Search

Psychological stress is now widely recognized as one of the major risk factors for male fertility. Its impact on the dynamics of testicular germ cells, however, has yet to be fully investigated. Therefore, we used the rat restraint stress (RS) model as a psychological stressor to assess the impact of psychological stress on testicular germ cell dynamics. Adult male SD rats were exposed to sub-chronic RS for 1.5 and 3 h per day for 30 days. The quality of cauda epididymis spermatozoa was adversely affected by RS exposure, and the frequency of spermatozoa with tail abnormalities was higher than that of spermatozoa with head abnormalities. RS exposure adversely affected testicular daily sperm production by disturbing the meiotic and post meiotic germ cell kinetics in the testis. The histomorphology of the testis was altered by loosening and vacuolization in the seminiferous epithelium, germ cell exfoliation and the presence of giant cells. Seminiferous tubules of stage I-VI and VII-VIII were severely affected in rats exposed to RS for 3 h. By interfering with steroidogenic enzymes, RS exposure disrupts testosterone biosynthesis. The testicular oxidative balance was also disturbed by RS exposure, which disrupted the levels/activities of lipid peroxidation, Nrf-2, superoxide dismutase and catalase. There was also an increase in caspase-3 activity and a decrease in the Bax-Bcl2 ratio. In conclusion, our findings suggest that psychological stressors like RS impair testicular functions in rats by disrupting germ cell dynamics, downregulating testicular androgenesis and increasing oxidative stress and apoptosis., (© 2022 Wiley-VCH GmbH.)

In an earlier study we have demonstrated reproductive-stage dependent, cell specific existence of inducible nitric oxide synthase (iNOS) and neuronal nitric oxide synthase (nNOS)/NO system in testis of the catfish, Clarias batrachus. The present study is an extension to examine the role of NO in steroidogenesis and spermatogenesis through in vivo administration of a NO donor, sodium nitroprusside (SNP) and a NOS inhibitor, N-nitro-l-arginine methyl ester (l-NAME) during the quiescence and recrudescence phase of the reproductive cycle of the catfish. Effects of these chemicals were assessed on the gonadosomatic index (GSI), levels of circulating & testicular testosterone, NO, activities of 3β-hydroxysteroid dehydrogenase (3β-HSD), 17β-hydroxysteroid dehydrogenase (17β-HSD) in testis, expression of different NOS isoforms and testicular morphology in relation to spermatogenesis. SNP treatment increased the GSI, testicular and circulating testosterone & NO, activities of testicular 3β-HSD & 17β-HSD, and expression of NOS isoforms. It also increased the area and perimeters of interstitium and seminiferous tubules in the testis. It accelerated the spermatogenesis, as was evident from the large number of spermatids/spermatozoa in seminiferous tubules and very few spermatogonial cells/primary spermatocytes in comparison to the control testis. On the contrary, l-NAME significantly suppressed GSI, testosterone & NO levels in serum and testis, and activities of testicular 3β-HSD & 17β-HSD. It also suppressed the expression of NOSs in testis. Though l-NAME did not alter the spermatogonial mitotic proliferation with the advancement of testicular recrudescence, it halted the progression of spermatogenesis (meiotic division and spermatozoa formation) as was clear from the increase in spermatogonial cells and very few advanced germ cells in the seminiferous tubules in l-NAME treated testis, compared to the control testis. The above noted effects were highly pronounced in the recrudescing catfish. Their effects were very marginal and at a particular dose levels of SNP and l-NAME in the quiescent testis. This study distinctly provides evidence of pro-steroidogenic and pro-spermatogenic role of NO. This study also demonstrates the existence of eNOS in fish testis for the first time. The positive feedback control of expression of all isoform of NOS in testis by NO is also noteworthy., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Asprosin is an orexigenic adipokine that regulates appetite and glucose homeostasis in mammals. To date, only fragmentary findings are reported regarding its role in testicular activities. In the current investigation, immunolocalization and direct action of asprosin in adult mice testis was evaluated. Immunohistochemical and immunoblot studies were performed to analyse the testicular expression of asprosin. Intratesticular treatment of asprosin (0.1 μg and 1.0 μg per testis) was given to evaluate its direct action on testicular functions. Sertoli and Leydig cells were found to be immuno‐positive for asprosin. Intratesticular administration of asprosin resulted into a significant increase in glucose and lactate levels along with enhanced expression of asprosin receptor OLFR734, insulin receptor (IR), glucose transporter 8 (GLUT 8), lactate dehydrogenase (LDH) activity and monocorboxylate transporters (MCT2 and 4). In addition, asprosin administration increased the testicular expression of cell proliferation (proliferating cell nuclear antigen: PCNA), cell survival (B cell lymphoma 2: Bcl2) and decreased germ cell apoptosis (Cysteine aspartic acid protease 3: Caspase 3) leading to increased sperm counts. Further, asprosin treatment resulted into increased level of total cholesterol, testosterone and steroidogenic markers (steroidogenic acute regulatory protein: StAR; 3beta‐hydroxysteroid dehydrogenases: 3β HSD and 17beta‐hydroxysteroid dehydrogenases: 17β HSD). Asprosin treatment promotes testicular glucose uptake and lactate synthesis to provide energy for steroidogenesis and spermatogenesis. The significant correlation between the asprosin‐induced increased IR expression and increased testosterone, glucose and lactate levels suggests its role in increased survival and proliferation but decrease in germ cell apoptosis. This study proposed asprosin's role as an autocrine/paracrine regulator of testicular functions in adult mice. [ABSTRACT FROM AUTHOR]

The present study demonstrates seasonal variation in the cellular expression of neuropeptide Y (NPY), a known orexigenic neuropeptide, in the testis of the catfish, Clarias batrachus and its relation with testicular steroids. In vitro effects of NPY on androgen production and activities of steroidogenic enzymes were also analyzed to reaffirm the relation between NPY and steroids. NPY-immunoprecipitation was observed in Sertoli cells, interstitial cells and germ cells in recrudescing testis. Intensity of NPY-immunoreaction in the interstitial cells increased steadily with initiation of spermatogenesis and reached maximal in fully grown testes, and then decreased suddenly in the spermiating/spent testis. NPY was also expressed considerably in Sertoli cells in recrudescing testis, but disappeared in the fully grown testis. A moderate NPY-immunoreactivity was also seen in spermatogonial cells in recrudescing testis, but intense NPY-immunoprecipitation was detected in advanced germ cells (spermatids/spermatozoa) in fully mature testis. NPY-immunoreation intensity in interstitial cells showed positive correlation with increasing levels of testicular testosterone and 11-ketotestosterone, and with activities of 3β-HSD & 17β-HSD coinciding with advancing testicular activities. NPY treatment of testicular fragments in vitro stimulated the activities of 3β-HSD & 17β-HSD and increased testosterone & 11-ketotestosterone levels. This study for the first time demonstrates the existence of NPY peptide at cellular levels in fish testis, which stimulates androgen production by acting directly at testicular level. [ABSTRACT FROM AUTHOR]

Considering the absence of information on testicular growth factors in fishes, present study was aimed to elucidate the existence of BMP15, an important member of TGF-β superfamily, in the testis of a seasonally breeding freshwater catfish, Clarias batrachus and its role in regulation of testicular activities. The study demonstrated the expression of BMP15 in the somatic cells (Sertoli and interstitial cells) in fish testis. The expression varied with changing testicular activity; the expression was very high in the quiescent and early recrudescing testis coinciding with the renewal of spermatogonial cells. Expression then declined gradually with progression of spermatogenesis and steroidogenesis. Expression of BMP15 showed positive correlation with seasonally changing testicular 17β-estradiol but negatively with testicular testosterone and 11-ketotestosterone. In vitro treatment of testis with recombinant human BMP15 enhanced the production of estradiol-17β but concurrently suppressed the production of testosterone and 11-ketotestosterone in testis. Though BMP15 did not alter the expression of StAR protein in the testis, it promoted the expression of 3β-hydroxysteroid dehydrogenase and aromatase in fish testis. Thus the present study for the first time demonstrates that fish testis is capable of producing BMP15 and is expressed by the somatic cells unlike mammals wherein it is produced exclusively by germ cells. Study also suggests that BMP15 may modulate the testicular steroidogenesis by altering the expression of steroidogenic enzymes. BMP15 also appears to play crucial role in renewal of spermatogial cells by augmenting the testicular production of 17β-estradiol. [ABSTRACT FROM AUTHOR]

• Kiss1 expresses in the theca and granulosa cells of ovarian oocyte and interstitial cells in testis of Clarias batrachus. • Kisspeptin receptor antagonist (p234) treatment decreases production of 17β-estradiol in ovary and testosterone in testis. • The p234 decreases the activities of 3β-hydroxysteroid dehydrogenase and 17β-hydroxysteroid dehydrogenase. • The p234 treatment halts the progression of oogenesis. • The p234 arrests the testicular growth and spermatogenesis. The central role of kisspeptin (kiss) in mammalian reproduction is well established; however, its intra-gonadal role is poorly addressed. Moreover, studies investigating intra-gonadal role of kiss in fish reproduction are scanty, contradictory and inconclusive. The expression of kiss1 mRNA has been detected in the fish brain, and functionally attributed to the regulation of reproduction, feeding and behavior. The kiss1 mRNA has also been demonstrated in tissues other than the brain in some studies, but its cellular distribution and role at the tissue level have not been adequately addressed in fish. Therefore, an attempt was made in the present study to localize kiss1 in gonadal cells of the freshwater catfish, Clarias batrachus. This study reports the presence of kiss1 in the theca cells and granulosa cells of the ovarian oocytes and interstitial cells in the testis of the catfish. The role of kiss1 in the ovary and testis of the catfish was also investigated using kiss1 receptor (kiss1r) antagonist (p234). The p234 treatment decreased the production of 17β-estradiol in ovary and testosterone in the testis by lowering the activities of 3β-hydroxysteroid dehydrogenase and 17β-hydroxysteroid dehydrogenase under both, in vivo as well as in vitro conditions. The p234 treatment also arrested the progression of oogenesis, as evident from the low number of advancing/advanced oocytes in the treated ovary in comparison to the control ovary. It also reduced the area and perimeter of the seminiferous tubules in the treated catfish testis. Thus, our findings suggest that kiss is involved in the regulation of gonadal steroidogenesis, independent of known endocrine/ autocrine/ paracine regulators, and thereby it accelerates gametogenic processes in the freshwater catfish. [ABSTRACT FROM AUTHOR]

Highlights: [•] Somatic as well as reproductive actions of GH is temperature dependent in the catfish, Clarias batrachus. [•] GH stimulates spermatogonial proliferation and accelerates spermatogenic processes. [•] GH promotes testosterone and estradiol production in the catfish. [•] Reproductive action of GH action is mediated through IGF-I in the catfish. [Copyright &y& Elsevier]