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Erguven P, Sevgin K, Kotil T, Kaleci B, Caglar HG, Ozer OF. Continuous Thymoquinone Administration Mitigates Sodium Iodate-Induced Retinal Degeneration in Rats. Curr Eye Res 2024:1-9. [PMID: 39039707 DOI: 10.1080/02713683.2024.2381203] [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: 01/24/2024] [Accepted: 07/12/2024] [Indexed: 07/24/2024]
Abstract
PURPOSE This study aimed to investigate the protective or therapeutic effect of thymoquinone (TQ) in a retinal degeneration rat model and its relationships with the retina ultrastructure, heme oxygenase 1 (HO-1), caspase-3, and RPE65 expressions and to determine whether TQ has a therapeutic effect at the biochemical level. METHODS A total of 25 adult Wistar albino rats were divided into the following treatment groups: saline (control: CONT), CO (corn oil), sodium iodate (SI), TQ + SI, and SI + TQ injection groups. Retina morphology, RPE65, HO-1, and caspase-3 expression levels were evaluated using immunohistochemistry, and optical density was determined using ImageJ. Ultrastructural evaluations were performed with electron microscopy. Thiol-disulfide homeostatic parameters were examined in serum samples. RESULTS Outer nuclear layer (ONL) thickness was significantly higher in the SI + TQ group compared to the SI group. The RPE65 expression significantly decreased in the SI group compared with the CONT and CO groups. A significant increase in RPE65 expression level and a significant decrease in caspase-3 expression level were found in the SI + TQ group compared with the SI group. The increase in HO-1 expression level was significantly higher in the TQ treatment groups, particularly in the SI + TQ group. In the SI and TQ + SI groups, the ONL thickness significantly decreased with a significant increase in caspase-3 expression compared to the CONT and CO groups. In the treatment groups, decreased organelle damage was observed on electron microscopy. In the SI + TQ group, the disulfide/native thiol and disulfide/total thiol ratios were significantly lower than all other groups, while the native/total thiol ratio was significantly higher than the other experimental groups. CONCLUSIONS The present study provides evidence that continuous TQ treatment can increase HO-1 and RPE65 expression and decrease apoptosis (caspase-3 levels), thereby preserving the retina at the ultrastructural level. Moreover, TQ administration can maintain thiol/disulfide homeostasis in SI-induced retinal degeneration-modelled rats.
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Affiliation(s)
- Pelin Erguven
- Department of Histology and Embryology, International Faculty of Medicine, University of Health Sciences, Istanbul, Turkey
| | - Kubra Sevgin
- Department of Histology and Embryology, International Faculty of Medicine, University of Health Sciences, Istanbul, Turkey
| | - Tugba Kotil
- Department of Histology and Embryology, Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Belisa Kaleci
- Department of Nursing and Physiotherapy, Faculty of Medical Sciences, Albanian University, Tirana, Albania
| | | | - Omer Faruk Ozer
- Department of Medical Biochemistry, Faculty of Medicine, Bezmialem University, Istanbul, Turkey
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Espitia-Arias MD, de la Villa P, Paleo-García V, Germain F, Milla-Navarro S. Oxidative Model of Retinal Neurodegeneration Induced by Sodium Iodate: Morphofunctional Assessment of the Visual Pathway. Antioxidants (Basel) 2023; 12:1594. [PMID: 37627589 PMCID: PMC10451746 DOI: 10.3390/antiox12081594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/05/2023] [Accepted: 08/07/2023] [Indexed: 08/27/2023] Open
Abstract
Sodium iodate (NaIO3) has been shown to cause severe oxidative stress damage to retinal pigment epithelium cells. This results in the indirect death of photoreceptors, leading to a loss of visual capabilities. The aim of this work is the morphological and functional characterization of the retina and the visual pathway of an animal model of retinal neurodegeneration induced by oxidative stress. Following a single intraperitoneal dose of NaIO3 (65 mg/kg) to C57BL/6J mice with a mutation in the Opn4 gene (Opn4-/-), behavioral and electroretinographic tests were performed up to 42 days after administration, as well as retinal immunohistochemistry at day 57. A near total loss of the pupillary reflex was observed at 3 days, as well as an early deterioration of visual acuity. Behavioral tests showed a late loss of light sensitivity. Full-field electroretinogram recordings displayed a progressive and marked decrease in wave amplitude, disappearing completely at 14 days. A reduction in the amplitude of the visual evoked potentials was observed, but not their total disappearance. Immunohistochemistry showed structural alterations in the outer retinal layers. Our results show that NaIO3 causes severe structural and functional damage to the retina. Therefore, the current model can be presented as a powerful tool for the study of new therapies for the prevention or treatment of retinal pathologies mediated by oxidative stress.
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Affiliation(s)
- Michael D. Espitia-Arias
- Department of Systems Biology, University of Alcalá, 28805 Madrid, Spain; (M.D.E.-A.); (P.d.l.V.); (V.P.-G.)
| | - Pedro de la Villa
- Department of Systems Biology, University of Alcalá, 28805 Madrid, Spain; (M.D.E.-A.); (P.d.l.V.); (V.P.-G.)
- Visual Neurophysiology Group-Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), 28034 Madrid, Spain
| | - Victor Paleo-García
- Department of Systems Biology, University of Alcalá, 28805 Madrid, Spain; (M.D.E.-A.); (P.d.l.V.); (V.P.-G.)
| | - Francisco Germain
- Department of Systems Biology, University of Alcalá, 28805 Madrid, Spain; (M.D.E.-A.); (P.d.l.V.); (V.P.-G.)
- Visual Neurophysiology Group-Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), 28034 Madrid, Spain
| | - Santiago Milla-Navarro
- Department of Systems Biology, University of Alcalá, 28805 Madrid, Spain; (M.D.E.-A.); (P.d.l.V.); (V.P.-G.)
- Visual Neurophysiology Group-Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), 28034 Madrid, Spain
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Zhang N, Zhang X, Girardot PE, Chrenek MA, Sellers JT, Li Y, Kim YK, Summers VR, Ferdous S, Shelton DA, Boatright JH, Nickerson JM. Electrophysiologic and Morphologic Strain Differences in a Low-Dose NaIO3-Induced Retinal Pigment Epithelium Damage Model. Transl Vis Sci Technol 2021; 10:10. [PMID: 34251426 PMCID: PMC8287050 DOI: 10.1167/tvst.10.8.10] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Purpose We aimed to explore differences in the NaIO3-elicited responses of retinal pigment epithelium (RPE) and other retinal cells associated with mouse strains and dosing regimens. Methods One dose of NaIO3 at 10 or 15 mg/kg was given intravenously to adult male C57BL/6J and 129/SV-E mice. Control animals were injected with PBS. Morphologic and functional changes were characterized by spectral domain optical coherence tomography, electroretinography, histologic, and immunofluorescence techniques. Results Injection with 10 mg/kg of NaIO3 did not cause consistent RPE or retinal changes in either strain. Administration of 15 mg/kg of NaIO3 initially induced a large transient increase in scotopic electroretinography a-, b-, and c-wave amplitudes within 12 hours of injection, followed by progressive structural and functional degradation at 3 days after injection in C57BL/6J mice and at 1 week after injection in 129/SV-E mice. RPE cell loss occurred in a large posterior-central lesion with a ring-like transition zone of abnormally shaped cells starting 12 hours after NaIO3 treatment. Conclusions NaIO3 effects depended on the timing, dosage, and mouse strain. The RPE in the periphery was spared from damage compared with the central RPE. The large transient increase in the electroretinography was remarkable. Translational Relevance This study is a phase T1 translational research study focusing on the development and validation of a mouse model of RPE damage. It provides a detailed foundation for future research, informing choices of mouse strain, dosage, and time points to establish NaIO3-induced RPE damage.
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Affiliation(s)
- Nan Zhang
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA, USA.,Department of Ophthalmology, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xian Zhang
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA, USA.,Department of Ophthalmology, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Preston E Girardot
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA, USA
| | - Micah A Chrenek
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA, USA
| | - Jana T Sellers
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA, USA
| | - Ying Li
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA, USA
| | - Yong-Kyu Kim
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA, USA.,Department of Ophthalmology, Hallym University College of Medicine, Kangdong Sacred Heart Hospital, Seoul, South Korea
| | - Vivian R Summers
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA, USA
| | - Salma Ferdous
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA, USA
| | - Debresha A Shelton
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA, USA
| | - Jeffrey H Boatright
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA, USA.,Atlanta VA Center for Visual and Neurocognitive Rehabilitation, Decatur, GA, USA
| | - John M Nickerson
- Department of Ophthalmology, School of Medicine, Emory University, Atlanta, GA, USA
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Ultrastructural Changes and Expression of PCNA and RPE65 in Sodium Iodate-Induced Acute Retinal Pigment Epithelium Degeneration Model. Neurochem Res 2018; 43:1010-1019. [DOI: 10.1007/s11064-018-2508-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 03/14/2018] [Accepted: 03/16/2018] [Indexed: 01/30/2023]
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Fujii M, Sunagawa GA, Kondo M, Takahashi M, Mandai M. Evaluation of micro Electroretinograms Recorded with Multiple Electrode Array to Assess Focal Retinal Function. Sci Rep 2016; 6:30719. [PMID: 27480484 PMCID: PMC4969741 DOI: 10.1038/srep30719] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 07/06/2016] [Indexed: 12/23/2022] Open
Abstract
Full-field electroretinograms (ERGs) are used to objectively assess the mass function of the retina, whereas focal ERGs are used to evaluate the focal retinal function. The purpose of this study was to determine the usefulness of a multiple electrode array (MEA) system for recording ex vivo micro ERGs (mERGs) together with multiunit spike responses of the retinal ganglion cells (RGCs) to assess focal retinal function in isolated mouse retinas. The a- and b-waves of the full-field ERGs were present in the mERG. The b-wave was blocked by L-AP4, an inhibitor of the mGluR6 receptor, and the OFF-component was blocked by exposure to PDA, an antagonist of ionotropic glutamate receptors, with a corresponding RGC responses. mERGs were also recorded from mice with progressive retinal degeneration, the C57BL/6J-Pde6brd1-2J/J (rd1) mice, from which conventional full-field ERGs are non-recordable. A blockade of the glutamate receptors indicated that the negative wave of rd1 mice do not originate from the photoreceptors but from the second or third order neurons. This technique of recording mERGs will be useful in assessing the focal properties of the retinas obtained from eyes with pathology and also to follow the recovery of the physiology of the retina in regenerative studies.
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Affiliation(s)
- Momo Fujii
- Laboratory for Retinal Regeneration, RIKEN Center for Developmental Biology, Kobe, 650-0047, Japan
| | - Genshiro A Sunagawa
- Laboratory for Retinal Regeneration, RIKEN Center for Developmental Biology, Kobe, 650-0047, Japan
| | - Mineo Kondo
- Department of Ophthalmology, Mie University Graduate School of Medicine, 2-174, Edobashi, Tsu, Mie, 514-8507, Japan
| | - Masayo Takahashi
- Laboratory for Retinal Regeneration, RIKEN Center for Developmental Biology, Kobe, 650-0047, Japan
| | - Michiko Mandai
- Laboratory for Retinal Regeneration, RIKEN Center for Developmental Biology, Kobe, 650-0047, Japan
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Cho BJ, Seo JM, Yu HG, Chung H. Monocular retinal degeneration induced by intravitreal injection of sodium iodate in rabbit eyes. Jpn J Ophthalmol 2016; 60:226-37. [PMID: 26902976 DOI: 10.1007/s10384-016-0429-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 12/22/2015] [Indexed: 01/10/2023]
Abstract
PURPOSE Our purpose was to evaluate the anatomical and functional changes in retinae of rabbit eyes following monocular intravitreal injection of sodium iodate (SI). METHODS Twenty albino rabbits were divided into four groups and underwent monocular intravitreal injection with four different doses of SI (0.1, 0.2, 0.4, and 0.8 mg). Before and for 28 days after injection, the eyes were examined using fundus photography, optical coherence tomography (OCT), and electroretinography (ERG). At postinjection days 2, 7, and 28, the eyes were enucleated and underwent histological examination. RESULTS On fundus examination, no distinct retinal changes were seen in any group except the 0.8-mg group, which showed chorioretinal vascular attenuation. In 0.1 and 0.2-mg groups, no significant anatomical changes were found except transient hyperreflective dots over the vitreoretinal interface on OCT. In 0.4 and 0.8-mg groups, disruption of the ellipsoid zone and diffuse retinal swelling were observed in the early period on OCT. In the 0.4-mg group, the outer retina was significantly destroyed at day 28, whereas the inner retina was relatively preserved. In the 0.8-mg group, the entire retina was destroyed irreversibly. The b-wave of ERG was reduced immediately in all groups, which recovered fully (0.1- and 0.2-mg groups), partially (0.4-mg group), or never (0.8-mg group). No structural or functional abnormalities were found in the fellow control eyes. CONCLUSIONS Retinal degeneration following intravitreal injection of SI appears to be dose dependent; retinal damage is reversible at low doses but irreversible at high doses. At a certain dose, the outer retina may be preferably ablated.
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Affiliation(s)
- Bum-Joo Cho
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea.,Seoul Artificial Eye Center, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea.,Department of Ophthalmology, Chuncheon Sacred Heart Hospital, Hallym University College of Medicine, Chuncheon, Gangwon-do, Korea
| | - Jong-Mo Seo
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea.,Seoul Artificial Eye Center, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea.,Department of Electrical and Computer Engineering, Seoul National University, Seoul, Korea
| | - Hyeong Gon Yu
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea.,Seoul Artificial Eye Center, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea
| | - Hum Chung
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea. .,Seoul Artificial Eye Center, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea. .,Department of Ophthalmology, Chung-Ang University Hospital, Seoul, Korea.
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Harada T, Machida S, Nishimura T, Kurosaka D. Contribution of N-methyl-DL-aspartic acid (NMDA)-sensitive neurons to generating oscillatory potentials in Royal College of Surgeons rats. Doc Ophthalmol 2013; 127:131-40. [PMID: 23744447 DOI: 10.1007/s10633-013-9394-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 05/28/2013] [Indexed: 11/29/2022]
Abstract
PURPOSE We investigated how the N-methyl-DL-aspartic acid (NMDA) receptor contributes to generating oscillatory potentials (OPs) of the electroretinogram (ERG) in the Royal College of Surgeons (RCS) rat. METHODS Scotopic ERGs were recorded from dystrophic and wild-type congenic (WT) RCS rats (n = 20 of each) at 25, 30, 35, and 40 days of age. The stimulus intensity was increased from -2.82 to 0.71 log cd-s/m(2) to obtain intensity-response function. NMDA was injected into the vitreous cavity of the right eyes. The left eyes were injected with saline as controls. The P3 obtained by a-wave fitting was digitally subtracted from the scotopic ERG to isolate the P2. For the OPs, the P2 was digitally filtered between 65 and 500 Hz. The amplitudes of OP1, OP2, OP3, and OP4 were then measured and summed and designated as ΣOPs. The implicit times of OP1, OP2, and OP3 were also measured. The frequency spectra of the OPs were analyzed using fast Fourier transform (FFT). RESULTS The maximum ERG a- and b-waves as well as ΣOPs amplitudes reduced with age in dystrophic rats. Compared with intravitreal saline injection, administration of NMDA decreased ΣOPs amplitudes from 30 days of age in dystrophic rats, while it did not attenuate ΣOPs amplitudes in WT rats. The implicit times of the OPs of the maximum ERG were prolonged by NMDA injections in WT and dystrophic rats. NMDA/saline ratios of ΣOPs amplitudes area under the FFT curves were significantly lower in dystrophic rats from 30 days of age than that in WT rats. CONCLUSION In the early stage of photoreceptor degeneration, intravitreal NMDA injection attenuated OPs amplitudes in dystrophic rats. This indicates that NMDA receptors play a significant role in generating OPs amplitudes with advancing photoreceptor degeneration.
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Affiliation(s)
- Tomomi Harada
- Departments of Ophthalmology, Iwate Medical University School of Medicine, 19-1 Uchimaru, Morioka, Iwate, 020-8505, Japan
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Machalińska A, Lubiński W, Kłos P, Kawa M, Baumert B, Penkala K, Grzegrzółka R, Karczewicz D, Wiszniewska B, Machaliński B. Sodium iodate selectively injuries the posterior pole of the retina in a dose-dependent manner: morphological and electrophysiological study. Neurochem Res 2010; 35:1819-27. [PMID: 20725778 PMCID: PMC2957578 DOI: 10.1007/s11064-010-0248-6] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/10/2010] [Indexed: 11/30/2022]
Abstract
Sequential morphological and functional features of retinal damage in mice exposed to different doses (40 vs. 20 mg/kg) of sodium iodate (NaIO3) were analyzed. Retinal morphology, apoptosis (TUNEL assay), and function (electroretinography; ERG) were examined at several time points after NaIO3 administration. The higher dose of NaIO3 caused progressive degeneration of the whole retinal area and total suppression of scotopic and photopic ERG. In contrast, the lower dose induced much less severe degeneration in peripheral part of retina along with a moderate decline of b- and a-wave amplitudes in ERG, corroborating the presence of regions within retina that retain their function. The peak of photoreceptor apoptosis was found on the 3rd day, but the lower dose induced more intense reaction within the central retina than in its peripheral region. In conclusion, these results indicate that peripheral area of the retina reveals better resistance to NaIO3 injury than its central part.
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Affiliation(s)
- Anna Machalińska
- Department of Histology and Embryology, Pomeranian Medical University, Szczecin, Poland.
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Redfern WS, Storey S, Tse K, Hussain Q, Maung KP, Valentin JP, Ahmed G, Bigley A, Heathcote D, McKay JS. Evaluation of a convenient method of assessing rodent visual function in safety pharmacology studies: effects of sodium iodate on visual acuity and retinal morphology in albino and pigmented rats and mice. J Pharmacol Toxicol Methods 2010; 63:102-14. [PMID: 20619348 DOI: 10.1016/j.vascn.2010.06.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2009] [Revised: 06/04/2010] [Accepted: 06/29/2010] [Indexed: 11/13/2022]
Abstract
INTRODUCTION We have evaluated the ability of a semi-automated, optomotor reflex method to assess drug-induced visual dysfunction, in albino and pigmented rats and mice. METHODS Male Han Wistar (HW) and Long Evans (LE) rats and mice (CD-1 and C57BL/6) were tested in a chamber formed by 4 computer monitors displaying a rotating vertical grating, to elicit head-tracking movements. The highest visible grating frequency was taken as the threshold of visual acuity, in cycles per degree (c/d). Animals received an intravenous infusion of either sodium iodate (50mg/kg) or 0.9% w/v NaCl (aq). They were tested 2h later, then re-tested daily for a further 3 days. The time course of the effect was assessed in HW rats over a 6-week period, including electron microscopy, and immunohistochemical analysis of markers of injury and repair in the retina. RESULTS Baseline visual acuities for HW and LE rats were 0.355 ± 0.007 and 0.530 ± 0.004 c/d, respectively, and 0.296 ± 0.003 c/d and 0.370 ± 0.001 c/d for CD-1 and C57BL/6 mice, respectively (n=10 for each). In HW rats there was a dramatic loss of visual acuity 2h after administration of sodium iodate (0.021 ± 0.021 c/d; P<0.001). Less dramatic decreases in visual acuity were seen in LE rats and in the two mouse strains. In HW rats, visual acuity was restored after 4 weeks. This paralleled the histopathological recovery of the peripheral retina, whereas the central retina did not recover. DISCUSSION The method proved to be very convenient, and the stability of visual acuity in vehicle control rats over a 6-week period also demonstrated its suitability for inclusion in long-term toxicity studies. Both albino and pigmented mice and rats are suitable for assessment of retinotoxicity using this method, but albino rats are the most sensitive to sodium iodate.
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Affiliation(s)
- William S Redfern
- Safety Pharmacology Departmen, Safety Assessment UK, AstraZeneca R&D, Alderley Park, Cheshire SK10 4TG, United Kingdom.
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Ohtaka K, Machida S, Ohzeki T, Tanaka M, Kurosaka D, Masuda T, Ishii T. Protective Effect of Hepatocyte Growth Factor Against Degeneration of the Retinal Pigment Epithelium and Photoreceptor in Sodium Iodate–Injected Rats. Curr Eye Res 2009; 31:347-55. [PMID: 16603468 DOI: 10.1080/02713680600629797] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
PURPOSE To investigate the possible protective effect of hepatocyte growth factor (HGF) against degeneration of photoreceptors and retinal pigment epithelium (RPE) in vivo. METHODS Sprague-Dawley (SD) rats received an intravitreal injection of HGF in the right eye. The left eye was injected with vehicle as a control. Two days after the intravitreal injections, rats were administered 40 mg/kg of sodium iodate (NaIO3) intravenously. Scotopic ERGs were elicited by different stimulus intensities with a maximum luminance of 0.84 log cds/m2. To evaluate RPE function, the azide response was evoked by intravenous injection of 0.1 mg sodium azide. These electrophysiological measurements were conducted on days 4, 7, 14, and 28 after the NaIO3 injections. After recording ERGs or azide response, animals were sacrificed for quantification of the histological change and immunohistochemical analysis using antibodies against RPE 65. RESULTS The threshold for the scotopic b-wave was significantly lower in HGF-treated eyes than in untreated control eyes (p < 0.005), and maximum b-wave amplitudes (Vbmax) were significantly larger in HGF-treated eyes (p < 0.05) across all experimental time points after NaIO3 injection. Azide response amplitudes were significantly larger in the HGF-treated eyes than in the untreated eyes (p < 0.05). The structure of the outer retina was preserved to a greater degree in the HGF-treated eyes than in the untreated eyes (p < 0.05). Immunohistochemical analysis demonstrated that irregular alignment of the outer nuclear layer was confined to the retinal area that was not stained with RPE 65. CONCLUSIONS Our results indicated that an intravitreal injection of HGF provided significant protection against degeneration of the photoreceptor and RPE induced by systemic administration of NaIO3. This suggests that HGF could be used as a therapeutic agent for degeneration of photoreceptors as well as RPE.
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Affiliation(s)
- Kouji Ohtaka
- Department of Ophthalmology, Iwate Medical University School of Medicine, Iwate, Japan
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Ohzeki T, Machida S, Takahashi T, Ohtaka K, Kurosaka D. The Effect of intravitreal N-methyl-DL-aspartic acid on the electroretinogram in Royal College of surgeons rats. Jpn J Ophthalmol 2007; 51:165-74. [PMID: 17554477 DOI: 10.1007/s10384-007-0420-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2006] [Accepted: 01/19/2007] [Indexed: 12/16/2022]
Abstract
PURPOSE To investigate how the third-order neuronal response contributes to shaping the electroretinogram (ERG) in the Royal College of Surgeons (RCS) rat. METHODS Full-field ERGs were recorded from dystrophic RCS rats (n = 30) at 4, 6, 8, 10, 12, or 14 weeks of age in response to different stimulus intensities (maximum intensity, 0.84 log cd-s/m(2)). N-methyl-DL: -aspartic acid (NMDA, 5 mM) was injected into the vitreous cavity of the right eyes to eliminate the third-order neuronal response. The left eyes received the vehicle and served as controls. The third-order neuronal response was isolated by digitally subtracting waveforms of the NMDA-injected eyes from those of the control eyes. RESULTS The ERG a- and b-waves deteriorated with the age of the rat. The third-order neuronal response was preserved to a greater degree than the b-wave despite progression of photoreceptor degeneration. Intravitreal injection of NMDA attenuated the a-wave and enhanced the b-wave across the stimulus range from low to middle intensities. This tendency became more pronounced with advancing rat age. In aged dystrophic RCS rats this phenomenon was seen even at maximum intensity. The difference between NMDA-injected and vehicle-injected eyes was larger for the threshold than for the maximum amplitude at each examined time point (P < 0.001). Intravitreal injection of NMDA decreased implicit times of the a- and b-waves after the rats reached 8 weeks of age (P < 0.005 for the a-wave). CONCLUSION With advancing photoreceptor degeneration, the third-order neuronal response made a greater contribution to shaping the a- and b-waves in dystrophic RCS rats.
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Affiliation(s)
- Takayuki Ohzeki
- Department of Ophthalmology, Iwate Medical University School of Medicine, Morioka, Iwate, Japan
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