The Experts below are selected from a list of 252 Experts worldwide ranked by ideXlab platform
David W Miller - One of the best experts on this subject based on the ideXlab platform.
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on the synthesis and secretion of rat Seminiferous Tubule proteins in vivo after ischemia and germ cell loss
Biology of Reproduction, 1997Co-Authors: Terry T Turner, David W MillerAbstract:This study was undertaken to determine whether alterations in Sertoli cell protein synthesis and secretion were important precursors to germ cell loss after ischemic insult to the testis. Ischemia was induced by a 1-h, 720 ° spermatic cord torsion, and this was shown to cause a loss of germ cells over a 15-day period. Seminiferous Tubules were perifused in vivo with [ 35 S]methionine. Lumen fluid (LF) was collected by in vivo micropuncture, and Seminiferous Tubule extract (TE) was collected after Tubule homogenization and centrifugation. Electrophoresis of proteins in these fluids followed by autoradiography of radiolabeled proteins allowed examination of synthesized, i.e., TE, and secreted, i.e., LF proteins. No consistent changes were detected in synthesized or secreted proteins prior to the major loss of germ cells; thus, major changes in the capacity of Sertoli cells for protein assembly and transport are not a preliminary feature of post-ischemia germ cell loss. Changes in specific protein synthesis and secretion were also modest in this in vivo environment after germ cell loss. Overall protein synthesis appeared reduced as loss of germ cells progressed, but one protein whose amino acid sequence confirmed identity with a testis-specific stress protein (hst70) was up-regulated after ischemia and germ cell loss.
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protein synthesis and secretion by the rat Seminiferous Tubule in vivo not affected by experimental varicocele
The Journal of Urology, 1996Co-Authors: Terry T Turner, David W MillerAbstract:AbstractPurpose: Varicocele is associated with testicular dysfunction and male infertility. In vivo protein synthesis and secretion by the Seminiferous Tubules can be studied as an overall assessment of Sertoli cell function. The present experiments were undertaken to determine the effect of experimental left varicocele (ELV) on Seminiferous Tubule protein synthesis and secretion.Materials and Methods: Androgen binding protein (ABP) was determined in native testicular interstitial fluid by radioimmunoassay.35 S-methionine was perifused around Seminiferous Tubules in vivo in testes of control rats and those with 30 day ELV. Interstitial fluid (IF) and lumen fluid (LF) were subsequently collected by micropuncture, and a Tubule extract (TE) was prepared. Proteins in all fluids were subjected to one- and two-dimensional electrophoresis and autoradiography to evaluate the total synthesized proteins (those in TE) as well as the secreted proteins (those in LF).Results: Two-dimensional electrophoresis allowed det...
Terry T Turner - One of the best experts on this subject based on the ideXlab platform.
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on the synthesis and secretion of rat Seminiferous Tubule proteins in vivo after ischemia and germ cell loss
Biology of Reproduction, 1997Co-Authors: Terry T Turner, David W MillerAbstract:This study was undertaken to determine whether alterations in Sertoli cell protein synthesis and secretion were important precursors to germ cell loss after ischemic insult to the testis. Ischemia was induced by a 1-h, 720 ° spermatic cord torsion, and this was shown to cause a loss of germ cells over a 15-day period. Seminiferous Tubules were perifused in vivo with [ 35 S]methionine. Lumen fluid (LF) was collected by in vivo micropuncture, and Seminiferous Tubule extract (TE) was collected after Tubule homogenization and centrifugation. Electrophoresis of proteins in these fluids followed by autoradiography of radiolabeled proteins allowed examination of synthesized, i.e., TE, and secreted, i.e., LF proteins. No consistent changes were detected in synthesized or secreted proteins prior to the major loss of germ cells; thus, major changes in the capacity of Sertoli cells for protein assembly and transport are not a preliminary feature of post-ischemia germ cell loss. Changes in specific protein synthesis and secretion were also modest in this in vivo environment after germ cell loss. Overall protein synthesis appeared reduced as loss of germ cells progressed, but one protein whose amino acid sequence confirmed identity with a testis-specific stress protein (hst70) was up-regulated after ischemia and germ cell loss.
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protein synthesis and secretion by the rat Seminiferous Tubule in vivo not affected by experimental varicocele
The Journal of Urology, 1996Co-Authors: Terry T Turner, David W MillerAbstract:AbstractPurpose: Varicocele is associated with testicular dysfunction and male infertility. In vivo protein synthesis and secretion by the Seminiferous Tubules can be studied as an overall assessment of Sertoli cell function. The present experiments were undertaken to determine the effect of experimental left varicocele (ELV) on Seminiferous Tubule protein synthesis and secretion.Materials and Methods: Androgen binding protein (ABP) was determined in native testicular interstitial fluid by radioimmunoassay.35 S-methionine was perifused around Seminiferous Tubules in vivo in testes of control rats and those with 30 day ELV. Interstitial fluid (IF) and lumen fluid (LF) were subsequently collected by micropuncture, and a Tubule extract (TE) was prepared. Proteins in all fluids were subjected to one- and two-dimensional electrophoresis and autoradiography to evaluate the total synthesized proteins (those in TE) as well as the secreted proteins (those in LF).Results: Two-dimensional electrophoresis allowed det...
Mariehelene Perrard - One of the best experts on this subject based on the ideXlab platform.
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effects of a mixture of low doses of atrazine and benzo a pyrene on the rat Seminiferous epithelium either during or after the establishment of the blood testis barrier in the rat Seminiferous Tubule culture model
Toxicology in Vitro, 2020Co-Authors: Philippe Durand, Antonine Blondet, Guillaume Martin, Diane Carette, Georges Pointis, Mariehelene PerrardAbstract:Abstract Atrazine (ATZ), a widely used agricultural pesticide and benzo[a]pyrene (BaP), a ubiquitous environmental human carcinogen can induce alterations of spermatogenesis. In the present study, we showed first that our Seminiferous Tubule culture model, in bicameral chambers, allowed the settlement of the blood-testis barrier (BTB) in 8-day-old male rat cultures and the differentiation of spermatogonia into round spermatids.The effect of a mixture of 1 μg/L of ATZ and 1 μg/L of BaP was then investigated either during or after the establishment of the BTB by using 8- or 20–22-day-old rats. Cultures were performed over a 3-week period. Our results show that claudin-11 and connexin 43 two proteins of the BTB, were impaired by the mixture which also reduced the number of round spermatids (the direct precursors of spermatozoa), by targeting the middle to late pachytene spermatocytes. These effects were observed in 8- and 20–22-day -old rat Seminiferous Tubule cultures. However, the decrease of the number of round spermatids was faster and more marked in the 8-day- than in the 20–22-day -old rat Seminiferous Tubule cultures. Our study emphasizes the possible influence of the age of an individual on the effect of (a) toxicant(s) on spermatogenesis.
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exposure to low dose bisphenol a impairs meiosis in the rat Seminiferous Tubule culture model a physiotoxicogenomic approach
PLOS ONE, 2014Co-Authors: Gerard Steinmetz, Guillaume Montillet, Mariehelene Perrard, Anderson Loundou, Philippe Durand, Marieroberte Guichaoua, Odette PratAbstract:Background: Bisphenol A (BPA) is one of the most widespread chemicals in the world and is suspected of being responsible for male reproductive impairments. Nevertheless, its molecular mode of action on spermatogenesis is unclear. This work combines physiology and toxicogenomics to identify mechanisms by which BPA affects the timing of meiosis and induces germ-cell abnormalities. Methods: We used a rat Seminiferous Tubule culture model mimicking the in vivo adult rat situation. BPA (1 nM and 10 nM) was added to the culture medium. Transcriptomic and meiotic studies were performed on the same cultures at the same exposure times (days 8, 14, and 21). Transcriptomics was performed using pangenomic rat microarrays. Immunocytochemistry was conducted with an anti-SCP3 antibody. Results: The gene expression analysis showed that the total number of differentially expressed transcripts was time but not dose dependent. We focused on 120 genes directly involved in the first meiotic prophase, sustaining immunocytochemistry. Sixty-two genes were directly involved in pairing and recombination, some of them with high fold changes. Immunocytochemistry indicated alteration of meiotic progression in the presence of BPA, with increased leptotene and decreased diplotene spermatocyte percentages and partial meiotic arrest at the pachytene checkpoint. Morphological abnormalities were observed at all stages of the meiotic prophase. The prevalent abnormalities were total asynapsis and apoptosis. Transcriptomic analysis sustained immunocytological observations. Conclusion: We showed that low doses of BPA alter numerous genes expression, especially those involved in the reproductive system, and severely impair crucial events of the meiotic prophase leading to partial arrest of meiosis in rat Seminiferous Tubule cultures.
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hexavalent chromium at low concentration alters sertoli cell barrier and connexin 43 gap junction but not claudin 11 and n cadherin in the rat Seminiferous Tubule culture model
Chemical Hazards in Industry, 2013Co-Authors: Mariehelene Perrard, Diane Carette, Georges Pointis, Nadia Prisant, Jerome Gilleron, Dominique Segretain, Philippe DurandAbstract:Exposure to toxic metals, specifically those belonging to the nonessential group leads to human health defects and among them reprotoxic effects. The mechanisms by which these metals produce their negative effects on spermatogenesis have not been fully elucidated. By using the Durand's validated Seminiferous Tubule culture model, which mimics the in vivo situation, we recently reported that concentrations of hexavalent chromium, reported in the literature to be closed to that found in the blood circulation of men, increase the number of germ cell cytogenetic abnormalities. Since this metal is also known to affect cellular junctions, the authors investigated, in the present study, its potential influence on the Sertoli cell barrier and on junctional proteins present at this level such as connexin 43, claudin-11 and N-cadherin. Cultured Seminiferous Tubules in bicameral chambers expressed the three junctional proteins and ZO-1 for at least 12 days. Exposure to low concentrations of chromium (10 µg/l) increased the trans-epithelial resistance without major changes of claudin-11 and N-cadherin expressions but strongly delocalized the gap junction protein connexin 43 from the membrane to the cytoplasm of Sertoli cells. The possibility that the hexavalent chromium-induced alteration of connexin 43 indirectly mediates the effect of the toxic metal on the blood-testis barrier dynamic is postulated.
Philippe Durand - One of the best experts on this subject based on the ideXlab platform.
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effects of a mixture of low doses of atrazine and benzo a pyrene on the rat Seminiferous epithelium either during or after the establishment of the blood testis barrier in the rat Seminiferous Tubule culture model
Toxicology in Vitro, 2020Co-Authors: Philippe Durand, Antonine Blondet, Guillaume Martin, Diane Carette, Georges Pointis, Mariehelene PerrardAbstract:Abstract Atrazine (ATZ), a widely used agricultural pesticide and benzo[a]pyrene (BaP), a ubiquitous environmental human carcinogen can induce alterations of spermatogenesis. In the present study, we showed first that our Seminiferous Tubule culture model, in bicameral chambers, allowed the settlement of the blood-testis barrier (BTB) in 8-day-old male rat cultures and the differentiation of spermatogonia into round spermatids.The effect of a mixture of 1 μg/L of ATZ and 1 μg/L of BaP was then investigated either during or after the establishment of the BTB by using 8- or 20–22-day-old rats. Cultures were performed over a 3-week period. Our results show that claudin-11 and connexin 43 two proteins of the BTB, were impaired by the mixture which also reduced the number of round spermatids (the direct precursors of spermatozoa), by targeting the middle to late pachytene spermatocytes. These effects were observed in 8- and 20–22-day -old rat Seminiferous Tubule cultures. However, the decrease of the number of round spermatids was faster and more marked in the 8-day- than in the 20–22-day -old rat Seminiferous Tubule cultures. Our study emphasizes the possible influence of the age of an individual on the effect of (a) toxicant(s) on spermatogenesis.
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exposure to low dose bisphenol a impairs meiosis in the rat Seminiferous Tubule culture model a physiotoxicogenomic approach
PLOS ONE, 2014Co-Authors: Gerard Steinmetz, Guillaume Montillet, Mariehelene Perrard, Anderson Loundou, Philippe Durand, Marieroberte Guichaoua, Odette PratAbstract:Background: Bisphenol A (BPA) is one of the most widespread chemicals in the world and is suspected of being responsible for male reproductive impairments. Nevertheless, its molecular mode of action on spermatogenesis is unclear. This work combines physiology and toxicogenomics to identify mechanisms by which BPA affects the timing of meiosis and induces germ-cell abnormalities. Methods: We used a rat Seminiferous Tubule culture model mimicking the in vivo adult rat situation. BPA (1 nM and 10 nM) was added to the culture medium. Transcriptomic and meiotic studies were performed on the same cultures at the same exposure times (days 8, 14, and 21). Transcriptomics was performed using pangenomic rat microarrays. Immunocytochemistry was conducted with an anti-SCP3 antibody. Results: The gene expression analysis showed that the total number of differentially expressed transcripts was time but not dose dependent. We focused on 120 genes directly involved in the first meiotic prophase, sustaining immunocytochemistry. Sixty-two genes were directly involved in pairing and recombination, some of them with high fold changes. Immunocytochemistry indicated alteration of meiotic progression in the presence of BPA, with increased leptotene and decreased diplotene spermatocyte percentages and partial meiotic arrest at the pachytene checkpoint. Morphological abnormalities were observed at all stages of the meiotic prophase. The prevalent abnormalities were total asynapsis and apoptosis. Transcriptomic analysis sustained immunocytological observations. Conclusion: We showed that low doses of BPA alter numerous genes expression, especially those involved in the reproductive system, and severely impair crucial events of the meiotic prophase leading to partial arrest of meiosis in rat Seminiferous Tubule cultures.
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hexavalent chromium at low concentration alters sertoli cell barrier and connexin 43 gap junction but not claudin 11 and n cadherin in the rat Seminiferous Tubule culture model
Chemical Hazards in Industry, 2013Co-Authors: Mariehelene Perrard, Diane Carette, Georges Pointis, Nadia Prisant, Jerome Gilleron, Dominique Segretain, Philippe DurandAbstract:Exposure to toxic metals, specifically those belonging to the nonessential group leads to human health defects and among them reprotoxic effects. The mechanisms by which these metals produce their negative effects on spermatogenesis have not been fully elucidated. By using the Durand's validated Seminiferous Tubule culture model, which mimics the in vivo situation, we recently reported that concentrations of hexavalent chromium, reported in the literature to be closed to that found in the blood circulation of men, increase the number of germ cell cytogenetic abnormalities. Since this metal is also known to affect cellular junctions, the authors investigated, in the present study, its potential influence on the Sertoli cell barrier and on junctional proteins present at this level such as connexin 43, claudin-11 and N-cadherin. Cultured Seminiferous Tubules in bicameral chambers expressed the three junctional proteins and ZO-1 for at least 12 days. Exposure to low concentrations of chromium (10 µg/l) increased the trans-epithelial resistance without major changes of claudin-11 and N-cadherin expressions but strongly delocalized the gap junction protein connexin 43 from the membrane to the cytoplasm of Sertoli cells. The possibility that the hexavalent chromium-induced alteration of connexin 43 indirectly mediates the effect of the toxic metal on the blood-testis barrier dynamic is postulated.
Michael K Skinner - One of the best experts on this subject based on the ideXlab platform.
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transforming growth factor beta beta 1 beta 2 and beta 3 gene expression and action during pubertal development of the Seminiferous Tubule potential role at the onset of spermatogenesis
Molecular Endocrinology, 1993Co-Authors: Brian P Mullaney, Michael K SkinnerAbstract:The potential role of transforming growth factor-beta (TGF beta) as a mediator of cell-cell interactions during the pubertal development of the Seminiferous Tubule was examined. Mesenchymal-derived peritubular cells and epithelial-like Sertoli cells were isolated from prepubertal, midpubertal, and late pubertal rat testes. The developmental expression of the multiple forms of TGF beta (TGF beta 1, -beta 2, and -beta 3) in whole testis and isolated somatic cell types was determined using a nuclease protection analysis. TGF beta 1 and TGF beta 2 mRNA expression was predominant in the immature testis and decreased at the onset of puberty. TGF beta 3 mRNA expression, the most abundant form of TGF beta present, peaked at an early pubertal stage, coincident with the initiation of spermatogenesis. Peritubular and Sertoli cells expressed each isoform of TGF beta during development. Peritubular cell mRNA expression of TGF beta 1, -beta 2, and -beta 3 decreased during pubertal development upon differentiation of th...
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basic fibroblast growth factor bfgf gene expression and protein production during pubertal development of the Seminiferous Tubule follicle stimulating hormone induced sertoli cell bfgf expression
Endocrinology, 1992Co-Authors: Brian P Mullaney, Michael K SkinnerAbstract:The potential role of basic fibroblast growth factor (bFGF) as a mediator of cell-cell interactions in the growth and development of the testis was examined. Nuclease protection analysis was used to evaluate bFGF gene expression in the testis and other male reproductive tract tissues. bFGF expression was evident in seminal vesicle, prostate, epididymis, and, at low levels, testis of 20.day-old rats. The developmental expression of bFGF in whole testis and isolated somatic cells types was determined. Mesenchymal-derived peritubular cells and epithelial-like Sertoli cells were isolated from prepubertal, midpubertal, and late pubertal rat testes. In whole testis, bFGF expression is predominant early in prepubertal testicular development and decreases with sexual maturity. Both freshly isolated peritubular and Sertoli cells express bFGF at relatively constant levels during pubertal development, with a slight suppression at the late pubertal stages. Freshly isolated mature Leydig cells also expressed low levels of bFGF. Cultured Sertoli and peritubular cells produced bFGF-like proteins, including 1% and 24.kilodalton forms. Interestingly, FSH increased Sertoli cell bFGF gene expression and protein production. Previously, FSH and bFGF have been shown to stimulate immature Sertoli cell growth. The results of the current study suggest that the ability of FSH to regulate testis and Sertoli cell proliferation may in part be indirectly mediated through the local production and action of bFGF. bFGF has also previously been shown to localize in developing germinal cells. Therefore, FSH-induced Sertoli cell bFGF expression may mediate Sertoligerminal cell interactions involved in the control of the spermatogenic process. Observations demonstrate the presence of bFGF at a time coinciding with active growth of the somatic cell populations of the Seminiferous Tubule. Potential roles for bFGF in the Seminiferous Tubule to consider include angiogenesis of the Tubule, prepubertal Sertoli cell proliferation, and mediating Sertoli-germinal cell interactions. (Endocrinology 131: 2928-2934,1992)
