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Wu N, Li Y, He X, Lin J, Long D, Cheng X, Brand-Saberi B, Wang G, Yang X. Retinoic Acid Signaling Plays a Crucial Role in Excessive Caffeine Intake-Disturbed Apoptosis and Differentiation of Myogenic Progenitors. Front Cell Dev Biol 2021; 9:586767. [PMID: 33791291 PMCID: PMC8006404 DOI: 10.3389/fcell.2021.586767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 02/04/2021] [Indexed: 11/13/2022] Open
Abstract
Whether or not the process of somitogenesis and myogenesis is affected by excessive caffeine intake still remains ambiguous. In this study, we first showed that caffeine treatment results in chest wall deformities and simultaneously reduced mRNA expressions of genes involved in myogenesis in the developing chicken embryos. We then used embryo cultures to assess in further detail how caffeine exposure affects the earliest steps of myogenesis, and we demonstrated that the caffeine treatment suppressed somitogenesis of chicken embryos by interfering with the expressions of crucial genes modulating apoptosis, proliferation, and differentiation of myogenic progenitors in differentiating somites. These phenotypes were abrogated by a retinoic acid (RA) antagonist in embryo cultures, even at low caffeine doses in C2C12 cells, implying that excess RA levels are responsible for these phenotypes in cells and possibly in vivo. These findings highlight that excessive caffeine exposure is negatively involved in regulating the development of myogenic progenitors through interfering with RA signaling. The RA somitogenesis/myogenesis pathway might be directly impacted by caffeine signaling rather than reflecting an indirect effect of the toxicity of excess caffeine dosage.
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Affiliation(s)
- Nian Wu
- Division of Histology and Embryology, International Joint Laboratory for Embryonic Development and Prenatal Medicine, Medical College, Jinan University, Guangzhou, China.,Key Laboratory for Regenerative Medicine of the Ministry of Education, Jinan University, Guangzhou, China
| | - Yingshi Li
- Division of Histology and Embryology, International Joint Laboratory for Embryonic Development and Prenatal Medicine, Medical College, Jinan University, Guangzhou, China
| | - Xiangyue He
- Division of Histology and Embryology, International Joint Laboratory for Embryonic Development and Prenatal Medicine, Medical College, Jinan University, Guangzhou, China.,Department of Pathology, Medical School, Jinan University, Guangzhou, China
| | - Jiayi Lin
- Division of Histology and Embryology, International Joint Laboratory for Embryonic Development and Prenatal Medicine, Medical College, Jinan University, Guangzhou, China
| | - Denglu Long
- Division of Histology and Embryology, International Joint Laboratory for Embryonic Development and Prenatal Medicine, Medical College, Jinan University, Guangzhou, China
| | - Xin Cheng
- Division of Histology and Embryology, International Joint Laboratory for Embryonic Development and Prenatal Medicine, Medical College, Jinan University, Guangzhou, China
| | - Beate Brand-Saberi
- Department of Anatomy and Molecular Embryology, Institute of Anatomy, Ruhr-University Bochum, Bochum, Germany
| | - Guang Wang
- Division of Histology and Embryology, International Joint Laboratory for Embryonic Development and Prenatal Medicine, Medical College, Jinan University, Guangzhou, China.,Key Laboratory for Regenerative Medicine of the Ministry of Education, Jinan University, Guangzhou, China
| | - Xuesong Yang
- Division of Histology and Embryology, International Joint Laboratory for Embryonic Development and Prenatal Medicine, Medical College, Jinan University, Guangzhou, China.,Key Laboratory for Regenerative Medicine of the Ministry of Education, Jinan University, Guangzhou, China
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Boa-Amponsem O, Zhang C, Burton D, Williams KP, Cole GJ. Ethanol and Cannabinoids Regulate Zebrafish GABAergic Neuron Development and Behavior in a Sonic Hedgehog and Fibroblast Growth Factor-Dependent Mechanism. Alcohol Clin Exp Res 2020; 44:1366-1377. [PMID: 32472575 DOI: 10.1111/acer.14383] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 05/19/2020] [Indexed: 01/03/2023]
Abstract
BACKGROUND Ethanol (EtOH) has diverse effects on nervous system development, which includes development and survival of GABAergic neurons in a sonic hedgehog (Shh) and fibroblast growth factor (Fgf)-dependent mechanism. Cannabinoids also function as inhibitors of Shh signaling, raising the possibility that EtOH and cannabinoids may interact to broadly disrupt neuronal function during brain development. METHODS Zebrafish embryos were exposed to a range of EtOH and/or cannabinoid receptor 1 (CB1R) agonist concentrations at specific developmental stages, in the absence or presence of morpholino oligonucleotides that disrupt shh expression. In situ hybridization was employed to analyze glutamic acid decarboxylase (gad1) gene expression as a marker of GABAergic neuron differentiation, and zebrafish behavior was analyzed using the novel tank diving test as a measure of risk-taking behavior. RESULTS Combined acute subthreshold EtOH and CB1R agonist exposure results in a marked reduction in gad1 mRNA expression in zebrafish forebrain. Consistent with the EtOH and cannabinoid effects on Shh signaling, fgf8 mRNA overexpression rescues the EtOH- and cannabinoid-induced decrease in gad1 gene expression and also prevents the changes in behavior induced by EtOH and cannabinoids. CONCLUSIONS These studies provide evidence that forebrain GABAergic neuron development and zebrafish risk-taking behavior are sensitive to both EtOH and cannabinoid exposure in a Shh- and Fgf-dependent mechanism, and provide additional evidence that a signaling pathway involving Shh and Fgf crosstalk is a critical target of EtOH and cannabinoids in FASD.
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Affiliation(s)
- Oswald Boa-Amponsem
- From the, Integrated Biosciences Program, (OB-A), North Carolina Central University, Durham, North Carolina.,Julius L. Chambers Biomedical/Biotechnology Research Institute, (OB-A, C-Z, GJC), North Carolina Central University, Durham, North Carolina
| | - Chengjin Zhang
- Julius L. Chambers Biomedical/Biotechnology Research Institute, (OB-A, C-Z, GJC), North Carolina Central University, Durham, North Carolina
| | - Derek Burton
- Biomanufacturing Research Institute and Technology Enterprise, (DB, KPW), North Carolina Central University, Durham, North Carolina
| | - Kevin P Williams
- Biomanufacturing Research Institute and Technology Enterprise, (DB, KPW), North Carolina Central University, Durham, North Carolina
| | - Gregory J Cole
- Julius L. Chambers Biomedical/Biotechnology Research Institute, (OB-A, C-Z, GJC), North Carolina Central University, Durham, North Carolina.,Department of Biological and Biomedical Sciences, (GJC), North Carolina Central University, Durham, North Carolina
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3
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McLachlan K, Vavasour I, MacKay A, Brain U, Oberlander T, Loock C, Reynolds JN, Beaulieu C. Myelin Water Fraction Imaging of the Brain in Children with Prenatal Alcohol Exposure. Alcohol Clin Exp Res 2019; 43:833-841. [PMID: 30889291 DOI: 10.1111/acer.14024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 03/10/2019] [Indexed: 01/20/2023]
Abstract
BACKGROUND Prenatal alcohol exposure (PAE) is linked to alterations of cerebral white matter, including volume and nonspecific diffusion magnetic resonance imaging (MRI) indices of microstructure in humans. Some animal models of PAE have demonstrated myelination deficiencies, but myelin levels have not yet been evaluated in individuals with PAE. Multiecho T2 MRI offers a quantitative method to estimate myelin water fraction (MWF; related to myelin content) noninvasively, which was used here to evaluate brain myelination in children with PAE. METHODS Participants with PAE (n = 10, 6 females, mean age 13.9 years, range 7 to 18 years) and controls (n = 14, 11 females, mean age 13.2 years, range 9 to 16 years) underwent 3T MRI of the brain. T2 images (15 minutes acquisition for 32 echoes) were used to create MWF maps from which mean MWF was measured in 12 regions of interest (ROIs) including 8 in white matter and 4 in deep gray matter. RESULTS As expected, across the combined sample, MWF was highest for major white matter tracts such as the internal capsule and genu/splenium of the corpus callosum (10 to 18%) while the caudate and putamen had MWF less than 5%. Mean MWF was similar across 11/12 brain white and gray matter regions for the PAE and control groups (L/R internal capsule, major forceps, putamen, caudate nucleus, L minor forceps, genu and splenium of corpus callosum). In the PAE group, MWF was positively correlated with age in the genu of corpus callosum and right minor forceps, notably 2 frontal tracts. CONCLUSIONS Given comparable MRI-derived myelination fraction measures in PAE relative to controls, white matter alterations shown in other imaging studies, such as diffusion tensor imaging, may reflect microstructural anomalies related to axon caliber and density.
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Affiliation(s)
| | - Irene Vavasour
- Department of Radiology , University of British Columbia, Vancouver, BC, Canada
| | - Alex MacKay
- Department of Radiology , University of British Columbia, Vancouver, BC, Canada.,Department of Physics and Astronomy , University of British Columbia, Vancouver, BC, Canada
| | - Ursula Brain
- Department of Pediatrics , University of British Columbia, Vancouver, BC, Canada
| | - Tim Oberlander
- Department of Pediatrics , University of British Columbia, Vancouver, BC, Canada
| | - Christine Loock
- Department of Pediatrics , University of British Columbia, Vancouver, BC, Canada
| | - James N Reynolds
- Department of Biomedical and Molecular Sciences , Queens University, Kingston, ON, Canada
| | - Christian Beaulieu
- Department of Biomedical Engineering , University of Alberta, Edmonton, AB, Canada
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Igit T, Colcimen N. Stereological examination of effects of ethanol on optic nerve in experimental alcohol model. Hum Exp Toxicol 2019; 38:610-615. [PMID: 30744420 DOI: 10.1177/0960327119828123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The objective of the present study was to perform histological and stereological examination of alcohol-induced changes in the optic nerve, considered an extension of white matter of the brain, in rats. This study included 20 male Wistar albino rats aged 60 days and weighing 190-220 g. The rats were divided into three groups: ethanol ( n = 7), maltodextrin ( n = 7), and control ( n = 6) groups. The ethanol group was administered ethanol at a dose of 6.4% (v/v) instead of water for 18 days; the maltodextrin group received maltodextrin for the same time period, and the control group was the sham group. At the end of the experiment, a 0.5-mm long section of the optic nerve starting from the optic chiasma was dissected and examined with routine microscopic histological examination methods. The modified Cavalieri method was used for stereological measurement. Total tissue area ratios were calculated with a point grid provided by the Shtereom 1.5 software package. The statistical comparison of the groups revealed that the ethanol group had a significant reduction in the number of axons and sheath area of the optic nerve compared to the control and maltodextrin groups ( p < 0.017, p < 0.022, respectively). These results indicate the toxic effects of ethanol on the optic nerve.
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Affiliation(s)
- T Igit
- Departments of Histology and Embryology, Van Yuzuncu Yil University, Van, Turkey
| | - N Colcimen
- Departments of Histology and Embryology, Van Yuzuncu Yil University, Van, Turkey
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Wang G, Chen BZ, Wang CJ, Zhang J, Gao LR, Chuai M, Bao Y, Yang X. Ethanol exposure leads to disorder of blood island formation in early chick embryo. Reprod Toxicol 2017; 73:96-104. [PMID: 28789864 DOI: 10.1016/j.reprotox.2017.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 07/10/2017] [Accepted: 08/03/2017] [Indexed: 10/19/2022]
Abstract
Ethanol's effect on embryonic vasculogenesis and its underlying mechanism is obscure. Using VE-cadherin in situ hybridization, we found blood islands formation was inhibited in area opaca, but abnormal VE-cadherin+ cells were seen in area pellucida. We hypothesise ethanol may affect blood island progenitor cell migration and differentiation. DiI and in vitro experiments revealed ethanol inhibited cell migration, Quantitative PCR analysis revealed that ethanol exposure enhanced cell differentiation in area pellucida of HH5 chick embryos and repressed cell differentiation in area pellucida of HH8 chick embryos. By exposing to 2,2'-azobis-amidinopropane dihydrochloride, a ROS inducer, which gave a similar anti-vasculogenesis effect as ethanol and this anti-vasculogenesis effect could be reversed by vitamin C. Overall, exposing early chick embryos to ethanol represses blood island progenitor cell migration but disturbed differentiation at a different stage, so that the disorder of blood island formation occurs through excess ROS production and altered vascular-associated gene expression.
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Affiliation(s)
- Guang Wang
- Division of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou 510632, China
| | - Bin-Zhen Chen
- Division of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou 510632, China
| | - Chao-Jie Wang
- Division of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou 510632, China
| | - Jing Zhang
- Division of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou 510632, China
| | - Lin-Rui Gao
- Division of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou 510632, China
| | - Manli Chuai
- Division of Cell and Developmental Biology, University of Dundee, Dundee, DD1 5EH, UK
| | - Yongping Bao
- Norwich Medical School, University of East Anglia, Norwich, Norfolk, UK
| | - Xuesong Yang
- Division of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou 510632, China.
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6
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Zhang C, Boa-Amponsem O, Cole GJ. Comparison of molecular marker expression in early zebrafish brain development following chronic ethanol or morpholino treatment. Exp Brain Res 2017; 235:2413-2423. [PMID: 28493069 DOI: 10.1007/s00221-017-4977-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 05/03/2017] [Indexed: 12/14/2022]
Abstract
This study was undertaken to ascertain whether defined markers of early zebrafish brain development are affected by chronic ethanol exposure or morpholino knockdown of agrin, sonic hedgehog, retinoic acid, and fibroblast growth factors, four signaling molecules that are suggested to be ethanol sensitive. Zebrafish embryos were exposed to 2% ethanol from 6 to 24 hpf or injected with agrin, shha, aldh1a3, or fgf8a morpholinos. In situ hybridization was employed to analyze otx2, pax6a, epha4a, krx20, pax2a, fgf8a, wnt1, and eng2b expression during early brain development. Our results showed that pax6a mRNA expression was decreased in eye, forebrain, and hindbrain of both chronic ethanol exposed and select MO treatments. Epha4a expression in rhombomere R1 boundary was decreased in chronic ethanol exposure and aldh1a3 morphants, lost in fgf8a morphants, but largely unaffected in agrin and shha morphants. Ectopic pax6a and epha4a expression in midbrain was only found in fgf8a morphants. These results suggest that while chronic ethanol induces obvious morphological change in brain architecture, many molecular markers of these brain structures are relatively unaffected by ethanol exposure.
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Affiliation(s)
- Chengjin Zhang
- Julius L. Chambers Biomedical/Biotechnology Research Institute, Durham, NC, USA
| | - Oswald Boa-Amponsem
- Julius L. Chambers Biomedical/Biotechnology Research Institute, Durham, NC, USA
- Integrated Biosciences Program, Durham, NC, USA
| | - Gregory J Cole
- Julius L. Chambers Biomedical/Biotechnology Research Institute, Durham, NC, USA.
- Department of Biological and Biomedical Sciences, North Carolina Central University, Durham, NC, 27707, USA.
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7
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Wang G, Zhong S, Zhang SY, Ma ZL, Chen JL, Lu WH, Cheng X, Chuai M, Lee KKH, Lu DX, Yang X. Angiogenesis is repressed by ethanol exposure during chick embryonic development. J Appl Toxicol 2015; 36:692-701. [PMID: 26177723 DOI: 10.1002/jat.3201] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 05/31/2015] [Accepted: 06/01/2015] [Indexed: 12/28/2022]
Abstract
It is now known that excess alcohol consumption during pregnancy can cause fetal alcohol syndrome to develop. However, it is not known whether excess ethanol exposure could directly affect angiogenesis in the embryo or angiogenesis being indirectly affected because of ethanol-induced fetal alcohol syndrome. Using the chick yolk sac membrane (YSM) model, we demonstrated that ethanol exposure dramatically inhibited angiogenesis in the YSM of 9-day-old chick embryos, in a dose-dependent manner. Likewise, the anti-angiogenesis effect of ethanol could be seen in the developing vessel plexus (at the same extra-embryonic regions) during earlier stages of embryo development. The anti-angiogenic effect of ethanol was found associated with excess reactive oxygen species (ROS) production; as glutathione peroxidase activity increased while superoxide dismutase 1 and 2 activities decreased in the YSMs. We further validated this observation by exposing chick embryos to 2,2'-azobis-amidinopropane dihydrochloride (a ROS inducer) and obtained a similar anti-angiogenesis effect as ethanol treatment. Semiquantitative reverse transcription-polymerase chain reaction analysis of the experimental YSMs revealed that expression of angiogenesis-related genes, vascular endothelial growth factor and its receptor, fibroblast growth factor 2 and hypoxia-inducible factor, were all repressed following ethanol and 2,2'-azobis-amidinopropane dihydrochloride treatment. In summary, our results suggest that excess ethanol exposure inhibits embryonic angiogenesis through promoting superfluous ROS production during embryo development.
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Affiliation(s)
- Guang Wang
- Division of Histology and Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou, People's Republic of China.,Department of Pathophysiology, Institute of Brain Research, Medical College, Jinan University, Guangzhou, People's Republic of China
| | - Shan Zhong
- Division of Histology and Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou, People's Republic of China
| | - Shi-yao Zhang
- Division of Histology and Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou, People's Republic of China
| | - Zheng-lai Ma
- Division of Histology and Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou, People's Republic of China
| | - Jian-long Chen
- Division of Histology and Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou, People's Republic of China
| | - Wen-hui Lu
- Division of Histology and Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou, People's Republic of China
| | - Xin Cheng
- Division of Histology and Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou, People's Republic of China
| | - Manli Chuai
- Division of Cell and Developmental Biology, University of Dundee, Dundee, UK
| | - Kenneth Ka Ho Lee
- Key Laboratory for Regenerative Medicine of the Ministry of Education, School of Biomedical Sciences, Chinese University of Hong Kong, Shatin, Hong Kong
| | - Da-xiang Lu
- Department of Pathophysiology, Institute of Brain Research, Medical College, Jinan University, Guangzhou, People's Republic of China
| | - Xuesong Yang
- Division of Histology and Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou, People's Republic of China
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8
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Cole GJ, Zhang C, Ojiaku P, Bell V, Devkota S, Mukhopadhyay S. Effects of ethanol exposure on nervous system development in zebrafish. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 299:255-315. [PMID: 22959306 DOI: 10.1016/b978-0-12-394310-1.00007-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Alcohol (ethanol) is a teratogen that adversely affects nervous system development in a wide range of animal species. In humans numerous congenital abnormalities arise as a result of fetal alcohol exposure, leading to a spectrum of disorders referred to as fetal alcohol spectrum disorder (FASD). These abnormalities include craniofacial defects as well as neurological defects that affect a variety of behaviors. These human FASD phenotypes are reproduced in the rodent central nervous system (CNS) following prenatal ethanol exposure. While the study of ethanol effects on zebrafish development has been more limited, several studies have shown that different strains of zebrafish exhibit differential susceptibility to ethanol-induced cyclopia, as well as behavioral deficits. Molecular mechanisms underlying the effects of ethanol on CNS development also appear to be shared between rodent and zebrafish. Thus, zebrafish appear to recapitulate the observed effects of ethanol on human and mouse CNS development, indicating that zebrafish can serve as a complimentary developmental model system to study the molecular basis of FASD. Recent studies examining the effect of ethanol exposure on zebrafish nervous system development are reviewed, with an emphasis on attempts to elucidate possible molecular pathways that may be impacted by developmental ethanol exposure. Recent work from our laboratories supports a role for perturbed extracellular matrix function in the pathology of ethanol exposure during zebrafish CNS development. The use of the zebrafish model to assess the effects of ethanol exposure on adult nervous system function as manifested by changes in zebrafish behavior is also discussed.
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Affiliation(s)
- Gregory J Cole
- Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, NC, USA
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9
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Zhang C, Ojiaku P, Cole GJ. Forebrain and hindbrain development in zebrafish is sensitive to ethanol exposure involving agrin, Fgf, and sonic hedgehog function. BIRTH DEFECTS RESEARCH. PART A, CLINICAL AND MOLECULAR TERATOLOGY 2013; 97:8-27. [PMID: 23184466 PMCID: PMC4230296 DOI: 10.1002/bdra.23099] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 10/05/2012] [Accepted: 10/11/2012] [Indexed: 01/14/2023]
Abstract
BACKGROUND Ethanol is a teratogen that affects numerous developmental processes in the nervous system, which includes development and survival of GABAergic and glutamatergic neurons. Possible molecular mechanisms accounting for ethanol's effects on nervous system development include perturbed fibroblast growth factor (Fgf) and Sonic hedgehog (Shh) signaling. In zebrafish, forebrain GABAergic neuron development is dependent on Fgf19 and Shh signaling. The present study was conducted to test the hypothesis that ethanol affects GABAergic and glutamatergic neuron development by disrupting Fgf, Shh, and agrin function. METHODS Zebrafish embryos were exposed to varying concentrations of ethanol during a range of developmental stages, in the absence or presence of morpholino oligonucleotides (MOs) that disrupt agrin or Shh function. In situ hybridization was used to analyze glutamic acid decarboxylase (GAD1) gene expression, as well as markers of glutamatergic neurons. RESULTS Acute ethanol exposure results in marked reduction in GAD1 gene expression in forebrain and hindbrain, and reduction of glutamatergic neuronal markers in hindbrain. Subthreshold ethanol exposure, combined with agrin or Shh MO treatment, produces a similar diminution in expression of markers for GABAergic and glutamatergic neurons. Consistent with the ethanol effects on Fgf and Shh pathways, Fgf19, Fgf8, or Shh mRNA overexpression rescues ethanol-induced decreases in GAD1 and Atonal1a gene expression. CONCLUSIONS These studies demonstrate that GABAergic and glutamatergic neuron development in zebrafish forebrain or cerebellum is sensitive to ethanol exposure, and provides additional evidence that a signaling pathway involving agrin, Fgfs and Shh may be a critical target of ethanol exposure during zebrafish embryogenesis.
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Affiliation(s)
- Chengjin Zhang
- Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, NC 27707
| | - Princess Ojiaku
- Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, NC 27707
- Department of Biology, North Carolina Central University, Durham, NC 27707
| | - Gregory J. Cole
- Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, NC 27707
- Department of Biology, North Carolina Central University, Durham, NC 27707
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10
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Kavoi BM, Makanya AN, Kiama SG. Anticancer drug vinblastine sulphate induces transient morphological changes on the olfactory mucosa of the rabbit. Anat Histol Embryol 2012; 41:374-87. [PMID: 22443492 DOI: 10.1111/j.1439-0264.2012.01147.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 02/21/2012] [Indexed: 10/28/2022]
Abstract
Vinblastine sulphate (VBS) is an anticancer drug that acts by disrupting microtubule dynamics of highly mitotic tissue cells. The consequences of VBS on the olfactory mucosa (OM), a tissue with high mitotic numbers, are not clearly understood. We used qualitative and quantitative methods to determine the structural changes that may be produced on the rabbit OM by VBS. Following a single dose (0.31 mg/kg) of this drug, the structure of the mucosa was greatly altered on the first 3-5 days. The alteration was characterized by disarrangement of the normal layering of nuclei of the epithelia, degeneration of axonal bundles, occurrence of blood vessels within the bundles, localized death of cells of Bowman's glands and glandular degeneration. Surprisingly on or after day 7 and progressively to day 15 post-exposure, the OM was observed to regenerate and acquire normal morphology, and the vessels disappeared from the bundles. Relative to control values, bundle diameters, olfactory cell densities and cilia numbers decreased to as low as 53.1, 75.2 and 71.4%, respectively, on day 5. Volume density for the bundles, which was 28.6% in controls, decreased to a lowest value of 16.8% on day 5. In contrast, the volume density for the blood vessels was significantly lower in controls (19.9%) than in treated animals at day 2 (25.8%), day 3 (34.3%) and day 5 (31.5%). These findings suggest that the changes induced on the rabbit OM by VBS are transient and that regenerative recovery leads to the restoration of the normal structure of the mucosa.
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Affiliation(s)
- B M Kavoi
- Department of Veterinary Anatomy & Physiology, University of Nairobi, Riverside Drive, PO Box 30197- 00100, Nairobi, Kenya.
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Dursun I, Jakubowska-Doğru E, van der List D, Liets LC, Coombs JL, Berman RF. Effects of early postnatal exposure to ethanol on retinal ganglion cell morphology and numbers of neurons in the dorsolateral geniculate in mice. Alcohol Clin Exp Res 2011; 35:2063-74. [PMID: 21651582 PMCID: PMC3410545 DOI: 10.1111/j.1530-0277.2011.01557.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND The adverse effects of fetal and early postnatal ethanol intoxication on peripheral organs and the central nervous system are well documented. Ocular defects have also been reported in about 90% of children with fetal alcohol syndrome, including microphthalmia, loss of neurons in the retinal ganglion cell (RGC) layer, optic nerve hypoplasia, and dysmyelination. However, little is known about perinatal ethanol effects on retinal cell morphology. Examination of the potential toxic effects of alcohol on the neuron architecture is important because the changes in dendritic geometry and synapse distribution directly affect the organization and functions of neural circuits. Thus, in the present study, estimations of the numbers of neurons in the ganglion cell layer and dorsolateral geniculate nucleus (dLGN), and a detailed analysis of RGC morphology were carried out in transgenic mice exposed to ethanol during the early postnatal period. METHODS The study was carried out in male and female transgenic mice expressing yellow fluorescent protein (YFP) controlled by a Thy-1 (thymus cell antigen 1) regulator on a C57 background. Ethanol (3 g/kg/d) was administered to mouse pups by intragastric intubation throughout postnatal days (PDs) 3 to 20. Intubation control (IC) and untreated control (C) groups were included. Blood alcohol concentration was measured in separate groups of pups on PDs 3, 10, and 20 at 4 different time points, 1, 1.5, 2, and 3 hours after the second intubation. Numbers of neurons in the ganglion cell layer and in the dLGN were quantified on PD20 using unbiased stereological procedures. RGC morphology was imaged by confocal microscopy and analyzed using Neurolucida software. RESULTS Binge-like ethanol exposure in mice during the early postnatal period from PDs 3 to 20 altered RGC morphology and resulted in a significant decrease in the numbers of neurons in the ganglion cell layer and in the dLGN. In the alcohol exposure group, out of 13 morphological parameters examined in RGCs, soma area was significantly reduced and dendritic tortuosity significantly increased. After neonatal exposure to ethanol, a decrease in total dendritic field area and an increase in the mean branch angle were also observed. Interestingly, RGC dendrite elongation and a decrease in the spine density were observed in the IC group, as compared to both ethanol-exposed and pure control subjects. There were no significant effects of alcohol exposure on total retinal area. CONCLUSIONS Early postnatal ethanol exposure affects development of the visual system, reducing the numbers of neurons in the ganglion cell layer and in the dLGN, and altering RGCs' morphology.
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Affiliation(s)
- Ilknur Dursun
- Department of Biological Sciences, Middle East Technical University, 06531 Ankara, Turkey
| | - Ewa Jakubowska-Doğru
- Department of Biological Sciences, Middle East Technical University, 06531 Ankara, Turkey
| | | | - Lauren C. Liets
- Department of Neurobiology, Physiology, and Behavior, UC Davis, Davis, CA 95616
| | - Julie L. Coombs
- Department of Neurobiology, Physiology, and Behavior, UC Davis, Davis, CA 95616
| | - Robert F. Berman
- Center for Neuroscience & Department of Neurological Surgery, UC Davis, Davis, CA 95616
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12
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Kennelly K, Brennan D, Chummun K, Giles S. Histological characterisation of the ethanol-induced microphthalmia phenotype in a chick embryo model system. Reprod Toxicol 2011; 32:227-34. [DOI: 10.1016/j.reprotox.2011.05.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 05/20/2011] [Accepted: 05/21/2011] [Indexed: 10/18/2022]
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13
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Zhang C, Turton QM, Mackinnon S, Sulik KK, Cole GJ. Agrin function associated with ocular development is a target of ethanol exposure in embryonic zebrafish. ACTA ACUST UNITED AC 2011; 91:129-41. [PMID: 21308976 DOI: 10.1002/bdra.20766] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 10/25/2010] [Accepted: 10/26/2010] [Indexed: 12/16/2022]
Abstract
BACKGROUND Alcohol (ethanol) is a teratogen known to affect the developing eyes, face, and brain. Among the ocular defects in fetal alcohol spectrum disorder (FASD) are microphthalmia and optic nerve hypoplasia. Employing zebrafish as an FASD model provides an excellent system to analyze the molecular basis of prenatal ethanol exposure-induced defects because embryos can be exposed to ethanol at defined developmental stages and affected genetic pathways can be examined. We have previously shown that disruption of agrin function in zebrafish embryos produces microphthalmia and optic nerve hypoplasia. METHODS Zebrafish embryos were exposed to varying concentrations of ethanol in the absence or presence of morpholino oligonucleotides (MOs) that disrupt agrin function. In situ hybridization was used to analyze ocular gene expression as a consequence of ethanol exposure and agrin knockdown. Morphologic analysis of zebrafish embryos was also conducted. RESULTS Acute ethanol exposure induces diminished agrin gene expression in zebrafish eyes and, importantly, combined treatment with subthreshold levels of agrin MO and ethanol produces pronounced microphthalmia, markedly reduces agrin gene expression, and perturbs Pax6a and Mbx gene expression. Microphthalmia produced by combined agrin MO and ethanol treatment was rescued by sonic hedgehog (Shh) mRNA overexpression, suggesting that ethanol-mediated disruption of agrin expression results in disrupted Shh function. CONCLUSIONS These studies illustrate the strong potential for using zebrafish as a model to aid in defining the molecular basis for ethanol's teratogenic effects. The results of this work suggest that agrin expression and function may be a target of ethanol exposure during embryogenesis.
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Affiliation(s)
- Chengjin Zhang
- Julius L. Chambers Biomedical/Biotechnology Research Institute, Department of Biology, North Carolina Central University, Durham, North Carolina 27707, USA
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14
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Traka M, Arasi K, Avila RL, Podojil JR, Christakos A, Miller SD, Soliven B, Popko B. A genetic mouse model of adult-onset, pervasive central nervous system demyelination with robust remyelination. ACTA ACUST UNITED AC 2010; 133:3017-29. [PMID: 20851998 DOI: 10.1093/brain/awq247] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Adult-onset demyelinating disorders of the central nervous system represent the most common neurological abnormalities in young adults. Nevertheless, our understanding of disease pathogenesis and recovery in demyelinating disorders remains incomplete. To facilitate investigation into these processes, we have developed a new mouse model system that allows for the induction of dipththeria toxin A subunit expression in adult oligodendrocytes, resulting in widespread oligodendrocyte loss and demyelination of the central nervous system. These mice develop severe ataxia and tremor that correlates with impaired axonal conduction in the spinal cord. Strikingly, these animals fully recover from their motor and physiological defects and display extensive oligodendrocyte replenishment and widespread remyelination. This model system demonstrates the robust reparative potential of myelin in the central nervous system and provides a promising model for the quantitative assessment of therapeutic interventions that promote remyelination.
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Affiliation(s)
- Maria Traka
- Department of Neurology, University of Chicago, 5841 South Maryland Avenue, Chicago, IL 60637, USA
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15
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Dlugos CA, Rabin RA. Ocular deficits associated with alcohol exposure during zebrafish development. J Comp Neurol 2007; 502:497-506. [PMID: 17394139 DOI: 10.1002/cne.21320] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Approximately 90% of fetal alcohol syndrome cases are accompanied by ocular abnormalities. The zebrafish (Danio rerio) is a well-known developmental model that provides an opportunity for better understanding the histological and cytological effects of developmental exposure to ethanol on the vertebrate eye. The purpose of the present study was to determine the gross, microscopic, and ultrastructual effects of developmental exposure to ethanol in the zebrafish model. Eggs were obtained from WT outbred zebrafish and exposed to 0%, 0.1%, 0.2%, 0.4%, 0.5%, or 1.0% (v/v) ethanol to assess viability and the effect of dose and duration of exposure on eye size. Light and electron microscopy were performed on ethanol-treated and control larvae. Results showed that ethanol treatment decreased viability by about 20% at concentrations of 0.1-0.5% ethanol and by 50% at 1.0% ethanol. Ethanol-related decreases in eye size were recorded at 6 days postfertilization (dpf) and were dose dependent. There were significant decreases in the volumes of the photoreceptor, inner nuclear, and ganglionic layers and in the lens of 9 dpf ethanol-exposed compared with control larvae. Ultrastructural examination showed signs of developmental lags in the ethanol-treated fish as well as abnormal retinal apoptosis in the 6 dpf ethanol-treated larvae compared with their controls. These results demonstrate that the developing zebrafish eye is sensitive to perturbation with ethanol and displays some of the eye deficits present in fetal alcohol syndrome.
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Affiliation(s)
- Cynthia A Dlugos
- Department of Pathology and Anatomical Sciences, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14214-3000, USA.
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Tufan AC, Abban G, Akdogan I, Erdogan D, Ozogul C. The effect of in ovo ethanol exposure on retina and optic nerve in a chick embryo model system. Reprod Toxicol 2006; 23:75-82. [PMID: 17074462 DOI: 10.1016/j.reprotox.2006.09.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2006] [Revised: 09/06/2006] [Accepted: 09/19/2006] [Indexed: 11/17/2022]
Abstract
Ocular anomalies seen in children with fetal alcohol syndrome (FAS) suggest that ocular structures are sensitive to alcohol exposure during their development. This study was designed to investigate the effect of in ovo ethanol (EtOH) exposure on retinal development and myelinization of optic nerve fibers at an ultra structural level in a chick embryo model system. Prior to incubation, fertilized chicken eggs were injected once with 100 microl of either 0.9% NaCl (vehicle control), or EtOH solutions at different doses (10, 30, or 50%, v:v in 0.9% NaCl) into their air sacs and incubated at 37.5 degrees C and saturation humidity. On day 20 embryos were analyzed in terms of their viability and growth and the optic cups including the optic nerves were dissected out. Specimens were processed for electron microscopy (EM). Results showed that, EtOH significantly decreased the viability of chick embryos (P < 0.045), and caused significant prenatal growth retardation (P < 0.004) in a dose-dependant manner. Light microscopy of semi thin sections revealed that prenatal exposure to EtOH resulted in both retinal degeneration and optic nerve hypoplasia (P < 0.001) in a dose-dependant manner. EM revealed that a dose-dependant decrease in the number of myelinated nerve fibers was profound in groups exposed to EtOH (P < 0.001). Furthermore, the myelin coats observed were thinner than those seen in control embryos. In groups exposed to EtOH myelin sheets were unorganized and contained vacuolar structures in between them. The tissue in between the cells and optic nerve fibers, on the other hand, lost its intact appearance with vacuolar and vesicular structures in between them. In addition, the optic nerve fibers contained granular accumulations in EtOH exposed groups. A dose dependent degeneration was also observed in retinas of EtOH exposed groups. The effect of EtOH was profound in pigment epithelium (PE), inner plexiform layer (IPL), and ganglion cell layer (GC). Mitochondrial deficiencies, and alterations in melanin granule number and distribution dominated the defects seen in PE. On the other hand, EM findings of all the affected layers were suggestive of induced cell death in EtOH exposed groups. Thus, this study suggests retinal development with the emphasis on melanin pigmentation in PE and optic nerve myelinization as potential targets of prenatal EtOH exposure and discusses potential mechanisms of EtOH action on these tissues.
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Affiliation(s)
- A Cevik Tufan
- Department of Histology and Embryology, Pamukkale University, School of Medicine, Denizli, Turkey.
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17
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David P, Subramaniam K. Prenatal alcohol exposure and early postnatal changes in the developing nerve-muscle system. ACTA ACUST UNITED AC 2006; 73:897-903. [PMID: 16228975 DOI: 10.1002/bdra.20190] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Extensive research on prenatal alcohol exposure has proven the potent teratogenicity of this substance of abuse. Children born to alcoholic mothers are often diagnosed with fetal alcohol syndrome (FAS). Those afflicted with FAS often have muscle weakness, muscle wasting, and atrophy. This study assessed the effects of prenatal alcohol exposure on the developing rat neuromuscular system. METHODS Pregnant Sprague-Dawley rats were injected intraperitoneally with 1.0 ml of 20% ethyl alcohol/100 gm body weight. Unexposed rats served as controls. The offspring were killed 2, 3, 4, and 5 weeks after birth, and their body weights were recorded. The tibialis anterior (TA) and extensor digitorum longus (EDL) muscles were recovered and weighed. The TA muscles were histochemically stained by silver cholinesterase in order to study the pattern of innervation. The EDL muscles were processed and stained by hematoxylin-eosin. The number and size of the EDL muscle fibers was quantified. The sciatic nerve was also removed and stained by Swank and Davenport's method to demonstrate the myelin pattern. RESULTS Assessment at the neuromuscular junction showed a higher proportion of endplates polyneuronally innervated in the alcohol-exposed rats. The muscle weights, as well as the number and size of the muscle fibers, were significantly reduced in these animals. A light-microscopy examination of the nerve sections revealed alterations in the connectivity of myelin. CONCLUSIONS The finding that a higher proportion of endplates were polyneuronally innervated in the alcohol-exposed rats indicates that the maturation process of the neuromuscular system was delayed, thus confirming the deleterious effects of alcohol on growth and maturation of the nerve-muscle system.
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MESH Headings
- Animals
- Animals, Newborn
- Central Nervous System Depressants/toxicity
- Child
- Child, Preschool
- Cholinesterases/metabolism
- Ethanol/administration & dosage
- Ethanol/toxicity
- Female
- Fetal Alcohol Spectrum Disorders/enzymology
- Fetal Alcohol Spectrum Disorders/pathology
- Humans
- Infant
- Infant, Newborn
- Injections, Intraperitoneal
- Motor Endplate/enzymology
- Motor Endplate/pathology
- Muscle Fibers, Skeletal/enzymology
- Muscle Fibers, Skeletal/pathology
- Muscle, Skeletal/enzymology
- Muscle, Skeletal/growth & development
- Muscle, Skeletal/pathology
- Myelin Sheath/enzymology
- Myelin Sheath/pathology
- Pregnancy
- Rats
- Rats, Sprague-Dawley
- Sciatic Nerve/enzymology
- Sciatic Nerve/growth & development
- Sciatic Nerve/pathology
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Affiliation(s)
- Pamela David
- Department of Anatomy, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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18
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Miki T, Harris SJ, Wilce PA, Takeuchi Y, Bedi KS. Effects of alcohol exposure during early life on neuron numbers in the rat hippocampus. I. Hilus neurons and granule cells. Hippocampus 2003; 13:388-98. [PMID: 12722979 DOI: 10.1002/hipo.10072] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We previously showed that 16-day-old rats exposed to a relatively high dose of ethanol at 10-15 postnatal days of age have fewer neurons in the hilus region of the hippocampus compared with controls. Dentate gyrus granule cell numbers, however, showed no statistically significant changes attributable to the ethanol treatment. It is possible that some of the changes in brain morphology, brought about as a result of the exposure to ethanol during early life, may not be manifested until later in life. This question has been further addressed in an extension to our previous study. Wistar rats were exposed to a relatively high daily dose of ethanol on postnatal days 10-15 by placement in a chamber containing ethanol vapour, for 3 h/day. The blood ethanol concentration was found to be approximately 430 mg/dl at the end of the period of exposure. Groups of ethanol-treated (ET), separation control (SC), and mother-reared control (MRC) rats were anaesthetised and killed either at 16 or 30 days of age by perfusion with phosphate-buffered 2.5% glutaraldehyde. The Cavalieri principle and the physical disector methods were used to estimate, respectively, the regional volumes and neuron cell numerical densities in the hilus and granule cell regions of the dentate gyrus. The total numbers of neurons in the hilus region and granule cell layer were computed from these estimates. It was found that 16-day-old animals had 398,000-441,000 granule cells, irrespective of group. The numbers of granule cells increased such that by 30 days of age, rats had 487,000-525,500 granule cells. However, there were no significant differences between ethanol-treated rats and their age-matched controls in granule cell numbers. In contrast, ethanol-treated rats had slightly but significantly fewer neurons in the hilus region than did control animals at 16 days of age, but not at 30 days of age. Therefore, it appears that a short period of ethanol exposure during early life can have effects on neuron numbers of some hippocampal neurons, but not others. The effects on hilar neuron numbers, observed as a result of such short periods of ethanol treatment, appeared to be transitory.
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Affiliation(s)
- Takanori Miki
- Department of Anatomy, Faculty of Medicine, Kagawa Medical University, Kagawa, Japan
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Abstract
PURPOSE To assess the anatomy of eyes presumed to be amblyopic and their fellow eyes. PARTICIPANTS Two hundred seventy-five patients diagnosed with amblyopia and 88 healthy or glaucomatous subjects. METHODS All subjects underwent complete examinations, including cycloplegic refraction, slit lamp examination, ophthalmoscopy, and retinal imaging. Axial lengths were determined on 263 amblyopic and 88 healthy and glaucomatous subjects by ultrasonic biometry. MAIN OUTCOME MEASURES Optic disc areas were determined by magnification correction of disc images performed with formulas. Dysversion of the optic disc was determined by simultaneous viewing of disc photographs, digitized images of both eyes, or both. RESULTS The mean disc area of eyes presumed to be amblyopic was 1.72 mm(2) +/- 0. 73 SD and 1.95 mm(2) +/- 0.69 SD for nonamblyopic eyes (P =.0017). The mean disc area for 176 optic discs of glaucomatous and healthy eyes was 2.61 mm(2) +/- 0.95 SD. The mean axial length for eyes in the general population is 23.65 mm +/- 1.35 SD. The healthy and glaucomatous group in this study had a mean axial length of 23.89 mm +/- 1.29 SD. The eyes with poorer vision that were assumed to be amblyopic averaged 22.42 mm +/- 2.01 SD in length, whereas their nonamblyopic fellow eyes averaged 22.83 mm +/- 1.89 SD (P =.022). The differences between eyes in the healthy population and eyes that are presumably amblyopic, as well as the healthy and fellow eyes, are highly significant (P <.0001)(7.0 x 10(-16)). CONCLUSION Vision impairment in presumed amblyopia is associated with optic nerve hypoplasia with relative microphthalmos, which is more notable in those eyes with poorer vision.
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Affiliation(s)
- P Lempert
- Department of Physiology, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA.
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HARRIS SIMONJ, WILCE PETER, BEDI KULDIPS. Exposure of rats to a high but not low dose of ethanol during early postnatal life increases the rate of loss of optic nerve axons and decreases the rate of myelination. J Anat 2000; 197 Pt 3:477-85. [PMID: 11117631 PMCID: PMC1468146 DOI: 10.1046/j.1469-7580.2000.19730477.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Visual system abnormalities are commonly encountered in the fetal alcohol syndrome although the level of exposure at which they become manifest is uncertain. In this study we have examined the effects of either low (ETLD) or high dose (ETHD) ethanol, given between postnatal days 4-9, on the axons of the rat optic nerve. Rats were exposed to ethanol vapour in a special chamber for a period of 3 h per day during the treatment period. The blood alcohol concentration in the ETLD animals averaged approximately 171 mg/dl and in the ETHD animals approximately 430 mg/dl at the end of the treatment on any given day. Groups of 10 and 30-d-old mother-reared control (MRC), separation control (SC), ETLD and ETHD rats were anaesthetised with an intraperitoneal injection of ketamine and xylazine, and killed by intracardiac perfusion with phosphate-buffered glutaraldehyde. In the 10-d-old rat optic nerves there was a total of approximately 145,000-165,000 axons in MRC, SC and ETLD animals. About 4% of these fibres were myelinated. The differences between these groups were not statistically significant. However, the 10-d-old ETHD animals had only about 75,000 optic nerve axons (P < 0.05) of which about 2.8 % were myelinated. By 30 d of age there was a total of between 75,000-90,000 optic nerve axons, irrespective of the group examined. The proportion of axons which were myelinated at this age was still significantly lower (P < 0.001) in the ETHD animals (approximately 77 %) than in the other groups (about 98 %). It is concluded that the normal stages of development and maturation of the rat optic nerve axons, as assessed in this study, can be severely compromised by exposure to a relatively high (but not low) dose of ethanol between postnatal d 4 and 9.
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Affiliation(s)
- SIMON J.
HARRIS
- Department of Anatomical Sciences, University of Queensland, St Lucia, Brisbane, Australia
| | - PETER WILCE
- Department of Biochemistry, University of Queensland, St Lucia, Brisbane, Australia
| | - KULDIP S.
BEDI
- Department of Anatomical Sciences, University of Queensland, St Lucia, Brisbane, Australia
- Correspondence to Dr Kuldip S. Bedi. Department of Anatomical Sciences, University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia. Tel: +61-7-3365-3058; fax: +61-7-3365-1299; e-mail:
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