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Gong Y, Ge L, Li Q, Gong J, Chen M, Gao H, Kang J, Yu T, Li J, Xu H. Ethanol Causes Cell Death and Neuronal Differentiation Defect During Initial Neurogenesis of the Neural Retina by Disrupting Calcium Signaling in Human Retinal Organoids. Stem Cell Rev Rep 2023; 19:2790-2806. [PMID: 37603136 DOI: 10.1007/s12015-023-10604-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/31/2023] [Indexed: 08/22/2023]
Abstract
Fetal Alcohol Syndrome (FAS) affects a significant proportion, exceeding 90%, of afflicted children, leading to severe ocular aberrations such as microphthalmia and optic nerve hypoplasia. During the early stages of pregnancy, the commencement of neural retina neurogenesis represents a critical period for human eye development, concurrently exposing the developing retinal structures to the highest risk of prenatal ethanol exposure due to a lack of awareness. Despite the paramount importance of this period, the precise influence and underlying mechanisms of short-term ethanol exposure on the developmental process of the human neural retina have remained largely elusive. In this study, we utilize the human embryonic stem cells derived retinal organoids (hROs) to recapitulate the initial retinal neurogenesis and find that 1% (v/v) ethanol slows the growth of hROs by inducing robust cell death and retinal ganglion cell differentiation defect. Bulk RNA-seq analysis and two-photon microscope live calcium imaging reveal altered calcium signaling dynamics derived from ethanol-induced down-regulation of RYR1 and CACNA1S. Moreover, the calcium-binding protein RET, one of the downstream effector genes of the calcium signaling pathway, synergistically integrates ethanol and calcium signals to abort neuron differentiation and cause cell death. To sum up, our study illustrates the effect and molecular mechanism of ethanol on the initial neurogenesis of the human embryonic neural retina, providing a novel interpretation of the ocular phenotype of FAS and potentially informing preventative measures for susceptible populations.
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Affiliation(s)
- Yu Gong
- Southwest Hospital/ Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, People's Republic of China
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, People's Republic of China
- Department of Ophthalmology, University-Town Hospital of Chongqing Medical University, Chongqing, China
| | - Lingling Ge
- Southwest Hospital/ Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, People's Republic of China
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, People's Republic of China
| | - Qiyou Li
- Southwest Hospital/ Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, People's Republic of China
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, People's Republic of China
| | - Jing Gong
- Southwest Hospital/ Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, People's Republic of China
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, People's Republic of China
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, 400044, China
| | - Min Chen
- Southwest Hospital/ Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, People's Republic of China
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, People's Republic of China
| | - Hui Gao
- Southwest Hospital/ Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, People's Republic of China
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, People's Republic of China
| | - Jiahui Kang
- Southwest Hospital/ Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, People's Republic of China
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, People's Republic of China
| | - Ting Yu
- Department of Clinical Laboratory, The 89th Hospital of The People's Liberation Army, Weifang, People's Republic of China
| | - Jiawen Li
- Department of Ophthalmology, University-Town Hospital of Chongqing Medical University, Chongqing, China.
| | - Haiwei Xu
- Southwest Hospital/ Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, People's Republic of China.
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, People's Republic of China.
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Darbinian N, Darbinyan A, Sinard J, Tatevosian G, Merabova N, D’Amico F, Khader T, Bajwa A, Martirosyan D, Gawlinski AK, Pursnani R, Zhao H, Amini S, Morrison M, Goetzl L, Selzer ME. Molecular Markers in Maternal Blood Exosomes Allow Early Detection of Fetal Alcohol Spectrum Disorders. Int J Mol Sci 2022; 24:ijms24010135. [PMID: 36613580 PMCID: PMC9820501 DOI: 10.3390/ijms24010135] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/15/2022] [Accepted: 12/17/2022] [Indexed: 12/24/2022] Open
Abstract
Prenatal alcohol exposure can cause developmental abnormalities (fetal alcohol spectrum disorders; FASD), including small eyes, face and brain, and neurobehavioral deficits. These cannot be detected early in pregnancy with available imaging techniques. Early diagnosis could facilitate development of therapeutic interventions. Banked human fetal brains and eyes at 9−22 weeks’ gestation were paired with maternal blood samples, analyzed for morphometry, protein, and RNA expression, and apoptotic signaling. Alcohol (EtOH)-exposed (maternal self-report) fetuses were compared with unexposed controls matched for fetal age, sex, and maternal race. Fetal brain-derived exosomes (FB-E) were isolated from maternal blood and analyzed for protein, RNA, and apoptotic markers. EtOH use by mothers, assessed by self-report, was associated with reduced fetal eye diameter, brain size, and markers of synaptogenesis. Brain caspase-3 activity was increased. The reduction in eye and brain sizes were highly correlated with amount of EtOH intake and caspase-3 activity. Levels of several biomarkers in FB-E, most strikingly myelin basic protein (MBP; r > 0.9), correlated highly with morphological abnormalities. Reduction in FB-E MBP levels was highly correlated with EtOH exposure (p < 1.0 × 10−10). Although the morphological features of FAS appear long before they can be detected by live imaging, FB-E in the mother’s blood may contain markers, particularly MBP, that predict FASD.
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Affiliation(s)
- Nune Darbinian
- Center for Neural Repair and Rehabilitation (Shriners Hospitals Pediatric Research Center), Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
- Correspondence: (N.D.); (M.E.S.); Tel.: +1-215-926-9318 (M.E.S.)
| | - Armine Darbinyan
- Department of Pathology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - John Sinard
- Department of Pathology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Gabriel Tatevosian
- Center for Neural Repair and Rehabilitation (Shriners Hospitals Pediatric Research Center), Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Nana Merabova
- Center for Neural Repair and Rehabilitation (Shriners Hospitals Pediatric Research Center), Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
- Medical College of Wisconsin-Prevea Health, Green Bay, WI 54304, USA
| | - Faith D’Amico
- Center for Neural Repair and Rehabilitation (Shriners Hospitals Pediatric Research Center), Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Tarek Khader
- Center for Neural Repair and Rehabilitation (Shriners Hospitals Pediatric Research Center), Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Ahsun Bajwa
- Center for Neural Repair and Rehabilitation (Shriners Hospitals Pediatric Research Center), Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Diana Martirosyan
- Center for Neural Repair and Rehabilitation (Shriners Hospitals Pediatric Research Center), Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Alina K. Gawlinski
- Center for Neural Repair and Rehabilitation (Shriners Hospitals Pediatric Research Center), Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Richa Pursnani
- Center for Neural Repair and Rehabilitation (Shriners Hospitals Pediatric Research Center), Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Huaqing Zhao
- Center for Biostatistics and Epidemiology, Department of Biomedical Education and Data Science, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Shohreh Amini
- Department of Biology, College of Science and Technology, Temple University, Philadelphia, PA 19122, USA
| | - Mary Morrison
- Department of Psychiatry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Laura Goetzl
- Department of Obstetrics & Gynecology, University of Texas, Houston, TX 77030, USA
| | - Michael E. Selzer
- Center for Neural Repair and Rehabilitation (Shriners Hospitals Pediatric Research Center), Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
- Department of Neurology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
- Correspondence: (N.D.); (M.E.S.); Tel.: +1-215-926-9318 (M.E.S.)
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Gyllencreutz E, Aring E, Landgren V, Landgren M, Gronlund MA. Thinner retinal nerve fibre layer in young adults with foetal alcohol spectrum disorders. Br J Ophthalmol 2020; 105:850-855. [PMID: 32620687 DOI: 10.1136/bjophthalmol-2020-316506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/26/2020] [Accepted: 06/09/2020] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIMS Ophthalmological abnormalities such as ptosis, strabismus, refractive errors and optic nerve hypoplasia have been reported in foetal alcohol spectrum disorders (FASD). The purpose of this study was to investigate whether retinal thickness, retinal nerve fibre layer (RNFL) and optic disc area (ODA) differ between individuals with FASD and healthy controls. METHODS Best-corrected visual acuity (BCVA) in terms of logarithm of the minimum angle of resolution (logMAR), refraction, and fundus variables measured by optical coherence tomography were obtained from 26 young adults with FASD (12 women, median age 23 years) and 27 controls (18 women, median age 25 years). RESULTS The total thickness of the peripapillary RNFL was significantly lower in the FASD group than in controls; median (range) in the right/left eye was 96.5 (60-109)/96 (59-107) µm in the FASD group and 105 (95-117)/103 (91-120) µm among controls (p=0.001 and p=0.0001). Macular RNFL and retinal thickness measurements from the FASD group were also lower in most of the nine ETDRS areas, except for the central parts. Median (range) BCVA in the best eye was 0.00 (-0.1-0.3) logMAR in the FASD group and 0.00 (-0.2-0.0) logMAR in controls (p=0.001). No significant differences between the groups were found regarding ODA or refraction. CONCLUSION Significant differences in peripapillary and macular RNFL, retinal thickness and BCVA were found in this group of young adults with FASD compared with healthy controls. However, there were no differences in the size of the optic disc.
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Affiliation(s)
- Emelie Gyllencreutz
- Clinical Neuroscience, University of Gothenburg Institute of Neuroscience and Physiology, Skövde, Sweden
| | - Eva Aring
- Clinical Neuroscience, University of Gothenburg Institute of Neuroscience and Physiology, Skövde, Sweden
| | - Valdemar Landgren
- Gillberg Neuropsychiatry Centre, University of Gothenburg Institute of Neuroscience and Physiology, Goteborg, Sweden
| | - Magnus Landgren
- Gillberg Neuropsychiatry Centre, University of Gothenburg Institute of Neuroscience and Physiology, Goteborg, Sweden
| | - Marita Andersson Gronlund
- Clinical Neuroscience, University of Gothenburg Institute of Neuroscience and Physiology, Skövde, Sweden
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Martin SA, Oshiro WM, Evansky PA, Degn LL, Ledbetter AD, Ford J, Todd Krantz Q, LeFew WR, Beasley TE, El-Masri H, McLanahan ED, Boyes WK, Bushnell PJ. Use of novel inhalation kinetic studies to refine physiologically-based pharmacokinetic models for ethanol in non-pregnant and pregnant rats. Inhal Toxicol 2015; 26:598-619. [PMID: 25144475 DOI: 10.3109/08958378.2014.938184] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Ethanol (EtOH) exposure induces a variety of concentration-dependent neurological and developmental effects in the rat. Physiologically-based pharmacokinetic (PBPK) models have been used to predict the inhalation exposure concentrations necessary to produce blood EtOH concentrations (BEC) in the range associated with these effects. Previous laboratory reports often lacked sufficient detail to adequately simulate reported exposure scenarios associated with BECs in this range, or lacked data on the time-course of EtOH in target tissues (e.g. brain, liver, eye, fetus). To address these data gaps, inhalation studies were performed at 5000, 10 000, and 21 000 ppm (6 h/d) in non-pregnant female Long-Evans (LE) rats and at 21 000 ppm (6.33 h/d) for 12 d of gestation in pregnant LE rats to evaluate our previously published PBPK models at toxicologically-relevant blood and tissue concentrations. Additionally, nose-only and whole-body plethysmography studies were conducted to refine model descriptions of respiration and uptake within the respiratory tract. The resulting time-course and plethysmography data from these in vivo studies were compared to simulations from our previously published models, after which the models were recalibrated to improve descriptions of tissue dosimetry by accounting for dose-dependencies in pharmacokinetic behavior. Simulations using the recalibrated models reproduced these data from non-pregnant, pregnant, and fetal rats to within a factor of 2 or better across datasets, resulting in a suite of model structures suitable for simulation of a broad range of EtOH exposure scenarios.
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Affiliation(s)
- Sheppard A Martin
- Neurotoxicology Branch/Toxicity Assessment Division, Office of Research and Development (ORD), US Environmental Protection Agency , Research Triangle Park, NC , USA
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Torres LH, Annoni R, Balestrin NT, Coleto PL, Duro SO, Garcia RCT, Pacheco-Neto M, Mauad T, Camarini R, Britto LRG, Marcourakis T. Environmental tobacco smoke in the early postnatal period induces impairment in brain myelination. Arch Toxicol 2014; 89:2051-8. [PMID: 25182420 DOI: 10.1007/s00204-014-1343-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 08/14/2014] [Indexed: 02/01/2023]
Abstract
Environmental tobacco smoke (ETS) is associated with high morbidity and mortality, mainly in children. However, few studies focus on the brain development effects of ETS exposure. Myelination mainly occurs in the early years of life in humans and the first three postnatal weeks in rodents and is sensitive to xenobiotics exposure. This study investigated the effects of early postnatal ETS exposure on myelination. BALB/c mice were exposed to ETS generated from 3R4F reference research cigarettes from the third to the fourteenth days of life. The myelination of nerve fibers in the optic nerve by morphometric analysis and the levels of Olig1 and myelin basic protein (MBP) were evaluated in the cerebellum, diencephalon, telencephalon, and brainstem in infancy, adolescence, and adulthood. Infant mice exposed to ETS showed a decrease in the percentage of myelinated fibers in the optic nerve, compared with controls. ETS induced a decrease in Olig1 protein levels in the cerebellum and brainstem and an increase in MBP levels in the cerebellum at infant. It was also found a decrease in MBP levels in the telencephalon and brainstem at adolescence and in the cerebellum and diencephalon at adulthood. The present study demonstrates that exposure to ETS, in a critical phase of development, affects the percentage of myelinated fibers and myelin-specific proteins in infant mice. Although we did not observe differences in the morphological analysis in adolescence and adulthood, there was a decrease in MBP levels in distinctive brain regions suggesting a delayed effect in adolescence and adulthood.
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Affiliation(s)
- Larissa H Torres
- Department of Clinical and Toxicological Analysis, Faculdade de Ciências Farmacêuticas, School of Pharmaceutical Sciences, University of São Paulo, Av Prof Lineu Prestes, 580 Bl 13B, São Paulo, SP, CEP 05508-000, Brazil
| | - Raquel Annoni
- Department of Pathology, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Natalia T Balestrin
- Department of Clinical and Toxicological Analysis, Faculdade de Ciências Farmacêuticas, School of Pharmaceutical Sciences, University of São Paulo, Av Prof Lineu Prestes, 580 Bl 13B, São Paulo, SP, CEP 05508-000, Brazil
| | - Priscila L Coleto
- Department of Clinical and Toxicological Analysis, Faculdade de Ciências Farmacêuticas, School of Pharmaceutical Sciences, University of São Paulo, Av Prof Lineu Prestes, 580 Bl 13B, São Paulo, SP, CEP 05508-000, Brazil
| | - Stephanie O Duro
- Department of Clinical and Toxicological Analysis, Faculdade de Ciências Farmacêuticas, School of Pharmaceutical Sciences, University of São Paulo, Av Prof Lineu Prestes, 580 Bl 13B, São Paulo, SP, CEP 05508-000, Brazil
| | - Raphael C T Garcia
- Department of Clinical and Toxicological Analysis, Faculdade de Ciências Farmacêuticas, School of Pharmaceutical Sciences, University of São Paulo, Av Prof Lineu Prestes, 580 Bl 13B, São Paulo, SP, CEP 05508-000, Brazil
| | - Maurílio Pacheco-Neto
- Department of Clinical Pathology, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Thais Mauad
- Department of Pathology, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Rosana Camarini
- Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Luiz R G Britto
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Tania Marcourakis
- Department of Clinical and Toxicological Analysis, Faculdade de Ciências Farmacêuticas, School of Pharmaceutical Sciences, University of São Paulo, Av Prof Lineu Prestes, 580 Bl 13B, São Paulo, SP, CEP 05508-000, Brazil.
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Lantz CL, Pulimood NS, Rodrigues-Junior WS, Chen CK, Manhaes AC, Kalatsky VA, Medina AE. Visual defects in a mouse model of fetal alcohol spectrum disorder. Front Pediatr 2014; 2:107. [PMID: 25346924 PMCID: PMC4191473 DOI: 10.3389/fped.2014.00107] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 09/17/2014] [Indexed: 11/23/2022] Open
Abstract
Alcohol consumption during pregnancy can lead to a multitude of neurological problems in offspring, varying from subtle behavioral changes to severe mental retardation. These alterations are collectively referred to as Fetal Alcohol Spectrum Disorders (FASD). Early alcohol exposure can strongly affect the visual system and children with FASD can exhibit an amblyopia-like pattern of visual acuity deficits even in the absence of optical and oculomotor disruption. Here, we test whether early alcohol exposure can lead to a disruption in visual acuity, using a model of FASD to mimic alcohol consumption in the last months of human gestation. To accomplish this, mice were exposed to ethanol (5 g/kg i.p.) or saline on postnatal days (P) 5, 7, and 9. Two to three weeks later we recorded visually evoked potentials to assess spatial frequency detection and contrast sensitivity, conducted electroretinography (ERG) to further assess visual function and imaged retinotopy using optical imaging of intrinsic signals. We observed that animals exposed to ethanol displayed spatial frequency acuity curves similar to controls. However, ethanol-treated animals showed a significant deficit in contrast sensitivity. Moreover, ERGs revealed a market decrease in both a- and b-waves amplitudes, and optical imaging suggest that both elevation and azimuth maps in ethanol-treated animals have a 10-20° greater map tilt compared to saline-treated controls. Overall, our findings suggest that binge alcohol drinking restricted to the last months of gestation in humans can lead to marked deficits in visual function.
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Affiliation(s)
- Crystal L Lantz
- Department of Anatomy, Virginia Commonwealth University , Richmond, VA , USA ; Department of Biology, University of Maryland , College Park, MD , USA
| | - Nisha S Pulimood
- Department of Pediatrics, University of Maryland School of Medicine , Baltimore, MD , USA
| | - Wandilson S Rodrigues-Junior
- Department of Pediatrics, University of Maryland School of Medicine , Baltimore, MD , USA ; Universidade Federal Fluminense , Niteroi , Brazil
| | | | - Alex C Manhaes
- Department of Pediatrics, University of Maryland School of Medicine , Baltimore, MD , USA ; Universidade do Estado do Rio de Janeiro , Rio de Janeiro , Brazil
| | | | - Alexandre Esteves Medina
- Department of Anatomy, Virginia Commonwealth University , Richmond, VA , USA ; Department of Pediatrics, University of Maryland School of Medicine , Baltimore, MD , USA
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Effects of early postnatal alcohol exposure on the developing retinogeniculate projections in C57BL/6 mice. Alcohol 2013; 47:173-9. [PMID: 23402901 DOI: 10.1016/j.alcohol.2012.12.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 12/21/2012] [Accepted: 12/24/2012] [Indexed: 12/13/2022]
Abstract
Previous studies on the adverse effects of perinatal exposure to ethanol (EtOH) on the developing visual system mainly focused on retinal and optic nerve morphology. The aim of the present study was to investigate whether earlier reported retinal and optic nerve changes are accompanied by anomalies in eye-specific fiber segregation in the dorsal lateral geniculate nucleus (dLGN). C57BL/6 mice pups were exposed to ethanol by intragastric intubation at either 3 or 4 g/kg from postnatal days (PD) 3-10, the third trimester equivalent to human gestation. Control (C) and intubation control (IC) groups not exposed to ethanol were included. On PD9, retinogeniculate projections were labeled by intraocular microinjections of cholera toxin-β (CTB) either conjugated to Alexa 488 (green) or 594 (red) administrated to the left and right eye, respectively. Pups were sacrificed 24 h after the last CTB injection. The results showed that ethanol exposure decreased the total number of dLGN neurons and significantly reduced the total dLGN projection as well as the contralateral and ipsilateral projection areas.
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8
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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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Pickering C, Wicher G, Rosendahl S, Schiöth HB, Fex-Svenningsen A. A low ethanol dose affects all types of cells in mixed long-term embryonic cultures of the cerebellum. Basic Clin Pharmacol Toxicol 2010; 106:472-8. [PMID: 20074269 DOI: 10.1111/j.1742-7843.2009.00528.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The beneficial effect of the '1-drink-a-day' lifestyle is suggested by studies of cardiovascular health, and this recommendation is increasingly followed in many countries. The main objective of this study was to determine whether this pattern of ethanol use would be detrimental to a pregnant woman. We exposed a primary culture of rat cerebellum from embryonic day 17 (corresponding to second trimester in humans) to ethanol at a concentration of 17.6 mM which is roughly equivalent to one glass of wine. Acutely, there was no change in cell viability after 5 or 8 days of exposure relative to control. By 11 days, a reduction in the number of viable cells was observed without an accompanying change in caspase-3 activity (marker of apoptotic cell death), suggesting changes in cell proliferation. As the proportion of nestin-positive cells was higher in the ethanol-treated cultures after 5 days, we hypothesized that an increase in differentiation to neurons would compensate for the ongoing neuronal death. However, there were limits to this compensatory ability as the relative proportion of nestin-positive cells was decreased after 11 days. To further illustrate the negative long-term effects of this ethanol dose, cultures were exposed for 30 days. After this period, virtually no neurons or myelinating oligodendrocytes were present in the ethanol-treated cultures. In conclusion, chronic exposure to ethanol, even at small doses, dramatically and persistently affects normal development.
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Affiliation(s)
- Chris Pickering
- Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden.
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Degeneration of Retinal Ganglion Cells After Optic Nerve Sheath Fenestration in an Experimental Rat Model. J Neuroophthalmol 2009; 29:275-80. [DOI: 10.1097/wno.0b013e3181a57ccf] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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DeMaman AS, Melo P, Homem JM, Tavares MA, Lachat JJ. Effectiveness of iron repletion in the diet for the optic nerve development of anaemic rats. Eye (Lond) 2009; 24:901-8. [DOI: 10.1038/eye.2009.205] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Effects of neonatal and peripubertal ethanol treatment on various aspects of adult rat behavior and brain anatomy. Int J Dev Neurosci 2009; 27:249-56. [PMID: 19437591 DOI: 10.1016/j.ijdevneu.2008.12.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Exposure to ethanol during critical stages of brain development and maturation has adverse effects on behavioral and cognitive functions. So far, most animal models focused on the effects of either pre- or early postnatal ethanol treatment on behavior. We here used a multiple crossover design to investigate the effects of neonatal (postnatal day 7) ethanol treatment (2.5 g/kg b.i.d., dissolved in saline), subchronic peripubertal (postnatal days 40-65) ethanol treatment (1.0 g/kg, dissolved in saline) and the combination of both on the performance of adult Wistar rats in a variety of behavioral tasks. We also assessed anatomical changes in limbic and cortical brain areas. No effects of either single or combined neonatal and pubertal ethanol treatment was found on prepulse inhibition of startle (PPI, a measure of sensorimotor gating), or on the acoustic startle response in the absence of prepulses. Peripubertal ethanol treatment reduced the explorative behavior in the open field. The breakpoint in a progressive ratio operant response task was increased in those rats that had received both neonatal and pubertal ethanol treatment, while the preference for palatable food used as reinforcer in this task was not affected. No treatment effects were found on object recognition memory. No treatment effects on anxiety-related behavior in the elevated plus maze were found, however, the anxiolytic effect of the prototypical benzodiazepine diazepam was enhanced in rats that had received peripubertal ethanol treatment. Additive effects of neonatal and pubertal ethanol treatments were found on behaviors related to spontaneous locomotor activity. Combined neonatal and pubertal ethanol treatment lead to a reduction of myelin sheaths in the prefrontal cortex, and the neonatal ethanol treatment lead to a reduced number of parvalbumine-immunoreactive cells in the dorsal hippocampus. These findings suggest that neonatal ethanol exposure increases the risk of some but not all adverse behavioral and brain anatomical effects of pubertal ethanol consumption.
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Dodge NC, Jacobson JL, Molteno CD, Meintjes EM, Bangalore S, Diwadkar V, Hoyme EH, Robinson LK, Khaole N, Avison MJ, Jacobson SW. Prenatal alcohol exposure and interhemispheric transfer of tactile information: Detroit and Cape Town findings. Alcohol Clin Exp Res 2009; 33:1628-37. [PMID: 19519722 DOI: 10.1111/j.1530-0277.2009.00994.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Previous research has demonstrated that heavy prenatal alcohol exposure affects the size and shape of the corpus callosum (CC) and compromises interhemispheric transfer of information. The aim of this study was to confirm the previous reports of poorer performance on a finger localization test (FLT) of interhemispheric transfer in a cohort of heavily exposed children and to extend these findings to a cohort of moderately exposed young adults. METHODS In Study 1, the FLT was administered to 40 heavily exposed and 23 nonexposed children from the Cape Coloured community of Cape Town, South Africa, who were evaluated for fetal alcohol syndrome (FAS) dysmorphology and growth. Anatomical images of the CC were obtained using structural MRI on a subset of these children. In Study 2, the FLT was administered to a cohort of 85 moderate-to-heavily exposed young adults participating in a 19-year follow-up assessment of the Detroit Prenatal Alcohol Exposure cohort, whose alcohol exposure had been ascertained prospectively during gestation. RESULTS In Study 1, children with FAS showed more transfer-related errors than controls after adjustment for confounding, and increased transfer-related errors were associated with volume reductions in the isthmus and splenium of the CC. In Study 2, transfer-related errors were associated with quantity of alcohol consumed per occasion during pregnancy. More errors were made if the mother reported binge drinking (> or =5 standard drinks) during pregnancy than if she drank regularly (M > or = 1 drink/day) without binge drinking. CONCLUSIONS These findings confirm a previous report of impaired interhemispheric transfer of tactile information in children heavily exposed to alcohol in utero and extend these findings to show that these deficits are also seen in more moderately exposed individuals, particularly those exposed to binge-like pregnancy drinking.
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Affiliation(s)
- Neil C Dodge
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI 48207, USA
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14
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Todorich B, Pasquini JM, Garcia CI, Paez PM, Connor JR. Oligodendrocytes and myelination: The role of iron. Glia 2009; 57:467-78. [PMID: 18837051 DOI: 10.1002/glia.20784] [Citation(s) in RCA: 414] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Bozho Todorich
- Department of Neurosurgery, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033-0850, USA
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15
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Miki T, Yokoyama T, Sumitani K, Kusaka T, Warita K, Matsumoto Y, Wang ZY, Wilce PA, Bedi KS, Itoh S, Takeuchi Y. Ethanol neurotoxicity and dentate gyrus development. Congenit Anom (Kyoto) 2008; 48:110-7. [PMID: 18778455 DOI: 10.1111/j.1741-4520.2008.00190.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Maternal alcohol ingestion during pregnancy adversely affects the developing fetus, often leading to fetal alcohol syndrome (FAS). One of the most severe consequences of FAS is brain damage that is manifested as cognitive, learning, and behavioral deficits. The hippocampus plays a crucial role in such abilities; it is also known as one of the brain regions most vulnerable to ethanol-induced neurotoxicity. Our recent studies using morphometric techniques have further shown that ethanol neurotoxicity appears to affect the development of the dentate gyrus in a region-specific manner; it was found that early postnatal ethanol exposure causes a transitory deficit in the hilus volume of the dentate gyrus. It is strongly speculated that such structural modifications, even transitory ones, appear to result in developmental abnormalities in the brain circuitry and lead to the learning disabilities observed in FAS children. Based on reports on possible factors deciding ethanol neurotoxicity to the brain, we review developmental neurotoxicity to the dentate gyrus of the hippocampal formation.
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Affiliation(s)
- Takanori Miki
- Department of Anatomy and Neurobiology, Faculty of Medicine, Kagawa University, Kagawa, Japan.
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16
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McGough NNH, Thomas JD, Dominguez HD, Riley EP. Insulin-like growth factor-I mitigates motor coordination deficits associated with neonatal alcohol exposure in rats. Neurotoxicol Teratol 2008; 31:40-8. [PMID: 18755266 DOI: 10.1016/j.ntt.2008.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Revised: 03/18/2008] [Accepted: 08/02/2008] [Indexed: 01/22/2023]
Abstract
Prenatal alcohol exposure can affect brain development, leading to behavioral problems, including overactivity, motor dysfunction and learning deficits. Despite warnings about the effects of drinking during pregnancy, rates of fetal alcohol syndrome remain unchanged and thus, there is an urgent need to identify interventions that reduce the severity of alcohol's teratogenic effects. Insulin-like growth factor-I (IGF-I) is neuroprotective against ethanol-related toxicity and promotes white matter production following a number of insults. Given that prenatal alcohol leads to cell death and white matter deficits, the present study examined whether IGF-I could reduce the severity of behavioral deficits associated with developmental alcohol exposure. Sprague-Dawley rat pups received ethanol intubations (5.25 g/kg/day) or sham intubations on postnatal days (PD) 4-9, a period of brain development equivalent to the third trimester. On PD 10-13, subjects from each treatment received 0 or 10 microg IGF-I intranasally each day. Subjects were then tested on a series of behavioral tasks including open field activity (PD 18-21), parallel bar motor coordination (PD 30-32) and Morris maze spatial learning (PD 45-52). Ethanol exposure produced overactivity, motor coordination impairments, and spatial learning deficits. IGF-I treatment significantly mitigated ethanol's effects on motor coordination, but not on the other two behavioral tasks. These data indicate that IGF-I may be a potential treatment for some of ethanol's damaging effects, a finding that has important implications for children of women who drink alcohol during pregnancy.
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Affiliation(s)
- Nancy N H McGough
- Department of Psychology, San Diego State University, San Diego, CA 92120, USA
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17
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Correlation of axon size and myelin occupancy in rats prenatally exposed to methamphetamine. Brain Res 2008; 1222:61-8. [PMID: 18585694 DOI: 10.1016/j.brainres.2008.05.047] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Revised: 10/30/2007] [Accepted: 05/19/2008] [Indexed: 11/24/2022]
Abstract
The abuse of methamphetamine (MA) and other psychostimulants is a social and medical problem. In particular, the use of these drugs by pregnant women results in an increased number of children exposed prenatally to psychostimulants. Our previous work has demonstrated that prenatal exposure to MA affects the normal development of the rat visual system due to alterations of biochemical mechanisms and oxidative stress. It was also demonstrated that prenatal exposure to MA affects the dopaminergic system of the rat retina and optic nerve (ON) myelination. The present work was conducted to evaluate the effects of prenatal exposure to MA on the development of the ON in terms of axon growth and the myelin sheath. Pregnant female rats were given 5 mg/kg/day MA, subcutaneously (s.c.), in 0.9% saline from gestational day (GD) 8 to 22. The pair-fed control group was injected s.c. with an isovolumetric dose of 0.9% saline. Qualitative analysis was performed using representative electron ultramicrographs. Quantitative analysis was performed at an electron microscopic level on ON cross sections; parameters measured included myelinated/unmyelinated ratio, outer axon mean area, inner axon mean area, myelin mean area, myelin occupancy and distribution of axons by size. The ON of prenatally MA-exposed rats presented a higher rate of deformed axons and slighter lamellar separation. At PND 21, the average outer axon area of MA-treated males was significantly reduced. The average inner axon area only showed a significant difference between MA and control males for axons with an area of less than 0.3 microm(2). The average myelin area of MA-treated males was significantly reduced, and in MA-treated females was only significantly reduced in axons with an area of less than 0.3 microm(2). The percentage of myelin occupancy was significantly affected in MA-treated males, and in MA-treated females in the group of axons with an area of more than 0.3 microm(2). At PND 14 no significant differences were found between MA and control groups. The spectrum of ON myelinated axon size of MA-treated animals was shifted to the left at PND 14 and PND 21 for both genders. These results are in agreement with previous animal studies of prenatal and perinatal exposure to drugs of abuse. Taken together, these data indicate that the ON is vulnerable to early exposure to MA which causes developmental changes and may interfere with the functioning of the visual system.
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18
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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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Li Z, Dong T, Pröschel C, Noble M. Chemically diverse toxicants converge on Fyn and c-Cbl to disrupt precursor cell function. PLoS Biol 2007; 5:e35. [PMID: 17298174 PMCID: PMC1790953 DOI: 10.1371/journal.pbio.0050035] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Accepted: 12/04/2006] [Indexed: 12/29/2022] Open
Abstract
Identification of common mechanistic principles that shed light on the action of the many chemically diverse toxicants to which we are exposed is of central importance in understanding how toxicants disrupt normal cellular function and in developing more effective means of protecting against such effects. Of particular importance is identifying mechanisms operative at environmentally relevant toxicant exposure levels. Chemically diverse toxicants exhibit striking convergence, at environmentally relevant exposure levels, on pathway-specific disruption of receptor tyrosine kinase (RTK) signaling required for cell division in central nervous system (CNS) progenitor cells. Relatively small toxicant-induced increases in oxidative status are associated with Fyn kinase activation, leading to secondary activation of the c-Cbl ubiquitin ligase. Fyn/c-Cbl pathway activation by these pro-oxidative changes causes specific reductions, in vitro and in vivo, in levels of the c-Cbl target platelet-derived growth factor receptor-α and other c-Cbl targets, but not of the TrkC RTK (which is not a c-Cbl target). Sequential Fyn and c-Cbl activation, with consequent pathway-specific suppression of RTK signaling, is induced by levels of methylmercury and lead that affect large segments of the population, as well as by paraquat, an organic herbicide. Our results identify a novel regulatory pathway of oxidant-mediated Fyn/c-Cbl activation as a shared mechanism of action of chemically diverse toxicants at environmentally relevant levels, and as a means by which increased oxidative status may disrupt mitogenic signaling. These results provide one of a small number of general mechanistic principles in toxicology, and the only such principle integrating toxicology, precursor cell biology, redox biology, and signaling pathway analysis in a predictive framework of broad potential relevance to the understanding of pro-oxidant–mediated disruption of normal development. Chemically different toxins (lead, methylmercury, and paraquat) each cause the intracellular environment to become more oxidized, and thereby activate a common pathway that suppresses signaling from growth factor receptors that may be associated with developmental impairments. Discovering general principles underlying the effects of toxicant exposure on biological systems is one of the central challenges of toxicological research. We have discovered a previously unrecognized regulatory pathway on which chemically diverse toxicants converge, at environmentally relevant exposure levels, to disrupt the function of progenitor cells of the developing central nervous system. We found that the ability of low levels of methylmercury, lead, and paraquat to make progenitor cells more oxidized causes activation of an enzyme called Fyn kinase. Activated Fyn then activates another enzyme (c-Cbl) that modifies specific proteins—receptors that are required for cell division and survival—to initiate the proteins' degradation. By enhancing degradation of these receptors, their downstream signaling functions are repressed. Analysis of developmental exposure to methylmercury provided evidence that this same pathway is activated in vivo by environmentally relevant toxicant levels. The remarkable sensitivity of progenitor cells to low levels of toxicant exposure, and the discovery of the redox/Fyn/c-Cbl pathway as a mechanism by which small increases in oxidative status can markedly alter cell function, provide a novel and specific means by which exposure to chemically diverse toxicants might perturb normal development. In addition, the principles revealed in our studies appear likely to have broad applicability in understanding the regulation of cell function by alterations in redox balance, regardless of how they might be generated.
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Affiliation(s)
- Zaibo Li
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Tiefei Dong
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Chris Pröschel
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Mark Noble
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, New York, United States of America
- * To whom correspondence should be addressed. E-mail:
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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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Melo P, Moreno VZ, Vázquez SP, Pinazo-Durán MD, Tavares MA. Myelination changes in the rat optic nerve after prenatal exposure to methamphetamine. Brain Res 2006; 1106:21-29. [PMID: 16842764 DOI: 10.1016/j.brainres.2006.05.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2006] [Revised: 05/05/2006] [Accepted: 05/08/2006] [Indexed: 11/19/2022]
Abstract
The use of psychostimulants during adolescence and early adult life has increased in recent years. It is known that these substances affect the sensory systems, and the optic nerve has been shown to be a target tissue. This work was conducted to evaluate the effects of prenatal exposure to methamphetamine (MA) on the developmental pattern of the rat optic nerve. Pregnant female rats were given 5 mg/kg body weight/day MA, s.c., in 0.9% saline from gestational days 8 to 22. The control group was injected with an isovolumetric dose of 0.9% saline. Animal model parameters, such as gestational body weight evolution, food intake and pups parameters were registered. The offspring were sacrificed at postnatal days (PND) 7, 14 and 21. Morphometric analyses were performed at light and electron microscopic levels on optic nerve cross sections; parameters measured included optic nerve diameter and area, axonal density, total number of axons and myelin thickness. Myelin basic protein (MBP) was measured by western blotting in optic nerve samples at PND14 and PND21. The animal model parameters, such as maternal and pup weight, showed no significant differences between MA and control groups. Optic nerve diameter was smaller at PND7 in the male MA group and in both male and female MA groups at PND21. The mean cross-sectional area was smaller at PND14 in the male MA group and in both male and female groups at PND21. The total number of myelinated axons did not vary between groups at any of the studied ages. The myelin thickness of the axons in MA-treated females was thinner when compared with the respective control group at PND21. No other differences were found concerning myelin thickness. There was a reduction of MBP protein expression in MA-injected females at PND14 and PND21. The combined results suggest that prenatal exposure to MA affects the myelination process.
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Affiliation(s)
- Pedro Melo
- Institute of Anatomy Professor J. A. Pires da Silva, Faculty of Medicine of the University of Porto, Alameda Hernâni Monteiro, 4200-319 Porto, Portugal; Institute for Molecular and Cell Biology, Porto, Portugal.
| | - Vicente Zanón Moreno
- Ophthalmology Research Unit "Santiago Grisolia", University Hospital Doctor Peset, Valencia, Spain
| | - Sheila Pons Vázquez
- Ophthalmology Research Unit "Santiago Grisolia", University Hospital Doctor Peset, Valencia, Spain
| | | | - Maria Amélia Tavares
- Institute of Anatomy Professor J. A. Pires da Silva, Faculty of Medicine of the University of Porto, Alameda Hernâni Monteiro, 4200-319 Porto, Portugal; Institute for Molecular and Cell Biology, Porto, Portugal.
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Melo P, Rodrigues LG, Pinazo-Durán MD, Tavares MA. Methamphetamine and lipid peroxidation in the rat retina. ACTA ACUST UNITED AC 2005; 73:455-60. [PMID: 15880787 DOI: 10.1002/bdra.20138] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND The use of psychoactive drugs during adolescence and early adult life has increased in the last few decades. It is known that developmental exposure to psychostimulants affects the sensory systems, and the retina has been shown to be a target tissue. This work was conducted to evaluate the pattern of lipid peroxidation in the rat retina following prenatal exposure to methamphetamine (MA). METHODS Pregnant female Wistar rats were given MA (5 mg/kg of body weight/day; SC, in 0.9% saline) from GD 8 to 22. Offspring were sacrificed at postnatal days (PNDs) 7, 14, and 21. The retinas were homogenized, and both the total antioxidant and superoxide dismutase (SOD) activities were measured by enzymatic-colorimetric methods. The lipid peroxidation byproducts (malondialdehyde [MDA] and MDA-like metabolites) were measured by the thiobarbituric acid test. RESULTS Total antioxidant levels were lower in the MA group at PND 21 in both males and females. The activity of SOD was higher in PND 7 females from the MA group. MDA levels were higher in the MA group at PND 21 in both genders. CONCLUSIONS These findings suggest that prenatal-induced MA toxicity in the retina may be related to lipid peroxidation processes and oxidative stress.
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Affiliation(s)
- Pedro Melo
- Institute of Anatomy, Faculty of Medicine, University of Porto, Alameda Hernâni Monteiro, 4200-319 Porto, Portugal
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Allen GC, Farnell YZ, Maeng JU, West JR, Chen WJA, Earnest DJ. Long-term effects of neonatal alcohol exposure on photic reentrainment and phase-shifting responses of the activity rhythm in adult rats. Alcohol 2005; 37:79-88. [PMID: 16584971 PMCID: PMC2695981 DOI: 10.1016/j.alcohol.2005.11.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Revised: 11/08/2005] [Accepted: 11/18/2005] [Indexed: 11/24/2022]
Abstract
In rats, neonatal alcohol (EtOH) exposure coinciding with the period of rapid brain growth produces structural damage in some brain regions that often persists into adulthood and thus may have long-term consequences in the neural regulation of behavior. Because recent findings indicate that the circadian clock located in the rat suprachiasmatic nucleus is vulnerable to alcohol-induced insults during development, the present study examined the long-term effects of neonatal alcohol exposure on the photic regulation of circadian behavior in adult rats. Rat pups were exposed to alcohol (3.0, 4.5, or 6.0 g x kg(-1) x day(-1)) or isocaloric milk formula on postnatal days 4-9 using artificial-rearing methods. At 2 months of age, animals were housed individually and circadian wheel-running behavior was continuously analyzed to determine the effects of neonatal alcohol treatment on the rate of reentrainment to a 6-h advance in the 12-h light:12-h dark photoperiod and the phase-shifting properties of free-running rhythms in response to discrete light pulses on a background of constant darkness. For all doses, neonatal alcohol exposure had a significant effect in reducing the time for reentrainment such that EtOH-treated rats required four to five fewer days than control animals for stable realignment of the activity rhythm to the shifted light-dark cycle. Coupled with the accelerated rate of reentrainment, the amplitude of light-evoked phase delays at circadian time 14 and advances at circadian time 22 in the 4.5 and 6.0 g x kg(-1) x day(-1) EtOH groups was almost twofold greater than that observed in control animals. The present observations indicate that the mechanisms by which photic signals regulate circadian behavior are permanently altered following alcohol exposure during the period of rapid brain development. These long-term alterations in the photic regulation of circadian rhythms may account, at least partially, for some neurobehavioral consequences of prenatal alcohol exposure in humans such as depression.
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Affiliation(s)
- Gregg C Allen
- Department of Human Anatomy and Medical Neurobiology, The Texas A&M University System Health Science Center, College of Medicine, 228 Reynolds Medical Building, College Station, TX 77843-1114, USA
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Ray B, Roy TS, Wadhwa S, Roy KK. Development of the human fetal cochlear nerve: a morphometric study. Hear Res 2005; 202:74-86. [PMID: 15811701 DOI: 10.1016/j.heares.2004.09.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2004] [Accepted: 09/30/2004] [Indexed: 10/26/2022]
Abstract
Ontogenesis of the human peripheral auditory pathway is relatively less explored. While the distal part of the auditory perception apparatus (i.e. the cochlea) received attention, studies on the neural element carrying information to the brainstem (i.e. the cochlear nerve) are scarce. In the present study, axonal differentiation, maturation and myelination of the distal end of the human cochlear nerve (CN) were assessed using light and electron microscopy. Seven human fetuses of 12, 15, 18, 20, 22, 28 and 38 weeks' gestation (WG) were analyzed. Light microscopy revealed nerve fascicles as early as 12 WG, initially arranged loosely but later compacted by 18 WG. Myelinated fibers were clearly detected at 28 WG. Ultrastructurally, at 12 WG developing Schwann cells were present between the thin unmyelinated axons. At 15 WG, the fascicular arrangement was distinct with blood vessels in the perineurium. The maximum number of axons was found at 20 WG, which subsequently reduced to reach the adult level at 22 WG. The myelinated axons in the CN were first observed on the left side at 20 WG, following which the number and proportion of myelinated axons increased until term, incorporating both small and large axons. The right CN lagged behind in maturation. Axon size also increased with age. Thus, the maturation of the human CN commences during the mid-gestation period and produces exuberant axons that are eventually pruned at a time when axons start to myelinate. During this developmental period the human CN maintains maturational asymmetry, the functional consequences of which remain to be elucidated.
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Affiliation(s)
- Bappaditya Ray
- Department of Anatomy, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
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Bartzokis G. BRAIN MYELINATION IN PREVALENT NEUROPSYCHIATRIC DEVELOPMENTAL DISORDERS: PRIMARY AND COMORBID ADDICTION. ADOLESCENT PSYCHIATRY 2005; 29:55-96. [PMID: 18668184 PMCID: PMC2490819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Current concepts of addiction focus on neuronal neurocircuitry and neurotransmitters and are largely based on animal model data, but the human brain is unique in its high myelin content and extended developmental (myelination) phase that continues until middle age. The biology of our exceptional myelination process and factors that influence it have been synthesized into a recently published myelin model of human brain evolution and normal development that cuts across the current symptom-based classification of neuropsychiatric disorders.The developmental perspective of the model suggests that dysregulations in the myelination process contribute to prevalent early-life neuropsychiatric disorders, as well as to addictions. These disorders share deficits in inhibitory control functions that likely contribute to their high rates of comorbidity with addiction and other impulsive behaviors. The model posits that substances such as alcohol and psychostimulants are toxic to the extremely vulnerable myelination process and contribute to the poor outcomes of primary and comorbid addictive disorders in susceptible individuals.By increasing the scientific focus on myelination, the model provides a rational biological framework for the development of novel, myelin-centered treatments that may have widespread efficacy across multiple disease states and could potentially be used in treating, delaying, or even preventing some of the most prevalent and devastating neuropsychiatric disorders.
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Medina AE, Krahe TE, Ramoa AS. Early alcohol exposure induces persistent alteration of cortical columnar organization and reduced orientation selectivity in the visual cortex. J Neurophysiol 2004; 93:1317-25. [PMID: 15483067 DOI: 10.1152/jn.00714.2004] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Fetal alcohol syndrome (FAS) is a major cause of learning and sensory deficits in children. The visual system in particular is markedly affected, with an elevated prevalence of poor visual perceptual skills. Developmental problems involving the neocortex are likely to make a major contribution to some of these abnormalities. Neuronal selectivity to stimulus orientation, a functional property thought to be crucial for normal vision, may be especially vulnerable to alcohol exposure because it starts developing even before eye opening. To address this issue, we examined the effects of early alcohol exposure on development of cortical neuron orientation selectivity and organization of cortical orientation columns. Ferrets were exposed to ethanol starting at postnatal day (P) 10, when the functional properties and connectivity of neocortical neurons start to develop. Alcohol exposure ended at P30, just before eye opening at P32. Following a prolonged alcohol-free period (15-35 days), long-term effects of early alcohol exposure on cortical orientation selectivity were examined at P48-P65, when orientation selectivity in normal ferret cortex has reached a mature state. Optical imaging of intrinsic signals revealed decreased contrast of orientation maps in alcohol- but not saline-treated animals. Moreover, single-unit recordings revealed that early alcohol treatment weakened neuronal orientation selectivity while preserving robust visual responses. These findings indicate that alcohol exposure during a brief period of development disrupts cortical processing of sensory information at a later age and suggest a neurobiological substrate for some types of sensory deficits in FAS.
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Affiliation(s)
- Alexandre E Medina
- Deptartment of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, Box 0709, 1101 East Marshall St., Rm. 12-042, Richmond, VA 23298-0709, USA
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Bartzokis G. Age-related myelin breakdown: a developmental model of cognitive decline and Alzheimer's disease. Neurobiol Aging 2004; 25:5-18; author reply 49-62. [PMID: 14675724 DOI: 10.1016/j.neurobiolaging.2003.03.001] [Citation(s) in RCA: 659] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A hypothetical model of Alzheimer's disease (AD) as a uniquely human brain disorder rooted in its exceptional process of myelination is presented. Cortical regions with the most protracted development are most vulnerable to AD pathology, and this protracted development is driven by oligodendrocytes, which continue to differentiate into myelin producing cells late into the fifth decade of life. The unique metabolic demands of producing and maintaining their vast myelin sheaths and synthesizing the brain's cholesterol supply make oligodendrocytes especially susceptible to a variety of insults. Their vulnerability increases with increasing age at differentiation as later-differentiating cells myelinate increasing numbers of axonal segments. These vulnerable late-differentiating cells drive the protracted process of intracortical myelination and by increasing local cholesterol and iron levels, progressively increase the toxicity of the intracortical environment forming the basis for the age risk factor for AD. At older ages, the roughly bilaterally symmetrical continuum of oligodendrocyte vulnerability manifests as a progressive pattern of myelin breakdown that recapitulates the developmental process of myelination in reverse. The ensuing homeostatic responses to myelin breakdown further increase intracortical toxicity and results in the relentless progression and non-random anatomical distribution of AD lesions that eventually cause neuronal dysfunction and degeneration. This process causes a slowly progressive disruption of neural impulse transmission that degrades the temporal synchrony of widely distributed neural networks underlying normal brain function. The resulting network "disconnections" first impact functions that are most dependent on large-scale synchronization including higher cognitive functions and formation of new memories. Multiple genetic and environmental risk factors (e.g. amyloid beta-peptide and free radical toxicity, head trauma, anoxia, cholesterol levels, etc.) can contribute to the cognitive deficits observed in aging and AD through their impact on the life-long trajectory of myelin development and breakdown. This development-to-degeneration model is testable through imaging and post mortem methods and highlights the vital role of myelin in impulse transmission and synchronous brain function. The model offers a framework that explains the anatomical distribution and progressive course of AD pathology, some of the failures of promising therapeutic interventions, and suggests further testable hypotheses as well as novel approaches for intervention efforts.
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Affiliation(s)
- George Bartzokis
- Department of Neurology, UCLA Alzheimer's Disease Center, Los Angeles, CA 90095, USA.
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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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Sawada K, Sakata-Haga H, Komatsu S, Ohta K, Jeong YG, Fukui Y. A selective loss of small-diameter myelinated optic nerve axons in rats prenatally exposed to ethanol. Congenit Anom (Kyoto) 2002; 42:125-9. [PMID: 12196709 DOI: 10.1111/j.1741-4520.2002.tb00861.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pregnant rats were fed an ethanol-containing liquid diet between gestational days 10 and 21. The optic nerves of their litters at 49 days of age were examined using quantitative stereological procedures. Cross-sectional areas of the optic nerve in ethanol-exposed rats were significantly smaller than those in controls. This was reflected in the reduced number of myelinated fibers, but not of non-myelinated fibers. The size distribution histogram indicated a decreased number of small axonal-diameter myelinated fibers in ethanol-exposed rats. The results suggested optic nerve hypoplasia in ethanol-exposed rats characterized by a selective loss of small-diameter myelinated fibers.
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Affiliation(s)
- Kazuhiko Sawada
- Department of Anatomy and Developmental Neurobiology, University of Tokushima School of Medicine, Japan.
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