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McPherson NO, Bakos HW, Owens JA, Setchell BP, Lane M. Improving metabolic health in obese male mice via diet and exercise restores embryo development and fetal growth. PLoS One 2013; 8:e71459. [PMID: 23977045 PMCID: PMC3747240 DOI: 10.1371/journal.pone.0071459] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 07/03/2013] [Indexed: 12/17/2022] Open
Abstract
Paternal obesity is now clearly associated with or causal of impaired embryo and fetal development and reduced pregnancy rates in humans and rodents. This appears to be a result of reduced blastocyst potential. Whether these adverse embryo and fetal outcomes can be ameliorated by interventions to reduce paternal obesity has not been established. Here, male mice fed a high fat diet (HFD) to induce obesity were used, to determine if early embryo and fetal development is improved by interventions of diet (CD) and/or exercise to reduce adiposity and improve metabolism. Exercise and to a lesser extent CD in obese males improved embryo development rates, with increased cell to cell contacts in the compacting embryo measured by E-cadherin in exercise interventions and subsequently, increased blastocyst trophectoderm (TE), inner cell mass (ICM) and epiblast cell numbers. Implantation rates and fetal development from resulting blastocysts were also improved by exercise in obese males. Additionally, all interventions to obese males increased fetal weight, with CD alone and exercise alone, also increasing fetal crown-rump length. Measures of embryo and fetal development correlated with paternal measures of glycaemia, insulin action and serum lipids regardless of paternal adiposity or intervention, suggesting a link between paternal metabolic health and subsequent embryo and fetal development. This is the first study to show that improvements to metabolic health of obese males through diet and exercise can improve embryo and fetal development, suggesting such interventions are likely to improve offspring health.
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Affiliation(s)
- Nicole O. McPherson
- School of Paediatrics and Reproductive Health, Discipline of Obstetrics and Gynaecology, University of Adelaide, South Australia, Australia
- * E-mail:
| | - Hassan W. Bakos
- School of Medicine, Discipline of Medicine, University of Adelaide, South Australia, Australia
- Repromed, Dulwich, South Australia, Australia
| | - Julie A. Owens
- School of Paediatrics and Reproductive Health, Discipline of Obstetrics and Gynaecology, University of Adelaide, South Australia, Australia
| | - Brian P. Setchell
- School of Medical Sciences, Discipline of Anatomy, University of Adelaide, South Australia, Australia
| | - Michelle Lane
- School of Paediatrics and Reproductive Health, Discipline of Obstetrics and Gynaecology, University of Adelaide, South Australia, Australia
- Repromed, Dulwich, South Australia, Australia
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Jeng HA, Pan CH, Chao MR. 1-Hydroxypyrene as a biomarker for assessing the effects of exposure to polycyclic aromatic hydrocarbons on semen quality and sperm DNA integrity. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2013; 48:152-158. [PMID: 23043336 DOI: 10.1080/03601234.2012.716741] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A cross-sectional study was conducted to assess whether urinary 1-hydroxypyrene (1-OHP) could serve as a biomarker to assess the effect of PAHs on cellular and molecular changes of sperm. Urine and semen samples were collected from a total of 65 healthy coke oven workers. Sperm quality parameters (concentration, motility, vitality, and morphology) and semen integrity (DNA fragmentation, 8-oxodGuo, bulky DNA adducts) were analyzed. Sixteen (16) targeted PAHs at the personal breathing zone area were monitored and quantified. Results showed that urinary 1-OHP positively correlated with measured levels of 16 targeted PAHs. Urinary 1-OHP did not significantly correlate with semen quality; however, PAHs with heavy molecular weight, e.g., benzo(g,h,i)perylene and benzo(k)fluoranthene, negatively correlated with morphology and motility of sperms (p = 0.02 and 0.002, p = 0.04 and 0.04, respectively). Urinary 1-OHP positively correlated with the level of 8-oxodGuo and bulky DNA adducts, but not DNA fragmentation. Urinary 1-OHP was a suitable biomarker for an estimate of biologically effective doses of PAH exposure. However, urinary 1-OHP may not be sufficient as a biomarker to assess both cellular and molecular changes of sperm induced by PAHs.
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Affiliation(s)
- Hueiwang Anna Jeng
- School of Community and Environmental Health, College of Health Sciences, Old Dominion University, Norfolk, Virginia, USA.
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Kabashima K, Yoshinaga D, Fang J, Matsuzaki M, Suzuki H. Cell cycle-dependent dynamics of cytoskeleton involving mitochondrial redistribution in hamster embryos. Reprod Domest Anim 2012; 48:267-71. [PMID: 22734634 DOI: 10.1111/j.1439-0531.2012.02143.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mitochondria-cytoskeleton interactions were studied in the hamster embryos during interphase and M phase of the cell cycle. Two-cell embryos were cultured for 1 h with nocodazole, cytochalasin D or in a combination of both inhibitors and then centrifuged at 10,000 × g for 2 min. The control embryos were only centrifuged with no inhibitor treatment. Centrifuged embryos were fluorescently stained to examine the distribution of active mitochondria and nuclear configuration. In the control 2-cell embryos, most mitochondria were accumulated at the perinuclear region with some at the cell cortex. Neither each inhibitor nor centrifugation did affect the distribution of mitochondria in interphase blastomeres. However, mitochondria were spun down towards the centrifugal pole in 71% (n = 41) of the interphase blastomeres treated with centrifugation following a combination of nocodazole plus cytochalasin D, suggesting that both microtubules and microfilaments may involve in mitochondrial redistribution during interphase of the cell cycle. In contrast, when M-phase blastomeres were treated with all drug treatments applied, including cytochalasin D, mitochondria had been usually dislocated in a unipolar cluster, suggesting that microfilaments, not microtubules, may involve in the mitochondrial redistribution during M phase of the cell cycle. The data indicate that microfilaments function in mitochondrial redistribution regardless of the stages of the cell cycle and that microtubules may strongly associate with mitochondria during the interphase but dissociate from them during the M phase.
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Affiliation(s)
- K Kabashima
- Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Japan
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Preconceptional paternal glycidamide exposure affects embryonic gene expression: Single embryo gene expression study following in vitro fertilization. Reprod Toxicol 2011; 32:463-71. [DOI: 10.1016/j.reprotox.2011.09.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 08/10/2011] [Accepted: 09/17/2011] [Indexed: 11/18/2022]
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Grenier L, Robaire B, Hales BF. Paternal cyclophosphamide exposure induces the formation of functional micronuclei during the first zygotic division. PLoS One 2011; 6:e27600. [PMID: 22110683 PMCID: PMC3217984 DOI: 10.1371/journal.pone.0027600] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2011] [Accepted: 10/20/2011] [Indexed: 11/22/2022] Open
Abstract
Paternal exposures to cancer chemotherapeutics or environmental chemicals may have adverse effects on progeny outcome that are manifested in the preimplantation embryo. The objectives of this study were to determine the impact of paternal exposure to cyclophosphamide, an anticancer alkylating agent, on the formation, chromatin origin and function of micronuclei in cleavage stage rat embryos. Male Sprague-Dawley rats were gavaged with saline or cyclophosphamide (6 mg/kg/day) for 4 weeks and mated to naturally cycling females to collect pronuclear zygotes and 2 to 8 cell embryos. Micronuclear chromatin structure was characterized using confocal microscopy to detect immunoreactivities for H3K9me3, a marker for maternal chromatin, and lamin B, a nuclear membrane marker. DNA synthesis was monitored using EdU (5-ethynyl-2′-deoxyuridine) incorporation. Fertilization by cyclophosphamide-exposed spermatozoa led to a dramatic elevation in micronuclei in cleavage stage embryos (control embryos: 1% to 5%; embryos sired by treated males: 70%). The formation of micronuclei occurred during the first zygotic division and was associated with a subsequent developmental delay. The absence of H3K9me3 indicated that these micronuclei were of paternal origin. The micronuclei had incomplete peri-nuclear and peri-nucleolar lamin B1 membrane formation but incorporated EdU into DNA to the same extent as the main nucleus. The formation of micronuclei in response to the presence of a damaged paternal genome may play a role in increasing the rate of embryo loss that is associated with the use of assisted reproductive technologies, parenthood among cancer survivors, and paternal aging.
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Affiliation(s)
- Lisanne Grenier
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Canada
| | - Bernard Robaire
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Canada
- Department of Obstetrics and Gynecology, McGill University, Montréal, Canada
- * E-mail:
| | - Barbara F. Hales
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Canada
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Johnson GD, Lalancette C, Linnemann AK, Leduc F, Boissonneault G, Krawetz SA. The sperm nucleus: chromatin, RNA, and the nuclear matrix. Reproduction 2011; 141:21-36. [PMID: 20876223 PMCID: PMC5358669 DOI: 10.1530/rep-10-0322] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Within the sperm nucleus, the paternal genome remains functionally inert and protected following protamination. This is marked by a structural morphogenesis that is heralded by a striking reduction in nuclear volume. Despite these changes, both human and mouse spermatozoa maintain low levels of nucleosomes that appear non-randomly distributed throughout the genome. These regions may be necessary for organizing higher order genomic structure through interactions with the nuclear matrix. The promoters of this transcriptionally quiescent genome are differentially marked by modified histones that may poise downstream epigenetic effects. This notion is supported by increasing evidence that the embryo inherits these differing levels of chromatin organization. In concert with the suite of RNAs retained in the mature sperm, they may synergistically interact to direct early embryonic gene expression. Irrespective, these features reflect the transcriptional history of spermatogenic differentiation. As such, they may soon be utilized as clinical markers of male fertility. In this review, we explore and discuss how this may be orchestrated.
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Affiliation(s)
- Graham D. Johnson
- The Center for Molecular Medicine and Genetics, Wayne State University of Medicine, C.S. Mott Center, 275 E. Hancock, Detroit, MI 48201
| | - Claudia Lalancette
- The Center for Molecular Medicine and Genetics, Wayne State University of Medicine, C.S. Mott Center, 275 E. Hancock, Detroit, MI 48201
- Department of Obstetrics and Gynecology, Wayne State University of Medicine, C.S. Mott Center, 275 E. Hancock, Detroit, MI 48201
| | - Amelia K. Linnemann
- The Center for Molecular Medicine and Genetics, Wayne State University of Medicine, C.S. Mott Center, 275 E. Hancock, Detroit, MI 48201
| | - Frédéric Leduc
- Department of Biochemistry, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, Québec, Canada J1H 5N4
| | - Guylain Boissonneault
- Department of Biochemistry, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, Québec, Canada J1H 5N4
| | - Stephen A. Krawetz
- The Center for Molecular Medicine and Genetics, Wayne State University of Medicine, C.S. Mott Center, 275 E. Hancock, Detroit, MI 48201
- Department of Obstetrics and Gynecology, Wayne State University of Medicine, C.S. Mott Center, 275 E. Hancock, Detroit, MI 48201
- Institute for Scientific Computing, Wayne State University of Medicine, C.S. Mott Center, 275 E. Hancock, Detroit, MI 48201
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Mátés L. Rodent transgenesis mediated by a novel hyperactive Sleeping Beauty transposon system. Methods Mol Biol 2011; 738:87-99. [PMID: 21431721 DOI: 10.1007/978-1-61779-099-7_6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
DNA-based transposons are natural gene delivery vehicles. Similarly to retroviruses, these elements -integrate into the chromosomes of host cells, but their life-cycle does not involve reverse transcription and they are not infectious. Transposon-based gene delivery has several advantageous features compared to viral methods; however, its efficacy has been the bottleneck of transposon utilization. Recently, using a novel strategy for in vitro evolution, we created a new hyperactive version (SB100X) of the vertebrate-specific Sleeping Beauty (SB) transposase. SB100X, when coupled with enhanced inverted terminal repeat structure T2 type SB transposons, is over 100-fold more active in mammalian cells than the prototype. We established protocol for SB100X mediated rodent transgenesis resulting on the average 35% transgenic founders with a low average number (1-2) of transgene insertions per founder. Due to these characteristics the SB100X based protocol opens the possibility of designing SB based transgenes also for in vivo knockdown experiments. By the same token, single copy transgene units introduced by the SB transposon system, more than being less prone to transgene silencing, also allow better control of transgene expression levels and patterns.
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Affiliation(s)
- Lajos Mátés
- Biological Research Center, Hungarian Academy of Sciences, Szeged, Hungary.
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8
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Ozolins̆ TR. Cyclophosphamide and the Teratology society: an awkward marriage. ACTA ACUST UNITED AC 2010; 89:289-99. [DOI: 10.1002/bdrb.20255] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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9
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Sperm DNA fragmentation: mechanisms of origin, impact on reproductive outcome, and analysis. Fertil Steril 2010; 93:1027-36. [PMID: 20080235 DOI: 10.1016/j.fertnstert.2009.10.046] [Citation(s) in RCA: 423] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Accepted: 10/27/2009] [Indexed: 12/22/2022]
Abstract
OBJECTIVE To review the mechanisms responsible for DNA fragmentation in human sperm, including those occurring during spermatogenesis and transport through the reproductive tract. The mechanisms examined include: apoptosis in the seminiferous tubule epithelium, defects in chromatin remodeling during the process of spermiogenesis, oxygen radical-induced DNA damage during sperm migration from the seminiferous tubules to the epididymis, the activation of sperm caspases and endonucleases, damage induced by chemotherapy and radiotherapy, and the effect of environmental toxicants. The different tests currently used for sperm DNA fragmentation analysis and the factors that determine the predictive value of sperm DNA fragmentation testing and their implications in the diagnosis and treatment of infertility are also discussed. Finally, we also scrutinize how the presence in the embryonic genome of DNA strand breaks or modifications of DNA nucleotides inherited from the paternal genome could impact the embryo and offspring. In particular we discuss how abnormal sperm could be dealt with by the oocyte and how sperm DNA abnormalities, which have not been satisfactorily repaired by the oocyte after fertilization, may interfere with normal embryo and fetal development. CONCLUSION(S) Sperm DNA can be modified through various mechanisms. The integrity of the paternal genome is therefore of paramount importance in the initiation and maintenance of a viable pregnancy both in a natural conception and in assisted reproduction. The need to diagnose sperm at a nuclear level is an area that needs further understanding so that we can improve treatment of the infertile couple.
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Previous maternal chemotherapy by cyclophosphamide (Cp) causes numerical chromosome abnormalities in preimplantation mouse embryos. Reprod Toxicol 2008; 26:278-81. [PMID: 18930809 DOI: 10.1016/j.reprotox.2008.09.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Revised: 09/08/2008] [Accepted: 09/30/2008] [Indexed: 11/20/2022]
Abstract
This study investigated the consequences of maternal cyclophosphamide treatment on fertilization rate, development and chromosomal integrity of embryos. It also evaluated efficiency of two methods of classic and metaphase induction for chromosomes assessment. Two different groups of NMRI mice 2-3 weeks and 6-7 weeks were injected intraperitonealy with 75 mg cyclophosphamide/kg. Six weeks later, oocytes were recovered, fertilized and incubated for 3 days in 5% CO(2) in air. Eight to 10 cell stage embryos were subjected to chromosomal study. Cyclophosphamide in both experimental groups reduced the oocyte fertilization rate and in the 6-7 weeks group it was significantly lower compared with control group (P<0.01). Also there was a reduction in 8-cell stage embryos formation from 48 to 72 h post-fertilization in both treated groups (P<0.05). Aneuploidy increased in the treatment groups compared with controls, which in the older group was significant (P<0.001). The success rate of the classic method to analyze metaphase plates was 30.1% and the success rate of heterokaryons formation with analyzable chromosomes was 67.8% in the metaphase induction method. In regards to the adverse effects of cyclophosphamide on fertilization rate, embryo development and chromosomal integrity of the mouse embryos, using Preimplantation Genetic Diagnosis in addition to Assisted Reproductive Technique is suggested.
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Codrington AM, Hales BF, Robaire B. Chronic cyclophosphamide exposure alters the profile of rat sperm nuclear matrix proteins. Biol Reprod 2007; 77:303-11. [PMID: 17475930 DOI: 10.1095/biolreprod.107.060244] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Chronic exposure of male rats to the alkylating agent cyclophosphamide, a well-known male-mediated developmental toxicant, alters gene expression in male germ cells as well as in early preimplantation embryos sired by cyclophosphamide-exposed males. Sperm DNA is organized by the nuclear matrix into loop-domains in a sequence-specific manner. In somatic cells, loop-domain organization is involved in gene regulation. Various structural and functional components of the nuclear matrix are targets for chemotherapeutic agents. Consequently, we hypothesized that cyclophosphamide treatment would alter the expression of sperm nuclear matrix proteins. Adult male rats were treated for 4 wk with saline or cyclophosphamide (6.0 mg kg(-1) day(-1)), and the nuclear matrix was extracted from cauda epididymal sperm. Proteins were analyzed by two-dimensional gel electrophoresis. Identified proteins within the nuclear matrix proteome were mainly involved in cell structure, transcription, translation, DNA binding, protein processing, signal transduction, metabolism, cell defense, or detoxification. Interestingly, cyclophosphamide selectively induced numerous changes in cell defense and detoxification proteins, most notably, in all known forms of the antioxidant enzyme glutathione peroxidase 4, in addition to an uncharacterized 54-kDa form; an overall increase in glutathione peroxidase 4 immunoreactivity was observed in the nuclear matrix extracts from cyclophosphamide-exposed spermatozoa. An increase in glutathione peroxidase 4 expression suggests a role for this enzyme in maintaining nuclear matrix stability and function. These results led us to propose that a change in composition of the nuclear matrix in response to drug exposure was a factor in altered sperm function and embryo development.
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Affiliation(s)
- Alexis M Codrington
- Department of Pharmacology, McGill University, Montreal, Quebec, Canada H3G 1Y6
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12
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Robaire B, Codrington AM, Hales BF. Molecular Changes in Sperm and Early Embryos after Paternal Exposure to a Chemotherapeutic Agent. MALE-MEDIATED DEVELOPMENTAL TOXICITY 2007. [DOI: 10.1039/9781847557643-00124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Bernard Robaire
- Department of Pharmacology and Therapeutics, McGill University Montreal Canada
- Department of Obstetrics and Gynecology, McGill University Montreal Canada
| | | | - Barbara F. Hales
- Department of Pharmacology and Therapeutics, McGill University Montreal Canada
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13
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de A Camargo LS, Powell AM, do Vale Filho VR, Wall RJ. Comparison of gene expression in individual preimplantation bovine embryos produced by in vitro fertilisation or somatic cell nuclear transfer. Reprod Fertil Dev 2006; 17:487-96. [PMID: 15907273 DOI: 10.1071/rd04128] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2004] [Accepted: 03/13/2005] [Indexed: 11/23/2022] Open
Abstract
In vitro fertilisation (IVF) and somatic cell nuclear transfer (SCNT) have been implicated in a variety of developmental abnormalities. Aberrant gene expression is likely to account for much of the diminished viability and developmental abnormalities observed. In the present study, the expression of multiple genes in IVF and SCNT bovine blastocyst-stage embryos were evaluated and compared with in vivo-produced embryos. Eleven genes expressed at and following maternal-zygotic transcription transition were evaluated in individual blastocysts by real-time polymerase chain reaction following RNA amplification. A subset of those genes was also evaluated in individual IVF and SCNT eight-cell embryos. A fibroblast-specific gene, expressed by nuclear donor cells, was also evaluated in IVF and SCNT embryos. The observed gene expression pattern at the eight-cell stage was not different between IVF and SCNT embryos (P > 0.05). In vitro fertilisation and SCNT blastocyst expression was lower (P < 0.01) for all genes compared with their in vivo-produced counterparts, except for lactate dehydrogenase isoenzyme A (P < 0.001). The patterns of gene expression of the IVF and SCNT blastocysts were indistinguishable. Neither SCNT eight-cell nor blastocyst-stage embryos expressed the gene used as a fibroblast marker (collagen VIalpha1). For the genes evaluated, the level of expression was influenced more by the environment than by the method used to produce the embryos. These results support the notion that if developmental differences observed in IVF- and SCNT-produced fetuses and neonates are the result of aberrant gene expression during the preimplantation stage, those differences in expression are subtle.
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Robaire B, Hales BF. Mechanisms of action of cyclophosphamide as a male-mediated developmental toxicant. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2004; 518:169-80. [PMID: 12817685 DOI: 10.1007/978-1-4419-9190-4_14] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Bernard Robaire
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC, H3G 1Y6, Canada.
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Hales BF, Robaire B. Paternal exposure to drugs and environmental chemicals: effects on progeny outcome. JOURNAL OF ANDROLOGY 2001; 22:927-36. [PMID: 11700855 DOI: 10.1002/j.1939-4640.2001.tb03431.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- B F Hales
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada.
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Harrouk W, Codrington A, Vinson R, Robaire B, Hales BF. Paternal exposure to cyclophosphamide induces DNA damage and alters the expression of DNA repair genes in the rat preimplantation embryo. Mutat Res 2000; 461:229-41. [PMID: 11056294 DOI: 10.1016/s0921-8777(00)00053-7] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Chronic low dose treatment of male rats with cyclophosphamide, an anticancer alkylating agent, damages male germ cells, resulting in greater than 80% peri-implantation progeny loss. Little transcription or repair takes place in the DNA of post-meiotic male germ cells. The spermatozoal genome regains its transcriptional capacity in the fertilized oocyte. We hypothesized that as a consequence of exposure of male rats to cyclophosphamide DNA damage to the male genome is transmitted to the conceptus; furthermore, this damage leads to alterations in the expression profiles of DNA repair genes during preimplantation development. Male rats were treated with either saline or cyclophosphamide (6mg/kg/day, 4-6 weeks) and mated to control females; 1-8 cell stage embryos were collected. The alkaline comet assay was used to assess DNA damage in 1-cell embryos. A significantly higher percentage (68%) of the embryos fertilized by cyclophosphamide-exposed spermatozoa displayed a comet indicative of DNA damage, compared to those sired by control males (18%). The in situ transcription/antisense RNA approach was used to determine if DNA damage alters the expression of DNA repair genes in early embryos. Dramatic increases in the transcripts for selected members of the nucleotide excision repair family (XPC, XPE and PCNA), mismatch repair family (PMS1), and recombination repair family (RAD50) were found in 1-cell stage embryos sired by cyclophosphamide-treated males compared to controls, while decreases in the expression of base excision repair family members (UNG1, UNG2, and XRCC1) and in recombination repair transcripts (RAD54) were observed. By the 8-cell stage, transcripts for specific members of the nucleotide excision repair family (XPC) and mismatch repair family (MSH2, PMS2) were elevated greatly in control embryos compared to embryos sired by drug-treated males; in contrast, transcripts for other members of the nucleotide excision repair family (XPE, PCNA), as well as some of the base excision repair family (UNG1), were elevated in embryos sired by drug-treated males. Therefore, DNA damage incurred in spermatozoa, following cyclophosphamide exposure is associated with alterations in the expression profiles of DNA repair genes in preimplantation embryos as early as the 1-cell stage. Genotoxic stress may disturb the nuclear remodeling and reprogramming events that follow fertilization and precede zygotic genome activation.
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Affiliation(s)
- W Harrouk
- Departments of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, H3G 1Y6, Quebec, Canada
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