نتائج البحث - "Sperm chromatin"

81

The interaction of modified histones with the bromodomain testis-specific (BRDT) gene and its mRNA level in sperm of fertile donors and subfertile men

المؤلفون: C. Steilmann, Wolfgang Weidner, Jörn Pons-Kühnemann, Marek Bartkuhn, Klaus Steger, Márcia C O Cavalcanti, Agnieszka Paradowska, Hans-Christian Schuppe

المصدر: REPRODUCTION. 140:435-443

الوصف: As histone modifications have been suggested to be involved in the regulation of gene expression after fertilisation, the present study aimed to analyze the interaction between the bromodomain testis-specific (BRDT) gene and differentially modified histones in human spermatozoa. The BRDT transcript level was studied to identify possible correlations between epigenetic changes, mRNA level and subfertility associated with impaired sperm chromatin condensation. Chromatin immunoprecipitation (ChIP) was performed with ejaculates from fertile and subfertile men using antibodies against specifically acetylated and methylated histone H3. Immunoprecipitated DNA was analysed by real-time quantitative PCR with primer pairs for BRDT. The BRDT mRNA level was screened by real-time RT-PCR. ChIP assay revealed co-localisation of acetylated and methylated histones within promoter and exon regions of the BRDT gene in fertile men. Interestingly, reduced binding of investigated modified histone modifications was observed in the BRDT promoter of subfertile patients. Different mRNA levels of BRDT have been detected in a group of infertile patients, as well as in fertile men. Enrichment of methylated histones within the BRDT promoter of fertile sperm suggests that this epigenetic mark may cause repression of BRDT after fertilisation, and may be changed in infertile patients. Our data suggest that reduced histone methylation in the promoter of BRDT may be associated with increased transcript levels in subfertile patients.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::89b1e8c46c8f0d46a9fe653af7e041b5
https://doi.org/10.1530/rep-10-0139

82

Paternal Exposure to Cyclophosphamide Affects the Progression of Sperm Chromatin Decondensation and Activates a DNA Damage Response in the Prepronuclear Rat Zygote1

المؤلفون: Barbara F. Hales, Lisanne Grenier, Bernard Robaire

المصدر: Biology of Reproduction. 83:195-204

الوصف: Spermatozoon decondensation in the zygote leads to the initiation of chromatin remodeling during which protamines are removed and replaced with maternal histones. We hypothesize that damage to male germ cells induced by paternal exposure to cyclophosphamide may alter the timing of spermatozoal decondensation and the pattern of chromatin remodeling in the prepronuclear rat zygote. A specific order of sperm decondensation was observed, starting at the posterior end, proceeding to the ventral sides, followed by the tip, and finally the midbody region of the sperm head nucleus; subgroups of partially decondensed type a sperm nuclei were defined as types a1, a2, a3, and a4. Based on their frequencies relative to controls, paternal exposure to cyclophosphamide accelerated the timing of spermatozoal decondensation. Two distinct patterns of chromatin remodeling were observed for totally decondensed (type b) and recondensing (type c) sperm nuclei: H4K12ac showed a homogenous staining, whereas H3S10ph displayed a ring-like staining around the sperm nucleus; the distribution of these posttranslationally modified histones was not affected by cyclophosphamide exposure. In contrast, paternal cyclophosphamide treatment increased the number of gammaH2AX foci found in decondensing sperm nuclei. Small foci were significantly increased in type a2 and a3 nuclei, whereas a significant increase in the numbers of large foci was found in type b and c nuclei. This increase in gammaH2AX foci in the decondensing male genome suggests that damage recognition and repair pathways are initiated in prepronuclear rat zygotes. Thus, exposure of male rats to chronic low doses of cyclophosphamide accelerates spermatozoal decondensation and leads to the activation of gammaH2AX recognition of DNA damage in the male genome of the prepronuclear zygote.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::4b17e8c1ea255a186dc0ddb0efd2f1ab
https://doi.org/10.1095/biolreprod.109.083345

83

Human sperm chromatin stabilization: a proposed model including zinc bridges

المؤلفون: Lars Björndahl, Ulrik Kvist

المصدر: Molecular Human Reproduction. 16:23-29

الوصف: The primary focus of this review is to challenge the current concepts on sperm chromatin stability. The observations (i) that zinc depletion at ejaculation allows a rapid and total sperm chromatin decondensation without the addition of exogenous disulfide cleaving agents and (ii) that the human sperm chromatin contains one zinc for every protamine for every turn of the DNA helix suggest an alternative model for sperm chromatin structure may be plausible. An alternative model is therefore proposed, that the human spermatozoon could at ejaculation have a rapidly reversible zinc dependent chromatin stability: Zn(2+) stabilizes the structure and prevents the formation of excess disulfide bridges by a single mechanism, the formation of zinc bridges with protamine thiols of cysteine and potentially imidazole groups of histidine. Extraction of zinc enables two biologically totally different outcomes: immediate decondensation if chromatin fibers are concomitantly induced to repel (e.g. by phosphorylation in the ooplasm); otherwise freed thiols become committed into disulfide bridges creating a superstabilized chromatin. Spermatozoa in the zinc rich prostatic fluid (normally the first expelled ejaculate fraction) represent the physiological situation. Extraction of chromatin zinc can be accomplished by the seminal vesicular fluid. Collection of the ejaculate in one single container causes abnormal contact between spermatozoa and seminal vesicular fluid affecting the sperm chromatin stability. There are men in infertile couples with low content of sperm chromatin zinc due to loss of zinc during ejaculation and liquefaction. Tests for sperm DNA integrity may give false negative results due to decreased access for the assay to the DNA in superstabilized chromatin.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::46d8dc161786d69289ad31e38e912a61
https://doi.org/10.1093/molehr/gap099

84

Sperm head morphology is related to high deoxyribonucleic acid stainability assessed by sperm chromatin structure assay

المؤلفون: Abdulaziz Baazeem, Jason Boman, Simon Phillips, Annick Courchesne, Armand Zini, Isaac Jacques Kadoch, Maria San Gabriel, François Bissonnette

المصدر: Fertility and Sterility. 91:2495-2500

الوصف: Objective To examine the relationship between sperm strict morphology and sperm chromatin integrity. Design Prospective study. Setting Infertility clinic. Patient(s) Eighty-seven consecutive semen samples from non-azoospermic men presenting for infertility evaluation and 6 samples from fertile donors. Intervention(s) Assessment of standard semen parameters and sperm chromatin structure assay (SCSA) parameters (%DFI [DNA fragmentation index] and %HDS [high DNA stainability]). Evaluation of %HDS and %DFI after treatment with dithiothreitol (a thiol-reducing agent used to decondense sperm nuclei) was also undertaken. Main Outcome Measure(s) Relationship between sperm strict morphology defects and SCSA parameters (%DFI and %HDS). Result(s) We observed significant relationships between the percentage of normal sperm forms and both %HDS ( r = −0.40) and sperm motility ( r = 0.32). We also found significant relationships between sperm head defects and both %HDS ( r = 0.40) and sperm concentration ( r = −0.39). Sperm tail, midpiece, and neck defects were not significantly related to the SCSA parameters. Treatment of spermatozoa with dithiothreitol (to induce decondensation) resulted in a substantial increase in %HDS but no measurable change in %DFI. Conclusion(s) The observed relationship between sperm head defects and %HDS suggests that sperm head abnormalities may, in part, be due to incomplete sperm chromatin condensation.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::7e13f71caeb2055dfe5920f5099a6785
https://doi.org/10.1016/j.fertnstert.2008.03.032

Full Text via ClinicalKey

85

Correlation Between Defects in Chromatin Condensation of Human Spermatozoa Stained by Aniline Blue and Semen Characteristics

المؤلفون: M.L. Guihard‐Moscato, Marie-Jeanne Mayaux, J P Dadoune

المصدر: Andrologia. 20:211-217

مصطلحات موضوعية: education.field_of_study, medicine.diagnostic_test, Sperm chromatin condensation, Chemistry, Urology, Population, Semen, General Medicine, Semen analysis, Sperm, Staining, Chromatin, Andrology, Endocrinology, Prophase, medicine, education

الوصف: Human sperm heads which present disturbances of chromatin condensation are stained by acidic aniline, blue. To determine whether the proportion of unstained heads, i.e. with well condensed chromatin, can be considered as an index of sperm quality, a study was undertaken in 157 men during an infertility evaluation. In addition to the usual sperm characteristics, the percentages of unstained heads and of morphologically normal and abnormal forms were concomitantly evaluated. In a total of 15760 spermatozoa, the percentage of unstained heads was much higher in the population of morphologically normal forms than in that of abnormal forms (79.1% and 49.4% respectively, p less than 10(-9]. Among spermatozoa with structural abnormalities, it was much higher in cells with a single anomaly than in those with associated anomalies (53.9% and 40.6% respectively, p less than 10(-9]. When morphology was taken into account, only vitality was found to vary significantly with the percentage of unstained heads.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::59bb54925257a99be3fa1046ba14e58c
https://doi.org/10.1111/j.1439-0272.1988.tb01058.x

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86

Effects of scrotal insulation in Nellore bulls (Bos taurus indicus) on seminal quality and its relationship with in vitro fertilizing ability

المؤلفون: D. Pereira, Margot Alves Nunes Dode, A.E.D.F. Silva, Carlos Eurico dos Santos Fernandes

المساهمون: C. E. Fernandes, UFMS, Margot Alves Nunes Dode, Embrapa Recursos Genéticos e Biotecnologia, Daniela Costa Pereira bolsista Embrapa Recursos Genéticos e Biotecnologia, A. E. D. F. Silva, UNESP., Universidade Federal de Mato Grosso do Sul (UFMS), Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA), Universidade Estadual Paulista (UNESP)

المصدر: Repositório Institucional da EMBRAPA (Repository Open Access to Scientific Information from EMBRAPA-Alice)
Empresa Brasileira de Pesquisa Agropecuária (Embrapa)
instacron:EMBRAPA
Scopus
Repositório Institucional da UNESP
Universidade Estadual Paulista (UNESP)
instacron:UNESP

الوصف: Made available in DSpace on 2022-04-28T18:55:48Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-01-01 The objectives of this study were to assess the effects of induced testicular degeneration in Bos taurus indicus (Nellore) bulls on changes in seminal characteristics and fertilizing ability of sperm. Four Nellore bulls (30-36-month-old, 500-550 kg) with good seminal quality (>80% motile and morphologically normal sperm) had scrotal insulation applied for 5 d. Semen was collected by electroejaculation and cryopreserved at the pre-insulation moment, and 7, 14, and 21 d after insulation was removed. Gross motility, vigor of sperm movement (1-5), acrosome integrity, sperm morphology (phase-contrast microscopy), nuclear vacuoles and abnormal chromatin (Feulgen-stain) were determined after sperm preparations for in vitro fertilization (IVF). Prior to IVF, sperm were separated using a Percoll gradient (45% and 90%). Normal sperm decreased (P < 0.05) 14 and 21 d after insulation was removed. On 14 and 21 d, the incidence of head defects (9.7 ± 0.6 and 17.0 ± 0.8, respectively; mean ± S.E.M.) was higher (P < 0.05) in agreement with the incidence of nuclear vacuoles (14.0 ± 5.0 and 12.3 ± 2.3) and abnormal chromatin (24.4 ± 7.2 and 30.8 ± 2.8). Although the frequency of cleaved oocytes decreased only on 21 d (P < 0.05), blastocyst rates were lower (P < 0.05) than pre-insulation on 14 and 21 d. In regression analyses, only nuclear vacuoles, head defects and intact acrosome accounted for differences in cleavage (R2 = 0.38, 0.48, and 0.30, respectively) and blastocyst rates (R2 = 0.35, 0.37, and 0.44). Abnormal chromatin was associated only with blastocyst rates (R2 = 0.35). In conclusion, blastocyst rate was more sensitive than cleavage rate and the assessment of nuclear integrity is recommended to predict the fertilizing ability of bull sperm. © 2008 Elsevier Inc. All rights reserved. Departamento de Patologia Centro de Ciências Biológicas e da Saú Universidade Federal de Mato Grosso do Sul, 79070-900 Campo Grande, MS Embrapa Recursos Genéticos e Biotecnologia, W5 Norte, 70770-990 Brasilia, Distrito Federal Faculdade de Medicina Veterinária e Zootecnia UNESP, 18618-000 Campus de Botucatu, SP Faculdade de Medicina Veterinária e Zootecnia UNESP, 18618-000 Campus de Botucatu, SP

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5db76b4090a96167219dfa6f8d73db5b
https://doi.org/10.1016/j.theriogenology.2008.07.005

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87

Sperm protamine levels as indicators of fertilising potential in sexually mature male rats

المؤلفون: Jyoti Choudhari, Nafisa H. Balasinor, M. Aleem, Varsha Padwal, M. K. Gill-Sharma

المصدر: Andrologia. 40:29-37

الوصف: We have earlier reported that administration of cyproterone acetate, fluphenazine decanoate, tamoxifen citrate, oestradiol valerate to adult male rats, at doses of 50, 5.77, 0.71, 0.28 micromol kg(-1) body weight given for periods of 15, 60, 60, 10 days, respectively, partially suppressed/reduced availability of one or more reproductive hormones viz. LH, FSH, testosterone and reduced their siring ability. The reduction in epididymal sperm counts was not considerable after treatment with these drugs, but conventional methods of assessment of spermatozoa quality viz. sperm chromatin structure assay (SCSA), nuclear chromatin decondensation (NCD) assay, monobromobimane (mBBr) uptake, had shown quantifiable changes in caput sperm chromatin compaction and reduced the testicular levels of protamine 1. The present follow-up study attempts to quantify changes in caudal sperm chromatin which has undergone compaction in the epididymis, in the altered hormonal microenvironment of rats treated with cyproterone acetate, tamoxifen citrate, fluphenazine decanoate, oestradiol valerate, at doses of 50, 5.77, 0.71, 0.28 micromol kg(-1) body weight respectively given for periods of 15, 60, 60, 10 days, with a view to correlating these changes to reduction in their fertilising potential. During the androgen-dependent transit of spermatozoa from caput to cauda epididymis, thiol group oxidation and tyrosine phosphorylation of protamine occurs in maturing sperms concomitant with development of fertilising ability. The results indicate that conventional methods viz. SCSA, NCD, mBBr uptake fail to detect changes induced by hormone deficits in sperm chromatin condensation, as a result of maturation during transit from caput to cauda epididymis. Absence of protamine 1 in epididymal sperm was observed in either testosterone or FSH deficient rats that correlated with reduced fertilising potential. The study suggests that changes in LH/T or FSH affect a hitherto unknown common molecular mechanism in the testis, underlying the protamination of rat spermatozoa. In conclusion, loss of P1 occurs in adult male rats deprived of T or FSH and is a reliable detectable change in epididymal sperm indicative of chromatin condensation defects associated with endocrine imbalance and poor fertility status.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::0f4fa9feb71e39223f0798c168d41fc1
https://doi.org/10.1111/j.1439-0272.2008.00805.x

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88

Physiological role of phospholipid hydroperoxide glutathione peroxidase in mammals

المؤلفون: Manuela Schneider, Alexander Seiler, Georg W. Bornkamm, Marcus Conrad

المصدر: bchm. 388:1019-1025

الوصف: The redox enzyme phospholipid hydroperoxide glutathione peroxidase (PHGPx) has emerged as one of the most significant selenoenzymes in mammals, corroborated by early embryonic lethality of PHGPx null mice. PHGPx is one of five selenium-dependent glutathione peroxidases and the second glutathione peroxidase to be discovered in 1982. PHGPx has a particular position within this family owing to its peculiar structural and catalytic properties, its multifaceted roles during male gametogenesis, and its necessity for early mouse development. Interestingly, mice devoid of endogenous glutathione die at the same embryonic stage as PHGPx-deficient mice compatible with the hypothesis that a similar phenotype of embryonic lethality may be provoked by PHGPx deficiency and lack of its reducing substrate glutathione. Various gain- and loss-of-function approaches in mice have provided some insights into the physiological functions of PHGPx. These include a protective role for PHGPx in response to irradiation, increased resistance of transgenic PHGPx mice to toxin-induced liver damage, a putative role in various steps of embryogenesis, and a contribution to sperm chromatin condensation. The expression of three forms of PHGPx and early embryonic lethality call for more specific studies, such as tissue-specific disruption of PHGPx, to precisely understand the contribution of PHGPx to mammalian physiology and under pathological conditions.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::efbf69c849d3bca82f61efae5f927e67
https://doi.org/10.1515/bc.2007.130

89

A comparative evaluation of semen parameters in pre- and post-Hurricane Katrina human population

المؤلفون: Caner Baran, Wayne J.G. Hellstrom, Suresh C. Sikka

المصدر: Asian Journal of Andrology
Asian Journal of Andrology, Vol 17, Iss 4, Pp 676-680 (2015)

مصطلحات موضوعية: Male, seminal plasma biochemical markers, peroxiredoxins, sperm maturation, translation, ectoplasmic specialization, New Orleans area, lcsh:RC870-923, male infertility, cell stress, membrane packing, Postacrosomal Sheath WWI Domain Binding Protein, sperm parameters, antigen-presenting cells, Medicine, chemotaxis, oocyte activation, thiols, media_common, fertility, lipid rafts, reactive oxygen species, cell fate, nucleocytoplasmic transport, education.field_of_study, nanotechnology, Sperm Count, Cyclonic Storms, membrane fluidity, General Medicine, hyperthermia, peripheral tolerance, Sertoli cell, Spermatozoa, sperm behavior, macrophages, Sperm Motility, infertility, varicocele, normospermic infertile population, media_common.quotation_subject, high-density lipoprotein, Environment, thioredoxins, splicing, heat shock protein A2, proteomics, Semen, White blood cell, ubiquitin, importin, genomics, hypogonadism, Humans, cryobiology, education, Aged, Retrospective Studies, blood-testis barrier, flow cytometry, sperm-egg interactions, endangered species, Abstinence, lcsh:Diseases of the genitourinary system. Urology, Louisiana, Sperm, reverse cholesterol transport, ezrin, Semen Analysis, fertilization, karyopherin, egg, rheotaxis, gene regulation, thermotaxis, Demography, spermatid, paternal genome, sperm epigenetics, Musashi, sperm chromatin, male fertility, Leukocyte Count, Leydig cell, oxidative stress, autoimmunity, artificial insemination, apoptosis, conservation, Hurricane Katrina, Sperm Agglutination, molecular chaperone, Middle Aged, Fertility clinic, sperm DNA damage, medicine.anatomical_structure, spermatocyte, oxidases, biomarker, oxysterols, Original Article, RNA binding proteins, ultramorphology, membrane microdomains, epididymis, Adult, Urology, Population, Fertility, testis, sperm, sperm capacitation, Young Adult, dendritic cells, albumin, offspring, business.industry, ATP binding cassette transporters, sterol transporters, dehydrogenases, thioredoxin, retrospective semen analysis, spermatogenesis, Musashi-2, posttranscriptional control, Musashi-1, SPTRX3, business

الوصف: A natural disaster leading to accumulation of environmental contaminants may have substantial effects on the male reproductive system. Our aim was to compare and assess semen parameters in a normospermic population residing in the Southern Louisiana, USA area pre- and post-Hurricane Katrina. We retrospectively evaluated semen analyses data (n = 3452) of 1855 patients who attended the Tulane University Andrology/Fertility Clinic between 1999 and 2013. The study inclusion criteria were men whose semen analyses showed ≥ 1.5 ml volume; ≥15 million ml -1 sperm concentration; ≥39 million total sperm count; ≥40% motility; >30% morphology, with an abstinence interval of 2-7 days. After the inclusion criteria applied to the population, 367 normospermic patients were included in the study. Descriptive statistics and group-based analyses were performed to interpret the differences between the pre-Katrina (Group 1, 1999-2005) and the post-Katrina (Group 2, 2006-2013) populations. There were significant differences in motility, morphology, number of white blood cell, immature germ cell count, pH and presence of sperm agglutination, but surprisingly there were no significant differences in sperm count between the two populations. This long-term comparative analysis further documents that a major natural disaster with its accompanied environmental issues can influence certain semen parameters (e.g., motility and morphology) and, by extension, fertility potential of the population of such areas.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::95d450fb2322ba054a8c52bbc18e1c66
https://pubmed.ncbi.nlm.nih.gov/25677132

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90

A Comprehensive and Systematic Study of Semen Quality and Sperm Functional Status in Normozoospermic Controls and Infertile Males from South India

المؤلفون: G. Sreenivasa, S. Suttur Malini, Shivaprasad Hs, Kavitha P

المصدر: Andrology-Open Access.

مصطلحات موضوعية: endocrine system, medicine.diagnostic_test, urogenital system, media_common.quotation_subject, Semen, Fertility, General Medicine, Semen analysis, Biology, medicine.disease, Sperm, Male infertility, Andrology, Semen quality, Sperm chromatin decondensation, medicine, media_common, Sperm plasma membrane

الوصف: Objective: Despite, several global studies indicate the variations in semen characteristics that accounts for male infertility, the association of specific changes in semen quality and fertility status among different Indian communities are poorly investigated. With wide range of geographical locations, diverse lifestyle patterns, seasonal variations combined with heterogeneous population, India offers an excellent system to study genotype-to-phenotype correlation. Hence, the current study has been initiated in South Karnataka region of India, in order to examine the variations in semen quality and sperm functional status in infertile individuals compared with normozoospermic controls. Methods: WHO strict guidelines are followed for systematic semen analysis of 239 infertile and 244 normozoospermic control subjects. Results: Interestingly, compared to normozoospermic controls, higher percentage of physical abnormalities such as, low semen volume and reduced sperm count are observed in infertile men. Additionally, semen characteristics namely, vitality and motility values are significantly reduced in infertile than controls. Further, in sperm function test the lower scores are documented for hypo-osmotic swelling assay, but not for sperm chromatin decondensation and acrosome intactness examination, suggesting loss of sperm plasma membrane integrity in infertile men. Moreover, the observed changes in semen parameters and sperm function are also evident in different infertile sub-conditions with varied responses. Surprisingly, age wise analysis revealed reduction in sperm morphology scores, whereas, vitality, count, motility and volume remain unchanged with increasing age of infertile males. However, we recorded inverse relationship between age and sperm vitality as well as motility in normozoospermic control men. Together, though the scores for different semen parameters in normozoospermic control group are in accordance with WHO reference range, the infertile men displayed poor semen quality. Conclusion: Thus, our data establishes basic differences between infertile and normozoospermic control group in terms of semen characteristics and sperm functional status, but the cause may be attributable to genetic or environmental factors or interaction of the two, which necessitates further detailed examination in larger cohort among heterogeneous population.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::538030234c300cd4b0900b03df7200f9
https://doi.org/10.4172/2167-0250.1000137

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