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Netherton J, Ogle R, Hetherington L, Velkov T, Rose R, Baker M. DNA variants are an unlikely explanation for the changing quality of spermatozoa within the same individual. HUM FERTIL 2019; 24:376-388. [PMID: 31642381 DOI: 10.1080/14647273.2019.1679397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
It has recently been suggested that the human sperm genome is highly unstable, which may be a reasonable explanation as to why men, even fertile men, produce defective spermatozoa. Furthermore, an unstable genome may also explain why the semen profile of the same man changes from one ejaculate to the next. As such, we took multiple ejaculates (between 3 and 6) from 7 individuals over a 6-month period and isolated sperm through density gradients. We then compared the DNA of: (i) good and poor-quality spermatozoa within the same ejaculate; and (ii) from multiple ejaculates from the same individual. Our results suggest that on a global level, DNA present within spermatozoa is actually quite stable and similar between both good and poor sperm. This is important information for the assisted reproductive community when it comes to sperm selection.
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Affiliation(s)
- Jacob Netherton
- Department of Environmental and Life Sciences, University of Newcastle , Callaghan , New South Wales , Australia
| | - Rachel Ogle
- Department of Environmental and Life Sciences, University of Newcastle , Callaghan , New South Wales , Australia
| | - Louise Hetherington
- Department of Environmental and Life Sciences, University of Newcastle , Callaghan , New South Wales , Australia
| | - Tony Velkov
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne , Victoria , Australia
| | - Ryan Rose
- Fertility SA, St. Andrews Hospital , Adelaide , South Australia , Australia.,Adelaide Health and Medical Sciences, Robinson Research Institute, The University of Adelaide , Adelaide , South Australia , Australia
| | - Mark Baker
- Department of Environmental and Life Sciences, University of Newcastle , Callaghan , New South Wales , Australia
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Rajabi H, Mohseni-Kouchesfehani H, Salehi M, Farifteh-Nobijari F, Eslami-Arshaghi T. The influence of semen quality on male pronucleus demethylation process during ICSI cycle. Syst Biol Reprod Med 2017; 63:341-349. [PMID: 28841339 DOI: 10.1080/19396368.2017.1368735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
There is growing evidence that the spermatozoon's epigenetic structure is of the utmost importance in the health of the future embryo. Following fertilization, sperm chromatin undergoes epigenetic reprogramming including DNA demethylation and remethylation, which resets gene expression. In some infertile patients, it is inevitable that sperm cells that are not within the range of normal human sperm parameters will be used for intracytoplasmic sperm injection. Understanding the relationship between the human sperm parameters and male pronucleus DNA demethylation seems necessary. We hypothesized that demethylation of the male pronucleus might be altered in zygotes conceived from a spermatozoa obtained from a sample exhibiting an abnormal semen analysis profile. To test the hypothesis, sperm cells from normal and abnormal human semen samples were injected into mouse oocytes. A group of cultured zygotes was fixed before the onset of DNA demethylation and the other group was fixed after DNA demethylation. Both groups were then labeled with a 5 methylcytosine antibody and the level of pronuclei methylation was detected as a function of fluorescent intensity. The level of demethylation was then determined as the difference between 5 methylcytosine fluorescent intensity before and after DNA demethylation. A negative correlation (p<0.05) was observed between sperm motility, morphology, percentage of head defects, protamine deficiency, and DNA demethylation level. However, no correlation was found between the demethylation level and sperm count. In conclusion, these observations suggest that demethylation is altered in the male pronucleus when low quality sperm samples are used.
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Affiliation(s)
- Hoda Rajabi
- a Department of Animal Biology, Faculty of Biological Sciences , Kharazmi University , Tehran , Iran
| | | | - Mohammad Salehi
- b Infertility and Reproductive Health Research Center, Shahid Beheshti University of Medical Sciences , Tehran , Iran
| | - Fattaneh Farifteh-Nobijari
- c Cellular and Molecular Biology Research Center, Shahid Beheshti University of Medical Sciences , Tehran , Iran
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Hall SE, Nixon B, Aitken RJ. Non-surgical sterilisation methods may offer a sustainable solution to feral horse (Equus caballus) overpopulation. Reprod Fertil Dev 2017; 29:1655-1666. [DOI: 10.1071/rd16200] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 09/09/2016] [Indexed: 11/23/2022] Open
Abstract
Feral horses are a significant pest species in many parts of the world, contributing to land erosion, weed dispersal and the loss of native flora and fauna. There is an urgent need to modify feral horse management strategies to achieve public acceptance and long-term population control. One way to achieve this is by using non-surgical methods of sterilisation, which are suitable in the context of this mobile and long-lived species. In this review we consider the benefits of implementing novel mechanisms designed to elicit a state of permanent sterility (including redox cycling to generate oxidative stress in the gonad, random peptide phage display to target non-renewable germ cells and the generation of autoantibodies against proteins essential for conception via covalent modification) compared with that of traditional immunocontraceptive approaches. The need for a better understanding of mare folliculogenesis and conception factors, including maternal recognition of pregnancy, is also reviewed because they hold considerable potential in providing a non-surgical mechanism for sterilisation. In conclusion, the authors contend that non-surgical measures that are single shot and irreversible may provide a sustainable and effective strategy for feral horse control.
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Mitchell LA, De Iuliis GN, Aitken RJ. The TUNEL assay consistently underestimates DNA damage in human spermatozoa and is influenced by DNA compaction and cell vitality: development of an improved methodology. ACTA ACUST UNITED AC 2011; 34:2-13. [PMID: 20158539 DOI: 10.1111/j.1365-2605.2009.01042.x] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The purpose of this study was to evaluate the terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assay as a method for assessing DNA damage in human spermatozoa. The conventional assay was shown to be insensitive and unresponsive to the DNA fragmentation induced in human and mouse spermatozoa on exposure to Fenton reagents (H₂O₂ and Fe(2+) ). However, both time- and dose-dependent responses could be readily detected if the chromatin was exposed to 2 mm dithiothreitol (DTT) for 45 min prior to fixation. This modified version of the assay significantly enhanced the TUNEL signals generated by subpopulations of spermatozoa isolated on discontinuous Percoll gradients as well as the responses triggered by reagents (arachidonic acid and menadione) that are known to stimulate superoxide anion production by human spermatozoa. DTT exposure also improved the signals detected with chromomycin A₃ (CMA₃), a probe designed to determine the efficacy of chromatin protamination, and enhanced the correlation observed between this criterion of sperm quality and the TUNEL assay. Finally, the output of the TUNEL assay was found to be highly correlated with sperm vitality. The TUNEL methodology was therefore further refined to incorporate a vital stain that covalently bound to intracellular amine groups in non-viable cells. This tag remained associated with the spermatozoa during fixation and processing for the TUNEL assay so that ultimately, both DNA integrity and vitality could be simultaneously assessed in the same flow cytometry assay. The methods described in this article are simple and robust and should facilitate research into the causes of DNA damage in human spermatozoa.
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Affiliation(s)
- L A Mitchell
- The ARC Centre of Excellence in Biotechnology and Development, Reproductive Science Group, Discipline of Biological Sciences, School of Environmental and Life Sciences, University of Newcastle, Newcastle, NSW, Australia
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Aitken RJ, Koppers AJ. Apoptosis and DNA damage in human spermatozoa. Asian J Androl 2011; 13:36-42. [PMID: 20802502 PMCID: PMC3739394 DOI: 10.1038/aja.2010.68] [Citation(s) in RCA: 223] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Accepted: 06/25/2010] [Indexed: 01/13/2023] Open
Abstract
DNA damage is frequently encountered in spermatozoa of subfertile males and is correlated with a range of adverse clinical outcomes including impaired fertilization, disrupted preimplantation embryonic development, increased rates of miscarriage and an enhanced risk of disease in the progeny. The etiology of DNA fragmentation in human spermatozoa is closely correlated with the appearance of oxidative base adducts and evidence of impaired spermiogenesis. We hypothesize that oxidative stress impedes spermiogenesis, resulting in the generation of spermatozoa with poorly remodelled chromatin. These defective cells have a tendency to default to an apoptotic pathway associated with motility loss, caspase activation, phosphatidylserine exteriorization and the activation of free radical generation by the mitochondria. The latter induces lipid peroxidation and oxidative DNA damage, which then leads to DNA fragmentation and cell death. The physical architecture of spermatozoa prevents any nucleases activated as a result of this apoptotic process from gaining access to the nuclear DNA and inducing its fragmentation. It is for this reason that a majority of the DNA damage encountered in human spermatozoa seems to be oxidative. Given the important role that oxidative stress seems to have in the etiology of DNA damage, there should be an important role for antioxidants in the treatment of this condition. If oxidative DNA damage in spermatozoa is providing a sensitive readout of systemic oxidative stress, the implications of these findings could stretch beyond our immediate goal of trying to minimize DNA damage in spermatozoa as a prelude to assisted conception therapy.
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Affiliation(s)
- R John Aitken
- ARC Centre of Excellence in Biotechnology and Development, Priority Research Centre in Reproductive Science, Discipline of Biological Sciences, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia.
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Hypo-osmotic swelling test identifies individual spermatozoa with minimal DNA fragmentation. Reprod Biomed Online 2010; 21:474-84. [DOI: 10.1016/j.rbmo.2010.06.026] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 06/09/2010] [Accepted: 06/10/2010] [Indexed: 11/15/2022]
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Detrimental effects of antibiotics on mouse embryos in chromatin integrity, apoptosis and expression of zygotically activated genes. ZYGOTE 2010; 19:137-45. [PMID: 20587135 DOI: 10.1017/s0967199410000249] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The effects of specific components in culture medium on embryo physiology have been extensively investigated to optimize in vitro culture systems; however, little attention has been paid to antibiotics, the reagents used most commonly in culture systems to prevent contamination. To investigate the potential effects of routine use of antibiotics on cultured embryos, mouse zygotes were cultured with or without antibiotics. In both groups, the developmental rate and cell number of blastocysts appear to be normal. The proportion of embryos with blastomere fragmentation increased slightly when embryos were cultured with antibiotics. In contrast, the presence of antibiotics in the embryo culture system significantly disturbs expression of zygotically activated genes, damages chromatin integrity and increases apoptosis of cultured embryos. These results provide evidence that, when cultured with antibiotics, embryos with normal appearance may possess intrinsic physiological and genetic abnormalities. We demonstrate that the adverse effects of antibiotics on mammalian embryos are more severe than we previously presumed and that antibiotics are not essential for sterility of embryo culture system therefore abolishing antibiotic supplementation during embryo culture.
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Aitken RJ. Whither must spermatozoa wander? The future of laboratory seminology. Asian J Androl 2010; 12:99-103. [PMID: 20111089 DOI: 10.1038/aja.2008.42] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
This commentary celebrates the publication of the 5th edition of the World Health Organization Laboratory Manual for the Examination and Processing of Human Semen. This is the most complete text to date on the creation of a conventional semen profile and includes invaluable reference limits for specific aspects of semen quality based on the analysis of over 1 900 recent fathers. The new edition of the manual also includes detailed protocols for monitoring different aspects of sperm function and new chapters on the preparation of spermatozoa for assisted conception and cryopreservation. Given that this publication is the definitive statement on how to perform a descriptive semen analysis, we might speculate on the future of this field and the sorts of tests that might feature in future editions of the manual. Cell biologists are currently being empowered by the 'omics revolution, which is placing at their disposal technologies of unprecedented power to examine the biochemical composition of cells such as spermatozoa. Indeed, spermatozoa are perfect vehicles for this kind of analysis because they can be obtained as extremely pure suspensions, exist naturally in isolation and can be induced to express their capacity for fertilization and the initiation of embryonic development in vitro. The application of 'omics technologies to these cells, in concert with detailed assessments of their functional competence, should provide insights into the biochemical basis of defective semen quality. This information will then help us understand the causes of male infertility and to develop rational methods for its treatment and possible prevention.
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Affiliation(s)
- R John Aitken
- ARC Centre of Excellence in Biotechnology and Development, University of Newcastle, Callaghan NSW, Australia
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Mobile phone radiation induces reactive oxygen species production and DNA damage in human spermatozoa in vitro. PLoS One 2009; 4:e6446. [PMID: 19649291 PMCID: PMC2714176 DOI: 10.1371/journal.pone.0006446] [Citation(s) in RCA: 239] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2009] [Accepted: 06/30/2009] [Indexed: 11/19/2022] Open
Abstract
Background In recent times there has been some controversy over the impact of electromagnetic radiation on human health. The significance of mobile phone radiation on male reproduction is a key element of this debate since several studies have suggested a relationship between mobile phone use and semen quality. The potential mechanisms involved have not been established, however, human spermatozoa are known to be particularly vulnerable to oxidative stress by virtue of the abundant availability of substrates for free radical attack and the lack of cytoplasmic space to accommodate antioxidant enzymes. Moreover, the induction of oxidative stress in these cells not only perturbs their capacity for fertilization but also contributes to sperm DNA damage. The latter has, in turn, been linked with poor fertility, an increased incidence of miscarriage and morbidity in the offspring, including childhood cancer. In light of these associations, we have analyzed the influence of RF-EMR on the cell biology of human spermatozoa in vitro. Principal Findings Purified human spermatozoa were exposed to radio-frequency electromagnetic radiation (RF-EMR) tuned to 1.8 GHz and covering a range of specific absorption rates (SAR) from 0.4 W/kg to 27.5 W/kg. In step with increasing SAR, motility and vitality were significantly reduced after RF-EMR exposure, while the mitochondrial generation of reactive oxygen species and DNA fragmentation were significantly elevated (P<0.001). Furthermore, we also observed highly significant relationships between SAR, the oxidative DNA damage bio-marker, 8-OH-dG, and DNA fragmentation after RF-EMR exposure. Conclusions RF-EMR in both the power density and frequency range of mobile phones enhances mitochondrial reactive oxygen species generation by human spermatozoa, decreasing the motility and vitality of these cells while stimulating DNA base adduct formation and, ultimately DNA fragmentation. These findings have clear implications for the safety of extensive mobile phone use by males of reproductive age, potentially affecting both their fertility and the health and wellbeing of their offspring.
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Schatten H, Sun QY. The role of centrosomes in mammalian fertilization and its significance for ICSI. Mol Hum Reprod 2009; 15:531-8. [PMID: 19549764 DOI: 10.1093/molehr/gap049] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Centrosome integrity is critically important for successful fertilization and embryo development. In humans, the sperm contributes the dominant centrosomal material containing centrioles and centrosomal components onto which oocyte centrosomal proteins assemble after sperm incorporation to form the sperm aster that is essential for uniting sperm and oocyte pronuclei. Increasingly, dysfunctional sperm centrosomes have been identified as a factor for sperm-derived infertility and heterologous Intracytoplasmic Sperm Injection (ICSI) has been used to assess centrosome and sperm aster formation and clearly established a relationship between infertility and sperm centrosomal dysfunction. ICSI has been used successfully to provide novel treatment to overcome male factor infertility and it may open up new possibilities to correct specific sperm-related centrosome dysfunctions at molecular levels. New data indicate that it is now possible to replace dysfunctional centrosomes with functional donor sperm centrosomes which may provide new treatment for couples in which infertility is a result of centrosome-related sperm dysfunctions.
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Affiliation(s)
- Heide Schatten
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO, USA
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Aitken RJ, De Iuliis GN, McLachlan RI. Biological and clinical significance of DNA damage in the male germ line. ACTA ACUST UNITED AC 2009; 32:46-56. [DOI: 10.1111/j.1365-2605.2008.00943.x] [Citation(s) in RCA: 282] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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