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Aldeli N, Soukkarie C, Hanano A. Transcriptional, hormonal and histological alterations in the ovaries of BALB/c mice exposed to TCDD in connection with multigenerational female infertility. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 258:114990. [PMID: 37156038 DOI: 10.1016/j.ecoenv.2023.114990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 05/01/2023] [Accepted: 05/04/2023] [Indexed: 05/10/2023]
Abstract
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic congener of dioxins, has a proven reproductive toxicity. Due to the lack of evidence on the multigenerational female reproductive toxicity of TCDD through the maternal exposure, the current study aims to evaluate, on the one hand, the acute reproductive toxicity of TCDD on adult female pre-gestational exposed to a critical single dose of TCDD (25 μg/kg) for a week (group referred to as AFnG; adult female/non-gestation). On the other hand, the transcription, hormonal and histological effects of TCDD on the females of two generations F1 and F2, were also investigated after the exposure of pregnant females to TCDD on gestational day 13 (GD13) (group referred to as AFG; adult female/gestation). First, our data showed alternations in the ovarian expressional pattern of certain key genes involved in the detoxification of TCDD as well as in the biosynthesis of steroidal hormones. The expression of Cyp1a1 was highly induced in TCDD-AFnG group, but reduced in both F1 and F2. While the transcripts levels of Cyp11a1 and 3βhsd2 were decreased, Cyp19a1 transcripts were increased as a function of TCDD exposure. This was synchronized with a dramatic increase in the level of estradiol hormone in the females of both experimental groups. Beside a significant reduce in their size and weight, ovaries of TCDD-exposed females showed serious histological alterations marked by atrophy of the ovary, congestion in the blood vessels, necrosis in the layer of granular cells, dissolution of the oocyte and nucleus of ovarian follicles. Finally, the female fertility was dramatically affected across generations with a reduced male\female ratio. Our data indicate that the exposure of pregnant female to TCDD has serious negative effects in the female productive system across generations and suggest the use of hormonal alternation as biomarker to monitor and assess the indirect exposure of these generations to TCDD.
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Affiliation(s)
- Nour Aldeli
- Department of Animal Biology, Faculty of Sciences, University of Damascus, Damascus, Syria
| | - Chadi Soukkarie
- Department of Animal Biology, Faculty of Sciences, University of Damascus, Damascus, Syria
| | - Abdulsamie Hanano
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria (AECS), Damascus, Syria.
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2
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Vaamonde D, Hackney AC, Garcia Manso JM, Arriaza Ardiles E, Vaquero M. Birth sex ratio in the offspring of professional male soccer players: influence of exercise training load. Hum Reprod 2021; 35:2613-2618. [PMID: 33006607 DOI: 10.1093/humrep/deaa225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 07/26/2020] [Indexed: 11/14/2022] Open
Abstract
STUDY QUESTION Can the exercise training load of elite male athletes influence the sex ratio of their offspring? SUMMARY ANSWER This is the first study assessing the influence of exercise training load on the offspring sex ratio of children from male professional athletes, observing a bias toward more females being born as a result of both high-intensity and high-volume loads, with intensity having the greatest effect. WHAT IS KNOWN ALREADY There is a relatively constant population sex ratio of males to females among various species; however, certain events and circumstances may alter this population sex ratio favoring one sex over the other. STUDY DESIGN, SIZE, DURATION Observational, descriptive cross-sectional study with a duration of 3 months. PARTICIPANTS/MATERIALS, SETTING, METHODS Seventy-five male professional soccer players from First Division soccer teams. Offspring variables were sex of the offspring, number of children and order of birth. Exercise training variables were volume and intensity. MAIN RESULTS AND THE ROLE OF CHANCE Total offspring was 122 children (52 males (42.6%), 70 females (57.4%)). Analysis revealed that increase in either the volume (P < 0.001) or intensity (P < 0.001) of training by the players shifted the birth offspring ratio more toward females. Within the sample of females born, more births (i.e. number) were observed as a consequence of training at the highest intensity (45 out of 70; P < 0.001), no such pattern occurred within males (P > 0.05). When female versus male births were compared within each intensity, only the high-intensity comparison was significant (45 (75%) females vs 15 (25%) males, P < 0.001). LIMITATIONS, REASONS FOR CAUTION While this is the first study assessing differences in the sex ratio of the offspring of male athletes (i.e. soccer players), we acknowledge there are limitations and confounders within our approach; e.g. small sample size, ethnic background and variations in the timing of intercourse relative to ovulation as well as in sex hormone levels. As such, we propose that future research is needed to confirm or refute our findings. It is recommended that such work expand on the measurements obtained and conduct direct assessment of sperm characteristics. WIDER IMPLICATIONS OF THE FINDINGS The findings of the study support the fact that different stressors on the body may alter the sex of the offspring. While in the present study the stressor is the excessive training load of soccer players, other events may lead to similar results. The bias in offspring sex ratio may have important implications for demography and population dynamics, as well as genetic trait inheritance. STUDY FUNDING/COMPETING INTEREST(S) There is no funding nor competing interests. TRIAL REGISTRATION NUMBER N/A.
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Affiliation(s)
- D Vaamonde
- Department of Morphological Sciences, School of Medicine and Nursing, Universidad de Cordoba, Cordoba, Spain.,International Network on Physical Exercise and Fertility (INPEF), Córdoba, Spain
| | - A C Hackney
- International Network on Physical Exercise and Fertility (INPEF), Córdoba, Spain.,Department of Exercise & Sport Science, University of North Carolina, Chapel Hill, NC, USA
| | - J M Garcia Manso
- International Network on Physical Exercise and Fertility (INPEF), Córdoba, Spain.,Department of Physical Education, School of Physical Activity and Sports, Universidad de Las Palmas de Gran Canaria, Las Palmas, Canary Islands, Spain
| | - E Arriaza Ardiles
- Center of Advanced Studies, Universidad de Playa Ancha, Valparaiso, Chile
| | - M Vaquero
- Department of Public Health, School of Medicine and Nursing, Universidad de Córdoba, Córdoba, Spain.,IMIBIC Clinical and Epidemiological Research in Primary Care, Córdoba, Spain
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3
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Wan X, He X, Liu Q, Duan P, Li H. Frequent and mild scrotal heat stress impairs embryo development, implantation and offspring sex ratio in mice. Reprod Biomed Online 2020; 40:617-626. [DOI: 10.1016/j.rbmo.2020.01.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 01/24/2020] [Indexed: 01/11/2023]
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4
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Bircsak KM, Copes LT, King S, Prantner AM, Hwang WT, Gerton GL. The aryl hydrocarbon receptor mediates sex ratio distortion in the embryos sired by TCDD-exposed male mice. Reprod Toxicol 2020; 94:75-83. [PMID: 32335222 DOI: 10.1016/j.reprotox.2020.04.072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 03/25/2020] [Accepted: 04/15/2020] [Indexed: 10/24/2022]
Abstract
Many reports describe an association between preconceptional paternal exposure to environmental chemicals, including the persistent organic pollutant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) with an increased number of female offspring. We chronically treated wild-type C57BL/6 male mice with TCDD to investigate a role for the aryl hydrocarbon receptor (AHR) transcription factor. These mice had a 14 % lower male:female sex ratio than control mice, which was not observed in TCDD-treated Ahr knock out mice. AHR target genes Cyp1a1 and Ahrr were upregulated in the liver and testis of WT mice and Ahr expression was higher in the epididymis (2-fold) and liver (18-fold) than in whole testis tissue. The AHR protein was localized to round spermatids, elongating spermatids, and Leydig cells in the testis of WT mice. These studies demonstrate AHR involvement in the sex ratio distortion of TCDD-exposed males and the need for evaluating the molecular and genetic mechanism of this process.
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Affiliation(s)
- Kristin M Bircsak
- Department of Obstetrics and Gynecology, Center for Research on Reproduction and Women's Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Center of Excellence in Environmental Toxicology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Latresa T Copes
- Department of Obstetrics and Gynecology, Center for Research on Reproduction and Women's Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Sara King
- Department of Obstetrics and Gynecology, Center for Research on Reproduction and Women's Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Andrew M Prantner
- Department of Obstetrics and Gynecology, Center for Research on Reproduction and Women's Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Wei-Ting Hwang
- Center of Excellence in Environmental Toxicology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA; Department of Biostatistics, Epidemiology and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - George L Gerton
- Department of Obstetrics and Gynecology, Center for Research on Reproduction and Women's Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Center of Excellence in Environmental Toxicology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.
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5
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Viluksela M, Pohjanvirta R. Multigenerational and Transgenerational Effects of Dioxins. Int J Mol Sci 2019; 20:E2947. [PMID: 31212893 PMCID: PMC6627869 DOI: 10.3390/ijms20122947] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 06/12/2019] [Accepted: 06/13/2019] [Indexed: 12/12/2022] Open
Abstract
Dioxins are ubiquitous and persistent environmental contaminants whose background levels are still reason for concern. There is mounting evidence from both epidemiological and experimental studies that paternal exposure to the most potent congener of dioxins, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), can lower the male/female ratio of offspring. Moreover, in laboratory rodents and zebrafish, TCDD exposure of parent animals has been reported to result in reduced reproductive performance along with other adverse effects in subsequent generations, foremost through the paternal but also via the maternal germline. These impacts have been accompanied by epigenetic alterations in placenta and/or sperm cells, including changes in methylation patterns of imprinted genes. Here, we review recent key studies in this field with an attempt to provide an up-to-date picture of the present state of knowledge to the reader. These studies provide biological plausibility for the potential of dioxin exposure at a critical time-window to induce epigenetic alterations across multiple generations and the significance of aryl hydrocarbon receptor (AHR) in mediating these effects. Currently available data do not allow to accurately estimate the human health implications of these findings, although epidemiological evidence on lowered male/female ratio suggests that this effect may take place at realistic human exposure levels.
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Affiliation(s)
- Matti Viluksela
- School of Pharmacy and Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
- Environmental Health Unit, National Institute for Health and Welfare, P.O. Box 95, FI-70701 Kuopio, Finland.
| | - Raimo Pohjanvirta
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, P.O. Box 66, FI-00014 Helsinki, Finland.
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6
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Knutsen HK, Alexander J, Barregård L, Bignami M, Brüschweiler B, Ceccatelli S, Cottrill B, Dinovi M, Edler L, Grasl-Kraupp B, Hogstrand C, Nebbia CS, Oswald IP, Petersen A, Rose M, Roudot AC, Schwerdtle T, Vleminckx C, Vollmer G, Wallace H, Fürst P, Håkansson H, Halldorsson T, Lundebye AK, Pohjanvirta R, Rylander L, Smith A, van Loveren H, Waalkens-Berendsen I, Zeilmaker M, Binaglia M, Gómez Ruiz JÁ, Horváth Z, Christoph E, Ciccolallo L, Ramos Bordajandi L, Steinkellner H, Hoogenboom LR. Risk for animal and human health related to the presence of dioxins and dioxin-like PCBs in feed and food. EFSA J 2018; 16:e05333. [PMID: 32625737 PMCID: PMC7009407 DOI: 10.2903/j.efsa.2018.5333] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The European Commission asked EFSA for a scientific opinion on the risks for animal and human health related to the presence of dioxins (PCDD/Fs) and DL-PCBs in feed and food. The data from experimental animal and epidemiological studies were reviewed and it was decided to base the human risk assessment on effects observed in humans and to use animal data as supportive evidence. The critical effect was on semen quality, following pre- and postnatal exposure. The critical study showed a NOAEL of 7.0 pg WHO2005-TEQ/g fat in blood sampled at age 9 years based on PCDD/F-TEQs. No association was observed when including DL-PCB-TEQs. Using toxicokinetic modelling and taking into account the exposure from breastfeeding and a twofold higher intake during childhood, it was estimated that daily exposure in adolescents and adults should be below 0.25 pg TEQ/kg bw/day. The CONTAM Panel established a TWI of 2 pg TEQ/kg bw/week. With occurrence and consumption data from European countries, the mean and P95 intake of total TEQ by Adolescents, Adults, Elderly and Very Elderly varied between, respectively, 2.1 to 10.5, and 5.3 to 30.4 pg TEQ/kg bw/week, implying a considerable exceedance of the TWI. Toddlers and Other Children showed a higher exposure than older age groups, but this was accounted for when deriving the TWI. Exposure to PCDD/F-TEQ only was on average 2.4- and 2.7-fold lower for mean and P95 exposure than for total TEQ. PCDD/Fs and DL-PCBs are transferred to milk and eggs, and accumulate in fatty tissues and liver. Transfer rates and bioconcentration factors were identified for various species. The CONTAM Panel was not able to identify reference values in most farm and companion animals with the exception of NOAELs for mink, chicken and some fish species. The estimated exposure from feed for these species does not imply a risk.
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7
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Buser MC, Abadin HG, Irwin JL, Pohl HR. Windows of sensitivity to toxic chemicals in the development of reproductive effects: an analysis of ATSDR's toxicological profile database. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2018; 28:553-578. [PMID: 30022686 PMCID: PMC6261274 DOI: 10.1080/09603123.2018.1496235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 06/29/2018] [Indexed: 06/08/2023]
Abstract
Development of the fetus is a complex process influenced by many factors including genetics, maternal health, and environmental exposures to toxic chemicals. Adverse developmental effects on the reproductive system have the potential to harm generations beyond those directly exposed. Here, we review the available literature in Agency for Toxic Substances and Disease Registry toxicological profiles related to reproductive-developmental effects in animals following in utero exposure to chemicals. We attempt to identify windows of sensitivity. In the discussion, we correlate the findings with human development. The endpoints noted are fertility, estrus, anogenital distance, sex ratio, spermatogenesis, and mammary gland development. We identified some windows of sensitivity; however, the results were hampered by chronic-exposure studies designed to detect effects occurring throughout developmental, including multi-generational studies. This paper demonstrates the need for more acute studies in animals aimed at understanding time periods of development that are more susceptible to chemically induced adverse effects.
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Affiliation(s)
- Melanie C Buser
- a US Department of Health and Human Services , Agency for Toxic Substances and Disease Registry , Atlanta , GA , USA
| | - Henry G Abadin
- a US Department of Health and Human Services , Agency for Toxic Substances and Disease Registry , Atlanta , GA , USA
| | - John L Irwin
- a US Department of Health and Human Services , Agency for Toxic Substances and Disease Registry , Atlanta , GA , USA
| | - Hana R Pohl
- a US Department of Health and Human Services , Agency for Toxic Substances and Disease Registry , Atlanta , GA , USA
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8
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Effect of endocrine disruptors on the ratio of X and Y chromosome-bearing live spermatozoa. Reprod Toxicol 2018; 82:10-17. [PMID: 30219569 DOI: 10.1016/j.reprotox.2018.09.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/07/2018] [Accepted: 09/06/2018] [Indexed: 02/06/2023]
Abstract
Although equal numbers of X and Y spermatozoa are produced during spermatogenesis, the sex chromosome ratio in ejaculated spermatozoa can be altered by exposure to endocrine-disrupting chemicals (EDCs), which can be reflected by altered sex ratios at birth. Here, we hypothesized EDCs affect sperm functions and viability of X and Y chromosome-bearing human spermatozoa. After exposure to genistein (Gen), bisphenol A (BPA), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), dibromochloropropane (DBCP), and diazinon (Diaz), we evaluated motility, viability, capacitation, and differential viability of X and Y spermatozoa. All EDCs tested altered sperm viability, motility, and capacitation. Interestingly, the Y/X ratio of live spermatozoa was significantly lower in sperm treated with TCDD, DBCP, and Diaz than control spermatozoa. Our results suggest that some of EDCs have larger effects on the viability of Y spermatozoa than X spermatozoa, implicating that a reduction in Y sperm viability may result in a female-biased sex ratio of offspring at birth.
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9
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You YA, Mohamed EA, Rahman MS, Kwon WS, Song WH, Ryu BY, Pang MG. 2,3,7,8-Tetrachlorodibenzo-p-dioxin can alter the sex ratio of embryos with decreased viability of Y spermatozoa in mice. Reprod Toxicol 2018; 77:130-136. [PMID: 29505796 DOI: 10.1016/j.reprotox.2018.02.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 02/21/2018] [Accepted: 02/27/2018] [Indexed: 12/16/2022]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a reproductive and developmental toxicant that can alter the sex ratio of offspring (proportion of male offspring). We hypothesized that the alteration of sex ratio is associated with sex chromosome ratio of live spermatozoa affected by exposure to TCDD. After exposure to TCDD we analyzed simultaneously sperm sex chromosome constitution and viability, and evaluated sperm sex chromosome ratio association with embryo sex ratio in mice. Short-term exposure to TCDD affects the decreased sperm motility and viability, and the increased acrosome reaction. Interestingly, Y spermatozoa survived shorter than X spermatozoa at high concentrations of TCDD. Moreover, the decreased sex ratio of embryos was associated with the short lifespan of Y spermatozoa. Our results suggest that TCDD may affect the fertility of Y spermatozoa more than X spermatozoa. Further studies are needed to compare the difference of fertilizing capability between X and Y spermatozoa by the effect of TCDD.
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Affiliation(s)
- Young-Ah You
- Department of Animal Science & Technology, Chung-Ang University, Anseong, Gyeonggi-Do 456-756, Republic of Korea.
| | - Elsayed A Mohamed
- Department of Animal Science & Technology, Chung-Ang University, Anseong, Gyeonggi-Do 456-756, Republic of Korea.
| | - Md Saidur Rahman
- Department of Animal Science & Technology, Chung-Ang University, Anseong, Gyeonggi-Do 456-756, Republic of Korea.
| | - Woo-Sung Kwon
- Department of Animal Science & Technology, Chung-Ang University, Anseong, Gyeonggi-Do 456-756, Republic of Korea.
| | - Won-Hee Song
- Department of Animal Science & Technology, Chung-Ang University, Anseong, Gyeonggi-Do 456-756, Republic of Korea.
| | - Buom-Yong Ryu
- Department of Animal Science & Technology, Chung-Ang University, Anseong, Gyeonggi-Do 456-756, Republic of Korea.
| | - Myung-Geol Pang
- Department of Animal Science & Technology, Chung-Ang University, Anseong, Gyeonggi-Do 456-756, Republic of Korea.
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‘t Mannetje A, Eng A, Walls C, Dryson E, Kogevinas M, Brooks C, McLean D, Cheng S, Smith AH, Pearce N. Sex ratio of the offspring of New Zealand phenoxy herbicide producers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin. Occup Environ Med 2016; 74:24-29. [DOI: 10.1136/oemed-2016-103771] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 07/28/2016] [Accepted: 08/09/2016] [Indexed: 11/04/2022]
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11
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Edwards AM, Cameron EZ, Pereira JC, Ferguson‐Smith MA. Paternal sex allocation: how variable is the sperm sex ratio? J Zool (1987) 2016. [DOI: 10.1111/jzo.12317] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- A. M. Edwards
- School of Biological Sciences University of Tasmania Hobart TAS Australia
- Department of Veterinary Medicine University of Cambridge Cambridge UK
| | - E. Z. Cameron
- School of Biological Sciences University of Tasmania Hobart TAS Australia
| | - J. C. Pereira
- Department of Veterinary Medicine University of Cambridge Cambridge UK
- Cytocell Ltd. Cambridge Technopark Cambridge UK
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Kobayashi Y, Hirano T, Omotehara T, Hashimoto R, Umemura Y, Yuasa H, Masuda N, Kubota N, Minami K, Yanai S, Ishihara-Sugano M, Mantani Y, Yokoyama T, Kitagawa H, Hoshi N. Immunohistochemical analysis of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxicity on the developmental dentate gyrus and hippocampal fimbria in fetal mice. J Vet Med Sci 2015; 77:1355-61. [PMID: 26096965 PMCID: PMC4667650 DOI: 10.1292/jvms.15-0238] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Dioxins are widespread persistent environmental contaminants with adverse impacts on humans and experimental animals. Behavioral and cognitive functions are impaired by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure. TCDD exerts its toxicity via the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor. The hippocampus, which plays important roles in episodic memory and spatial function, is considered vulnerable to TCDD-induced neurotoxicity, because it contains the AhR. We herein investigated the effects of TCDD toxicity on hippocampal development in embryonic mice. TCDD was administered to dams at 8.5 days postcoitum with a single dose of 20, 200, 2,000 and 5,000 ng/kg body weight (groups T20, T200, T2000 and T5000, respectively), and the brains were dissected from their pups at embryonic day 18.5. Immunohistochemical analysis demonstrated that the Glial Fibrillary Acidic Protein (GFAP) immunoreactivities in the dentate gyrus (DG) were reduced in the T5000 group. Granular GFAP immunoreactivity was observed in the hippocampal fimbria, and the number of immunoreactive fimbria was significantly decreased in the T5000 group. The number of Proliferating Cell Nuclear Antigen (PCNA)-positive cells was decreased in all TCDD-exposed groups and significantly reduced in the T20, T200 and T5000 groups. Together, these results demonstrate that maternal TCDD exposure has adverse impacts on neural stem cells (NSCs), neural precursor cells (NPCs) and granular cells in the DG and disrupts the NSC maintenance and timing of differentiation in the hippocampal fimbria, which in turn interrupt neuronal development in future generations of mice.
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Affiliation(s)
- Yoshihiro Kobayashi
- Laboratory of Molecular Morphology, Department of Animal Science, Graduate School of Agricultural Science, Kobe University, Kobe, Hyogo 657-8501, Japan
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13
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Forgotten fathers: paternal influences on mammalian sex allocation. Trends Ecol Evol 2014; 29:158-64. [DOI: 10.1016/j.tree.2013.12.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 11/25/2013] [Accepted: 12/07/2013] [Indexed: 11/24/2022]
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14
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Somm E, Stouder C, Paoloni-Giacobino A. Effect of developmental dioxin exposure on methylation and expression of specific imprinted genes in mice. Reprod Toxicol 2013; 35:150-5. [DOI: 10.1016/j.reprotox.2012.10.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 10/12/2012] [Accepted: 10/30/2012] [Indexed: 11/24/2022]
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THE CATEGORIES OF EVIDENCE RELATING TO THE HYPOTHESIS THAT MAMMALIAN SEX RATIOS AT BIRTH ARE CAUSALLY RELATED TO THE HORMONE CONCENTRATIONS OF BOTH PARENTS AROUND THE TIME OF CONCEPTION. J Biosoc Sci 2010; 43:167-84. [DOI: 10.1017/s0021932010000660] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SummaryThis note categorizes the evidence for the hypothesis that mammalian offspring sex ratios (proportions male) are causally related to the hormone levels of both parents around the time of conception. Most of the evidence may be acknowledged to be correlational and observational. As such it might be suspected of having been selected; or of having been subject to other forms of bias or confounding; or, at any rate, of being inadequate as a firm basis for causal inference. However, there are other types of evidence that are not vulnerable to these types of criticism. These are from the following sources: (1) previously neglected data from Nazi Germany and Soviet Russia; (2) fulfilled predictions; (3) genetics; and (4) a network of logically (mathematically) related propositions, for some of which there is overwhelming empirical evidence. It is suggested that this variety of evidence confers greater overall credibility on the hypothesis than would be the case if all the evidence were of the same observational/correlational status. This observational/correlational evidence is tabulated to illustrate its consistency.
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Navara KJ. Programming of offspring sex ratios by maternal stress in humans: assessment of physiological mechanisms using a comparative approach. J Comp Physiol B 2010; 180:785-96. [PMID: 20544204 DOI: 10.1007/s00360-010-0483-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 05/18/2010] [Accepted: 05/20/2010] [Indexed: 01/23/2023]
Abstract
Sex ratio adjustment has become a hot topic in ecology and evolutionary biology, as documentations of sex ratio skews are numerous, and include examples in diverse animal species. Over the past several decades, scientists have repeatedly debated whether human sex ratios also significantly deviate toward one sex or the other based on environmental or social conditions. An increasing number of studies supports the idea that exposure to stressful conditions can influence the sexes of offspring produced by humans, a majority of which document significantly fewer males after exposure to adverse conditions such as severe life events, economic disruption, or natural disasters. From a comparative standpoint, these findings are similar to studies in non-human mammals and other vertebrate species showing a bias toward females during times of stress. However, the mechanisms by which stress-related biases in the offspring sex ratio may occur remain elusive, and the involvement of glucocorticoids indicating a true influence of stress itself remains unstudied. Here, I review the evidence that stressful events induce sex ratio adjustment in humans. Additionally, I discuss the possibility for glucocorticoid mediation of sex ratio adjustment and the potential reproductive stages during which stress-induced sex ratio adjustment may occur in humans and other mammals.
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Affiliation(s)
- Kristen J Navara
- Department of Poultry Science, The University of Georgia, 203 Poultry Science Building, 110 Cedar Street, Athens, GA 30605, USA.
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