细胞,Bcl2可能抑制精母细胞之后生殖细胞的凋亡.结果提示在羊驼睾丸出生后发育和精子发生过程中存在细胞凋亡现象;凋亡蛋白Caspase3和Bcl2参与羊驼睾丸发育和精子发生过程中细胞凋亡的调节.     

Pathogenesis of type 1 (European genotype) porcine reproductive and respiratory syndrome virus in male gonads of infected boar

The objective of this study was to determine the pathogenesis of experimental infection with a type 1 porcine reproductive and respiratory syndrome virus (PRRSV) by defining the sites of viral replication and apoptosis in male gonads from infected boars for a period of 21 days after intranasal inoculation. Microscopically, hypospermatogenesis and abundant germ cell depletion and death were observed in the testes. Such germ cell death occurs by apoptosis, as determined by a characteristic histological patterns and evidence of massive DNA fragment detected in situ terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) reaction. PRRSV was detected in the testicular tissue of infected boars only. Viral nucleic acid was localized in spermatogonia, spermatocytes and spermatids but not in the vesicular and bulbourethral gland. In serial sections, PRRSV-positive cells did not co-localized with apoptotic cells. TUNEL-positive apoptotic cells were more numerous than PRRSV-positive cells in testicular sections. The present study demonstrated that type 1 PRRSV infects the spermatogonia and their progeny, and induces apoptosis in these germ cells.     

Apoptosis and proliferation during seasonal testis regression in the brown hare (Lepus europaeus L.)

Testes samples of 52 brown hares (Lepus europaeus L.), sacrificed between July and January, were subjected to immuno histochemical analysis. The terminal deoxynucleotidyl transferase-mediated d'UTP nick end labelling (TUNEL) method was applied to detect apoptosis; and antibodies to proliferating cell nuclear antigen (PCNA) were used to evaluate cell proliferation in the testes. In the seminiferous epithelium, the apoptotic processes were evident from August to early November with maximal values in September. Cell death in germ cells occurs predominantly during the prophase of the first meiotic division. In July, and from mid-November onwards, only the occasional TUNEL-positive cells can be seen. The proliferation of germ cells continues during the testis regression phase. The average number of PCNA-positive cells decreases slightly from September onwards and rises again in mid-November.     

Testicular Structure and Seminal Pathway in the Yellowtail Tetra Astyanax altiparanae (Characiforms: Characidae)

This study aimed to describe testicular and its main ducts structure in the yellowtail tetra Astyanax altiparanae, contributing to the knowledge of the region in which semen is produced, storage and released, focusing mainly on the dynamic of germinal epithelium and Sertoli cells during germ cell maturation. Ten sexually mature male A. altiparanae had their testes processed according to the routine protocols to optical microscopy. Moreover, spermatic ducts and tubular compartment of the testes of three specimens were perfused with vinyl resin for gross anatomy and scanning electron microscopy. Astyanax altiparanae testes are paired organs, separated for most of their extension, joining posteriorly in a spermatic duct formed by a squamous simple epithelium. Seminiferous compartment presents anastomosing tubular type organisation, and spermatogonia spread along its extent. Spermatogenesis is of cystic type, and there is no main testicular duct. Spermatogenesis develops in ‘waves’, from posterior to anterior part of the gonad. Thus, while sperm is storage posteriorly, spermatogenesis keeps maturing germ cells anteriorly, making the germinal epithelium very dynamic, holding Sertoli cells that change their function as a cystic envelope to produce secretions of the seminal fluid and store sperm. Such kind of development is thought to be responsible by the high prolificacy of this species.     

Impact of oxidative stress and supplementation with vitamins E and C on testes morphology in rats

The aim of the study was to verify whether an increased supply of vitamins E and C prevents the detrimental effects of ozone on the testes. The experiment was performed on 5-month-old rats exposed to ozone (0.5 ppm) for 50 days (5 h daily). Simultaneously, the animals were injected with the vitamins in 5-day intervals and at different doses (0.5, 1.5, 4.5, 5 and 15 mg of vitamin E; 0.5, 3, 9, and 50 mg of vitamin C; or both vitamins together, respectively). Gonad sections were PAS stained. In the ozonized males, depletion of germ cells occurred. In the vitamin E groups, the testes were comparable to the controls, excluding the 0.5-mg-dose vitamin E group in which perivascular fibrosis and intertubular hyalinization were observed. In the vitamin C groups, intertubular hyalinization, partial arrested spermatogenesis, and desquamation of the seminiferous epithelium appeared proportional to the vitamin dose. Additionally, premature spermiation was found at a vitamin C dose of 50-mg. In the rats injected with both vitamins, hyalinization and fibrosis appeared in addition to partial arrest of spermatogenesis and vacuolar degeneration. In conclusion, vitamin E protects against the detrimental effects of ozone in rat testes irrespective of the dose applied. This was not observed for vitamin C. Moreover, administration of higher doses of vitamin C intensified the damage to the testes caused by ozone.     

P-73 Evaluation of the practicality and efficacy of cryotherapy in feline cutaneous squamous cell carcinoma

Facial dermatitis in cats is a poorly understood clinical problem observed in Persian and Himalayan cats. This report describes three cases of idiopathic facial dermatitis in the Persian cat controlled with cyclosporine. The syndrome was observed in a 5-year-old intact female, a 1.5-year-old intact male, and a 3-year-old neutered male Persian cat. The lesions developed over 2 years, 2 months and 18 months, respectively. Cutaneous lesions were mainly localized to the face. A black patchy waxy exudate matted the hair, especially on the chin. Mild crusts and black exudate were also noted on the vulvar folds in one case and on the ventral aspect of the neck in another case. Erythematous, ceruminous otitis was observed in one case. The histopathological findings were exactly the same for all three cases and compatible with idiopathic facial dermatitis of the Persian cat, or eventually an allergic reaction. All cases were managed with cyclosporine (Neoral^® 6–7 mg/kg/day). Lesions were completely controlled after 4–6 weeks. During a 6-month follow-up for two cases, the lesions seemed to be more resistant to therapy. For these two cats, secondary infections with cocci and Malassezia occasionally occurred. No adverse reactions were observed in our three treated cats.
Funding: Self-funded.     

Sites of persistence of feline calicivirus

Various tissues were collected from eight cats persistently infected with feline calicivirus (FCV) strain 255 to determine the sites of viral persistence. Tissues were tested by virus isolation and an immunohistochemical technique in which infected cells were detected in formalin-fixed, paraffin-embedded tissue sections using rabbit antiserum to FCV 255, a biotinylated second antibody and streptavidin-peroxidase. Virus was detected by one or both techniques in tonsillar tissues of each animal, and not in other samples. Infected cells were detected in samples from six of eight kittens, and in each animal were few in number, and were cells of the superficial tonsillar epithelium or the stratum germinativum of the adjacent fossa mucosa. Transmission electron microscopic examination of tissues from three of the cats revealed calicivirus-like particles in cells similar to those identified immunohistochemically. These results confirm that the tonsillar region is the major site of FCV persistence and indicate that virus replication during persistence is confined to the surface epithelium of the tonsil and adjacent fossa mucosa.     

Continual maintenance of the blood-testis barrier during spermatogenesis: the intermediate compartment theory revisited

Tight junctions occur between the lateral processes of neighboring Sertoli cells that divide the seminiferous epithelium into two compartments: basal and adluminal compartments. These tight junctions constitute the blood-testis barrier (BTB). The established theory that the BTB must open when spermatocytes translocate from the basal compartment to the adluminal compartment is marked by one contradiction, that is, normal spermatogenesis occurs in the testis because the BTB is expected to constantly seclude the adluminal compartment from the basal compartment in order to protect haploid germ cells from the autoimmune system. Subsequently, another concept was proposed in which two BTBs divide the seminiferous epithelium into three compartments: basal, intermediate and adluminal compartments. It has been suggested that the transition from the basal region to the adluminal region without the BTB open occurs through the agency of a short-lived intermediate compartment embodying some primary spermatocytes. In contrast, the results of recent findings in the molecular architecture of the BTB suggest that the BTB in the seminiferous epithelium must "open". In this paper, I re-examine the BTBs of boar and experimental cryptorchid mouse testes by transmission electron microscope (TEM). TEM analysis showed that an atypical basal compartment existed in the thin seminiferous epithelium of 14-day post-cryptorchid mice testes. In developmental boar testes, ectoplasmic specialization (ES) of the seminiferous epithelium showed dynamic behavior. The intermediate compartment was clearly observed between the basal and adluminal compartments of the mature boar seminiferous epithelium. ESs were observed between Sertoli cells and spermatids at all developmental stages, including early, late and mature. Furthermore, ESs were situated on the apical surface of the seminiferous epithelium. From these results, I propose that the BTB is continually maintained during spermatogenesis and suggest a model of ES circulation in the seminiferous epithelium.     

Vascularization and Production of Mitogenic Factor(S) in Domestic Cat (Felis catus) Testes: Preliminary Results

Some male seasonal breeders are known to undergo testicular growth and regression throughout the year. The periodic and fast physiological development and regression processes, with simultaneous fast changes in blood flow, appears to be stimulated by angiogenic substances and inhibited by anti-angiogenic factors. The objective of this study was to evaluate the effect of season on microvascularization and production of angiogenic factors by testicular tissue, using the male cat as a model. Monthly, testes were collected post mortem from domestic stray cats, for histology and for tissue culture. Testis explants were cultured for 18h and conditioned media were tested for their ability to stimulate mitogenesis of bovine aortic endothelial cells (BAEC). Vascular endothelial growth factor (VEGF) was used as a positive control. Proliferative response of BAEC to samples was evaluated by determining the number of cells in each well using a Neubauer chamber. Vascular density was assessed by a computerized image analysis ('Scion Image, NIH, USA') based on the total histological area occupied by the vascular lumen. Percentage data subjected to arcsine transformation were analysed by one-way ANOVA and post-comparison tests. There was a significant increase in microvascular areas in November ( P  < 0.001), when compared to the remaining months (LSD test). All cat testicular tissue showed the capability to increase BAEC proliferation, when compared to negative controls, throughout the study. However, there was an increase in BAEC mitogenesis in February ( P  < 0.05) and November ( P  < 0.001), when compared to the other months. Our data show that cat testicular tissue from different periods of the year stimulates angiogenic factor(s). Furthermore, changes in angiogenesis may play a role on vascular growth and regression of the testes during the breeding and non-breeding season in the male cat.     

Vitamin A Deprivation Affects the Progression of the Spermatogenic Wave and Initial Formation of the Blood-testis Barrier,Resulting in Irreversible Testicular Degeneration in Mice

The blood testis-barrier (BTB) is essential for maintaining homeostasis in the seminiferous epithelium. Although many studies have reported that vitamin A (VA) is required for the maintenance of spermatogenesis, the relationships between the BTB, spermatogenesis and VA have not been elucidated. In this study, we analyzed BTB assembly and spermatogenesis in the testes of mice fed the VA-deficient (VAD) diet from the prepubertal period to adulthood. During the prepubertal period, no changes were observed in the initiation and progression of the first spermatogenic wave in mice fed the VAD diet. However, the numbers of preleptotene/leptotene spermatocytes derived from the second spermatogenic wave onwards were decreased, and initial BTB formation was also delayed, as evidenced by the decreased expression of mRNAs encoding BTB components and VA signaling molecules. From 60 days postpartum, mice fed the VAD diet exhibited apoptosis of germ cells, arrest of meiosis, disruption of the BTB, and dramatically decreased testis size. Furthermore, vacuolization and calcification were observed in the seminiferous epithelium of adult mice fed the VAD diet. Re-initiation of spermatogenesis by VA replenishment in adult mice fed the VAD diet rescued BTB assembly after when the second spermatogenic wave initiated from the arrested spermatogonia reached the preleptotene/leptotene spermatocytes. These results suggested that BTB integrity was regulated by VA metabolism with meiotic progression and that the impermeable BTB was required for persistent spermatogenesis rather than meiotic initiation. In conclusion, consumption of the VAD diet led to critical defects in spermatogenesis progression and altered the dynamics of BTB assembly.     

Angiogenesis and Interstitial Pressure in a Rat Tumour Model

Introduction and Aim:  The corpus luteum is one of the most intensely vascularized tissues. Luteal angiogenesis is strictly controlled and blood vessels regress completely within a short period of time. The aim of this study was to investigate vascular dynamics in relation to cellular and molecular mechanisms of luteal angiogenesis and anti-angiogenesis.
Material and Methods:  Endothelial cells of blood vessels in paraffin sections of bovine corpora lutea from different stages were examined by labelling with the lectin Bandeiraea simplicifolia agglutinin I. Angiogenesis was studied by morphometry of the capillaries, and immunolocalization of the angiogenic factor VEGF and VEGF-receptor 2. Presence of apoptotic luteal and endothelial cells was investigated using the TUNEL test and transmission electron microscopy.
Results:  During development of the corpus luteum (day 3–8 of the oestrous cycle) a dense capillary network (8–12% area ratio) is established and maintained until day 17. Early regression (day 18–24) is characterized by a remarkable decrease of capillaries (1% area ratio). In the regressing corpus luteum the number of apoptotic luteal cells is closely correlated ( r  = 0.9) to the number of apoptotic endothelial cells. VEGF is immunolocalized in luteal cells (day 3–17), smooth muscle cells and endothelial cells of arterioles of the regressing corpus luteum. During late luteal regression, a moderate increase of capillaries (2.5% area ratio) is obvious.
Conclusions:  The dynamic changes of the capillarity during development and regression of the cyclic corpus luteum correlate with VEGF and VEGF-R2 activities. In contrary to expectations the late stage of luteal regression is accompanied by angiogenesis. One reason for this phenomenon may be an increase in metabolic activity resulting in re-organization of blood vessels already regressed.     

Sexual Maturation in the Bull

In this review, we describe the process of sexual maturation in the bull calf. The testes of the bull grow relatively slowly until approximately 25 weeks of age and then a rapid phase of growth occurs until puberty, at 37–50 weeks of age. During the early postnatal phase of slower growth of the testis pre-spermatogonia and some spermatogonia are established, adult Leydig cells appear and undifferentiated Sertoli cells are produced. The rapid testicular growth, after 25 weeks of age, consists of marked increases in the diameter and length of the seminiferous tubules, dramatic proliferation and differentiation of germ cells, with mature spermatozoa occurring between 32 and 40 weeks of age. The adult Leydig cell population is largely in place by 30 weeks of age and that of Sertoli cells by 30–40 weeks of age. Serum concentrations of LH increase from 4 to 5 weeks of age, to an early postnatal peak at 12–16 weeks of age, followed by a decline to 25 weeks of age. Serum FSH concentrations are high postnatally, declining to approximately 25 weeks of age. Serum testosterone concentrations increase during the phase of rapid testicular growth. Hypothalamic opioidergic inhibition may abate transiently to allow the early postnatal increase in LH secretion, while testicular androgenic negative feedback probably contributes to the decline in gonadotropin secretion to 25 weeks of age. Several lines of study have led us to suggest that early postnatal gonadotropin secretion is pivotal in initiating the process of sexual maturation in the bull calf.     

Androgen concentration in the blood and spermatogenic function of tom cats during the breeding season

In order to better understand androgen secretion in the tom cat during the breeding season, observations of diurnal changes in peripheral blood testosterone (T) levels, were made and the relation between androgen levels (androstenedione (A), 5 alpha-dihydrotestosterone (DHT). T) in testicular and peripheral vein blood was borne. Histologic examinations of the testis were also performed to investigate spermatogenic function. The 9 tom cats used in these studies were 2-3 years old, weighed 3.5-4.0 kg, and were raised in a room under natural lighting. As a result, diurnal peripheral blood T levels in the tom cat fluctuated greatly according to each individual, but since no definite trend could be identified, secretion was determined to be episodic. Although fairly large differences in the 3 types of androgen were observed in testicular vein blood depending on the individual animal, levels on the left and right were almost equal. Moreover, a correlation was found between the testicular and peripheral vein blood concentrations of the 3 androgens (A: p less than 0.01; DHT: p less than 0.05; T: p less than 0.01). Therefore, secretion of testicular androgen can be inferred by measuring peripheral blood androgen levels. Testicular histological examination revealed active spermatogenesis in all of the cats, and no significant inter individual differences were detected in either seminiferous tubule diameters or any of the various germ cells.     

Serum cobalamin concentrations in healthy cats and cats with non-alimentary tract illness in Australia

Objective   To determine a reference range for serum cobalamin concentration in healthy cats in Australia using a chemiluminescent enzyme immunoassay and to prospectively investigate the prevalence of hypocobalaminaemia in cats with non-alimentary tract disease.
Design   Prospective study measuring serum cobalamin concentrations in clinically healthy cats and cats with non-alimentary tract illness.
Procedure   Blood was collected from 50 clinically healthy cats that were owned by staff and associates of Veterinary Specialist Services or were owned animals presented to Creek Road Cat Clinic for routine vaccination. Blood was collected from 47 cats with non-alimentary tract illness presented at either clinic. Serum cobalamin concentration was determined for each group using a chemiluminescent enzyme immunoassay.
Results   A reference range for Australian cats calculated using the central 95th percentile in the 50 clinically healthy cats was 345 to 3668 pg/mL. Median serum cobalamin concentration in 47 cats with non-alimentary tract illness (1186 pg/mL; range 117–3480) was not significantly different to the median serum cobalamin of the 50 healthy cats (1213 pg/mL, range 311–3688). Using the calculated reference range one sick cat with non-alimentary tract illness had a markedly low serum cobalamin concentration.
Conclusion   Although hypocobalaminaemia is uncommon in sick cats with non-alimentary tract illness in Australia, its occurrence in this study warrants further investigation.     

Persistence of undifferentiated spermatogonia in aged Japanese Black cattle

Aging is a major risk factor for spermatogenesis deterioration. However, the influence of age on spermatogenic stem cells and their progenitors in bulls is largely unknown. Here, we report age-related changes in undifferentiated and differentiating spermatogonia in Japanese Black cattle with nearly constant sperm output, by using spermatogonial markers. The numbers of differentiating spermatogonia and more differentiated spermatogenic cells were significantly decreased in aged bovine testes compared with those in young testes. In contrast, the number of undifferentiated spermatogonia was maintained, and their proliferative activity did not differ significantly between young and aged bovine testes. Although severe calcification was only observed to a small extent in aged testes, fewer Sertoli cells and interstitial fibrosis were observed in noncalcified testicular regions. These results suggest that, even in old bulls with nearly constant sperm output, testicular spermatogenic activity declined whereas undifferentiated spermatogonia numbers were maintained. Thus, we propose that undifferentiated spermatogonia may be resistant to age-related changes in bovine testes. Because undifferentiated spermatogonia may contain stem cell activity, our findings highlight the potential utility of undifferentiated spermatogonia as an agricultural resource to produce spermatozoa beyond the natural bovine lifetime through transplantation and in vitro spermatogenesis in future animal production.     

Safety, pharmacokinetics and use of the novel NK-1 receptor antagonist maropitant (Cerenia) for the prevention of emesis and motion sickness in cats

The present study characterizes the safety, pharmacokinetics, and anti-emetic effects of the selective NK-1 receptor antagonist maropitant in the cat. Safety of maropitant was determined following 15 days of subcutaneous (SC) administration at 0.5–5 mg/kg. Maropitant was well tolerated in cats at doses that exceeded the efficacious anti-emetic dose range of the drug by at least a factor of 10 and adverse clinical signs or pathological safety findings were not noted at any dose.The pharmacokinetics of maropitant in cats were determined following single dose oral (PO), intravenous (IV) and SC administration. Maropitant had a terminal half-life of 13–17 h and a bioavailability of 50 and 117% when administered PO and SC, respectively. Efficacy was determined against emesis induced either by xylazine or by motion. A dosage of 1 mg/kg maropitant administered IV, SC or PO prevented emesis elicited by xylazine. The compound had good oral antiemetic activity and a long (24 h) duration of action. Maropitant (1.0 mg/kg) was highly effective in preventing motion-induced emesis in cats. These studies indicate that the NK-1 receptor antagonist maropitant is well tolerated, safe and has excellent anti-emetic properties in cats.     

Immunohistochemical localization of insulin-like growth factor-I receptor (IGF-IR) in the developing and mature rat testes

It has been suggested that insulin-like growth factor-I (IGF-I) plays an important role in the regulation of spermatogenesis in the testes. Its signal is mediated predominantly by the IGF-I receptor (IGF-IR). Signalling through IGF-IR has been shown to have a potent survival function. IGF-IR, a transmembrane tyrosine kinase, is widely expressed across many cell types. In this study, we demonstrated the distribution of IGF-IR in testes of differently aged rats. Anti-IGF-IR is a rabbit polyclonal antibody raised against a peptide mapping at the carboxy terminus of the IGF-IR of human origin. Testicular specimens were fixed in Bouin's solution and embedded in paraffin. The paraffin-embedded sections were processed for standard immunohistochemistry by the labelled streptavidin-biotin technique. At postnatal day 19, IGF-IR immunoreactivity was seen moderately in spermatogonia, and slightly both in leptotene and zygotene primary spermatocytes. At postnatal day 35, immunoreactivity was seen slightly both in the pachytene primary spermatocytes and Leydig cells. Although there was intense immunoreactivity in the Leydig cells and in the elongated spermatids on days 50 and 70, the intensity of reaction was decreased in the elongated spermatids in the 10th month. Our results suggest that IGF-IR may play significant roles in testicular function and germ cell development.     

Transduction and Transplantation of Spermatogonia into the Testis of Ram Lambs through the Extra-testicular Rete

Spermatogonial transplantation will provide a new way to study spermatogenesis in domestic animals, disseminate male genetics and produce transgenic animals, if efficiency can be improved. We evaluated a 'surgical' method for transplanting donor cells into testes of ram lambs, where the head of the epididymis is reflected, and a catheter introduced into the extra-testicular rete testis. We also tested transduction of ram spermatogonia with a lentiviral (LV) vector as a means to identify permanent colonization, and introduce genes into donor cells. Eight ram lambs, 11- to 13-week olds, were the recipients: in five, spermatogonia were injected into one testis, and the contralateral testis was an un-manipulated control: in two, spermatogonia were injected into one testis and the contralateral was sham-injected: in one, both testes were injected. Six lambs received spermatogonia labelled with a cell-tracking dye and these were collected 1 or 2 weeks after transplantation; three lambs received spermatogonia transduced with a LV vector driving the expression of enhanced Green Fluorescence Protein and these were collected after 2 months. Donor cells were detected by immunohistochemistry in tubules of seven of nine recipient testes. Approximately 22% of tubule cross-sections contained donor cells immediately after transplantation, and 0.2% contained virally transduced cells 2 months after transplantation. The onset of spermatogenesis was delayed, and there were lesions in both injected and sham-injected testes. Despite the effects of the surgery, elongated spermatids were present in one recipient testis 2 months after surgery. The results suggest that, after modifying the surgical and transduction techniques, this approach will be a means to produce good colonization by donor spermatogonia in sheep testes.     

Morphological features of the seminiferous epithelium in cat (Felis catus, L. 1758) testes

The aim of the present study was to assess the changes in the germinal epithelium in cats of different ages. Routine histological staining was applied to perform morphological and stereological examinations. The animals were divided into five groups according to age: under 8 months (n=28), 8-12 months (n=30), 12-36 months (n=33), 3-6 years (n=14) and older than 6 years (n=13). The appearance of the gonads of the males in the first group varied the most. The seminiferous tubules of the youngest cats consisted of a monolayer of supporting cells and a few spermatogonia. No tubular lumina were present, and the diameters of the seminiferous tubules reached 132.5 microm. We noted the typical arrangement of gametogenic cells with a tubule diameter of 191.83 microm in the second group. We observed multilayer germinal epithelia with the most significant production of gametes and a seminiferous tubule diameter of 202.61 microm in the third group. The diameters of the seminiferous tubules of the forth and fifth groups were 193.38 microm and 191.84 microm, respectively. The obtained data revealed that the most intensive morphological diversification of the seminiferous epithelium in cats occurs at about 7-8 months of age. The diameters of seminiferous tubules were highest in the third group of cats, and the activity of spermatogenesis of this group, expressed as the number of sperm per 10 mm(2), was also the most distinctive. The spermatogenesis process was most evident in cats between 12 and 36 months of age, which was also when the sperm concentration was highest per estimated surface.     

2-Bromopropane induced germ cell apoptosis during spermatogenesis in male rat

2-Bromopropane (2-BP) causes testicular toxicity in humans and rats. However, the germ cell degeneration of testicular toxicity by 2-BP has not been understood. 2-BP at doses of 135, 405, and 1,355 mg/kg/day was daily injected subcutaneously into Sprague-Dawley rats for 28 days. At the dose of 1,355 mg/kg/day, 2-BP significantly decreased the weights of body and testes, eipididymis, seminal vesicle, and prostate, as well as daily sperm production. Atrophy of seminiferous tubules accompanied with degeneration of germ cells such as spermatogonia, spermatocytes, and elongated spermatids was observed in the testes of rats exposed to the 405 mg/kg/day and 1,355 mg/kg/day of 2-BP. TUNEL-positive germ cells were appeared in the 405 and 1,355 mg/kg/day of 2-BP-treated groups. In addition, ultrastructure alterations of apoptotic germ cells were observed by the electron microscopy study. Dead elongated spermatids were observed at 1,355 mg/kg/day after 28 days exposure. These results suggest that 2-BP impair spermatogenesis may result from apoptotic germ cell death.