Search Results (6)

Spermatogenesis in passerine birds remains poorly characterized. Previous studies focused on the steps of spermiogenesis, while a detailed staging of the seminiferous epithelium cycle is still lacking for this order. In this study, we provide the first comprehensive histological characterization of spermatogenesis in a model passerine species, the zebra finch. We defined ten distinct steps of spermiogenesis based on acrosomal and nuclear morphology of spermatids in Periodic acid–Schiff-stained histological sections. Using this classification, we further defined seven stages of the seminiferous epithelium, encompassing cytological features associated with the programmed DNA elimination, which is unique to passerines. Our analysis revealed that seminiferous tubules of the zebra finch exhibit a mosaic organization typical of all birds examined so far. However, in this species, most stages were characterized by the presence of spermatids at three developmental steps, in contrast to the one to two steps typical of non-passerine birds. To facilitate future comparative studies, we developed a flowchart for determining the stages of the seminiferous epithelium cycle. This work establishes an essential histological framework for future research in reproductive biology of the zebra finch and other passerine species. Full article

High-fat diets (HFDs) have been found to compromise male fertility, with cholesterol dysregulation being a key factor. Sterol regulatory element-binding protein 2 (SREBP2) is a crucial transcription factor that regulates cholesterol biosynthesis and uptake, playing an essential role in maintaining cholesterol homeostasis in the testes. This study investigated the dynamics of SREBP2 and cholesterol levels during rabbit spermatogenesis under HFD conditions. Our findings reveal that SREBP2 expression fluctuates throughout the seminiferous epithelium cycle. However, HFDs induce stage-specific disruptions in cholesterol balance, leading to sperm with increased membrane cholesterol, a reduced sperm count in semen analysis, impaired motility, abnormal morphology, and decreased functionality. In the control group, SREBP2 expression patterns underscored its critical role in normal spermatogenesis. Interestingly, supplementation with extra virgin olive oil (EVOO) reversed the negative effects of HFD, normalizing SREBP2 expression and cholesterol content, which improved sperm quality. These findings emphasize the importance of stage-specific analysis in understanding how dietary fat impacts male fertility and suggest that EVOO may serve as a potential nutritional intervention to protect reproductive health. Full article

Spermatogenesis takes place in a hypoxic environment, and antioxidant enzymes protect germ and somatic cells from free radical-mediated damage. Expression of the antioxidant enzyme system in the canine testis has not yet been investigated. We hypothesized that the slow-release GnRH superagonist deslorelin 4.7 mg implant, which induces temporary reversible suppression of endocrine and germinative testicular function, would affect the testicular expression of antioxidant enzymes compared to untreated adult and prepubertal dogs. The goal of this study was to investigate and compare gene (by qPCR, in whole-tissue homogenates) and protein expression (by immunohistochemistry) of superoxide dismutase (SOD1, SOD2), catalase (CAT), glutathione peroxidase (GPx1), and glutathione disulfide reductase (GSR) in the testes of untreated adult (CON, n = 7), prepubertal (PRE, n = 8), and deslorelin-treated (DES, n = 5, 16 weeks after implantation) dogs. We found that in DES dogs, the gene expression of SOD1 was significantly (p < 0.05) lower and GPx1 was higher than in CON, and SOD2 was higher than in PRE. Expression of all, except for the SOD2 mRNA, differed between the CON and PRE dogs. Immunohistochemistry showed distinct cell-specific localization and expression patterns for the antioxidant enzymes in each experimental group. Additionally, in the CON animals, cell-specific SOD1, CAT, and GSR expression was dependent on the stage of the seminiferous epithelium cycle. These findings confirm that members of the antioxidant enzyme system are present in normal adult and prepubertal testis as well as in the deslorelin-treated downregulated adult canine testis, and that this local antioxidant system protects developing germ cells and somatic cells from oxidative damage. Different expression patterns of antioxidant enzymes in various germ cell populations and stages of the seminiferous epithelium cycle may indicate differences in their susceptibility to oxidative stress depending on their developmental and maturation stage. The continued presence of the antioxidant enzymes in the testis of DES dogs offers protection to spermatogonia as well as Sertoli and Leydig cells from oxidative stress during temporary infertility, potentially contributing to ensure the reversibility of suppression and the return of normal spermatogenesis and steroidogenesis after the end of deslorelin treatment. Full article

Testicular expression of taste receptor type 1 subunit 3 (T1R3), a sweet/umami taste receptor, has been implicated in spermatogenesis and steroidogenesis in mice. We explored the role of testicular T1R3 in porcine postnatal development using the Congjiang Xiang pig, a rare Chinese miniature pig breed. Based on testicular weights, morphology, and testosterone levels, four key developmental stages were identified in the pig at postnatal days 15–180 (prepuberty: 30 day; early puberty: 60 day; late puberty: 90 day; sexual maturity: 120 day). During development, testicular T1R3 exhibited stage-dependent and cell-specific expression patterns. In particular, T1R3 levels increased significantly from prepuberty to puberty (p < 0.05), and expression remained high until sexual maturity (p < 0.05), similar to results for phospholipase Cβ2 (PLCβ2). The strong expressions of T1R3/PLCβ2 were observed at the cytoplasm of elongating/elongated spermatids and Leydig cells. In the eight-stage cycle of the seminiferous epithelium in pigs, T1R3/PLCβ2 levels were higher in the spermatogenic epithelium at stages II–VI than at the other stages, and the strong expressions were detected in elongating/elongated spermatids and residual bodies. The message RNA (mRNA) levels of taste receptor type 1 subunit 1 (T1R1) in the testis showed a similar trend to levels of T1R3. These data indicate a possible role of T1R3 in the regulation of spermatid differentiation and Leydig cell function. Full article

The past three decades revolutionized the goose industry in the world. China holds the world’s largest goose breeds stock by 95% of the global total. To optimize the goose industry and cope with ever increasing poultry meat and egg demands, there is a dire need to focus on reproduction, as most geese breeds exhibit poor reproductive performance. The present study was conducted with the aim to add a contribution in the goose industry and research by the histological visualizing step wise development of germ cells during spermatogenesis by microscopy and a histological technique. Yangzhou goose is a synthetic breed developed by using local goose germplasm resources of China. It is popular in the Chinese goose industry due to high productivity and adaptability. This research evaluated the steps of spermiogenesis and stages along with morphological changes in the seminiferous epithelium in Yangzhou goose ganders. For the assessment of various stages of the seminiferous epithelium cycle, testis sections were embedded in molten paraffin wax. The initial steps of spermiogenesis were depicted by changes in acrosomic granules, whereas further stages were identified by nuclear morphological changes. Ten steps of spermiogenesis and nine stages of seminiferous epithelium were identified. Four types of spermatogonia Ad, Ap1, Ap2 and B were recognized. The results depicted a clear variation in the diameter of seminiferous tubules (ST), epithelium height (EH), luminal tubular diameter (LD), number of seminiferous tubules per field and the Johnsen score. Microscopy indicated that the stages of seminiferous epithelium were similar to other birds and mammals and the ST diameter, EH, LD and Johnsen score are positively correlated while the number of seminiferous tubules per field is negatively correlated with the ST diameter, EH, LD and Johnsen score. Fertility in Yangzhou ganders can further be improved by visualizing the histological development of germs cells in testis tissues during spermatogenesis after onset of breeding season and maturity. Our results suggest that Yangzhou ganders reach complete sexual maturity at 227 days of age. Full article

The presence of the HGF/Met system in the testicular myoid cells was first discovered by our group. However, the physiological role of this pathway remains poorly understood. We previously reported that HGF increases uPA secretion and TGF-β activation in cultured tubular fragments and that HGF is maximally expressed at Stages VII–VIII of the seminiferous epithelium cycle, when myoid cell contraction occurs. It is well known that the HGF/Met pathway is involved in cytoskeletal remodeling; moreover, the interaction of uPA with its receptor, uPAR, as well as the activation of TGF-β have been reported to be related to the actin cytoskeleton contractility of smooth muscle cells. Herein, we report that HGF induces actin cytoskeleton remodeling in vitro in isolated myoid cells and myoid cell contraction in cultured seminiferous tubules. To better understand these phenomena, we evaluated: (1) the regulation of the uPA machinery in isolated myoid cells after HGF administration; and (2) the effect of uPA or Met inhibition on HGF-treated tubular fragments. Because uPA activates latent TGF-β, the secretion of this factor was also evaluated. We found that both uPA and TGF-β activation increase after HGF administration. In testicular tubular fragments, HGF-induced TGF-β activation and myoid cell contraction are abrogated by uPA or Met inhibitor administration. Full article