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Nicou CM, Passaglia CL. Effect of Ambient Lighting on Intraocular Pressure Rhythms in Rats. Invest Ophthalmol Vis Sci 2024; 65:16. [PMID: 39115866 PMCID: PMC11314632 DOI: 10.1167/iovs.65.10.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Accepted: 07/21/2024] [Indexed: 08/11/2024] Open
Abstract
Purpose The purpose of this study was to determine the effects of ambient lighting on intraocular pressure (IOP) rhythmicity and variability. Methods IOP was continuously recorded by wireless telemetry from rats under light/dark (LD), dark/light (DL), asymmetric (6L18D and 18D6L), constant dark (DD), and constant light (LL) cycles. In some DD experiments, 1-hour light pulses were presented at varying times. IOP rhythmicity and variability were respectively quantified via cosinor analysis and peak detection algorithms that identified transient and sustained fluctuations. Results Rat IOP peaked at night and troughed during the day with LD amplitude of 8.7 ± 3.4 mm Hg. Rhythmicity persisted in DD and LL with a free-running period of 24.1 ± 0.3 and 25.2 ± 0.4 hours, respectively. Peak-to-trough amplitude was approximately 60% smaller in LL, often disappeared after 1 to 2 weeks as daytime IOP drifted 2.6 ± 1.5 mm Hg higher, and returned to approximately 60% larger in LD. Rhythmicity was similarly impacted but resynchronized to DL over 4 to 6 days. Rhythmicity was unaltered by short photoperiods (6L18D), but the nocturnal IOP elevation was markedly shortened by long photoperiods (18L6D) and temporarily lowered to daytime levels by light pulses during the subjective night. Transient and sustained event rate, amplitude, interval, and energy content were nearly identical in LD, DD, and LL. Conclusions Aqueous humor dynamics of rat eyes are intrinsically configured to set IOP at daytime levels. Circadian clock input modulates these dynamics to elevate IOP at night. Light at night blocks this input, sending IOP back to daytime levels. Effects of abnormal lighting on IOP rhythmicity may contribute to pressure-related ocular neuropathies.
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Affiliation(s)
- Christina M. Nicou
- Medical Engineering Department, University of South Florida, Tampa, Florida, United States
| | - Christopher L. Passaglia
- Medical Engineering Department, University of South Florida, Tampa, Florida, United States
- Ophthalmology Department, University of South Florida, Tampa, Florida, United States
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Lozano DC, Yang YF, Cepurna WO, Smoody BF, Ing E, Morrison JC, Keller KE. Profiling IOP-Responsive Genes in the Trabecular Meshwork and Optic Nerve Head in a Rat Model of Controlled Elevation of Intraocular Pressure. Invest Ophthalmol Vis Sci 2024; 65:41. [PMID: 38809543 PMCID: PMC11146053 DOI: 10.1167/iovs.65.5.41] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 05/09/2024] [Indexed: 05/30/2024] Open
Abstract
Purpose The rat controlled elevation of intraocular pressure (CEI) model allows study of in vivo responses to short-term exposure to defined intraocular pressures (IOP). In this study, we used NanoString technology to investigate in vivo IOP-related gene responses in the trabecular meshwork (TM) and optic nerve head (ONH) simultaneously from the same animals. Methods Male and female rats (N = 35) were subjected to CEI for 8 hours at pressures simulating mean, daytime normotensive rat IOP (CEI-20), or 2.5× IOP (CEI-50). Naïve animals that received no anesthesia or surgical interventions served as controls. Immediately after CEI, TM and ONH tissues were dissected, RNA was isolated, and samples were analyzed with a NanoString panel containing 770 genes. Postprocessing, raw count data were uploaded to ROSALIND for differential gene expression analyses. Results For the TM, 45 IOP-related genes were significant in the CEI-50 versus CEI-20 and CEI-50 versus naïve comparisons, with 15 genes common to both comparisons. Bioinformatics analysis identified Notch and transforming growth factor beta (TGFβ) pathways to be the most up- and downregulated Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, respectively. For ONH, 22 significantly differentially regulated genes were identified in the CEI-50 versus naïve comparison. Pathway analysis identified defense response and immune response as two significantly upregulated biological process pathways. Conclusions This study demonstrated the ability to assay short-term IOP-responsive genes in both TM and ONH tissues simultaneously. In the TM, downregulation of TGFβ pathway genes suggests that TM responses may reduce TGFβ-induced extracellular matrix synthesis. For ONH, the initial response to short-term elevated IOP may be protective.
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Affiliation(s)
- Diana C. Lozano
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Yong-Feng Yang
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - William O. Cepurna
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Barbara F. Smoody
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Eliesa Ing
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - John C. Morrison
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Kate E. Keller
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
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3
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Lozano DC, Yang YF, Cepurna WO, Smoody BF, Ing E, Morrison JC, Keller KE. Profiling IOP-responsive genes in anterior and posterior ocular tissues in the rat CEI glaucoma model. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.11.579818. [PMID: 38370622 PMCID: PMC10871322 DOI: 10.1101/2024.02.11.579818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Purpose The rat Controlled Elevation of Intraocular pressure (CEI) model allows study of in vivo responses to defined intraocular pressures (IOP). In this study, we use Nanostring technology to investigate in vivo IOP-related gene responses in the trabecular meshwork (TM) and optic nerve head (ONH) simultaneously from the same animals. Methods Male and female rats (N=35) were subject to CEI for 8-hours at pressures simulating mean, daytime normotensive rat IOP (CEI-20), or 2.5x IOP (CEI-50). Naïve animals, receiving no anesthesia or surgical interventions, served as controls. Immediately after CEI, TM and ONH tissues were dissected, RNA isolated, and samples were analyzed with a Nanostring panel containing 770 genes. Post-processing, raw count data were uploaded to Rosalind® for differential gene expression analyses. Results For the TM, 45 IOP-related genes were significant in the "CEI-50 vs. CEI-20" and "CEI-50 vs. naïve" comparisons, with 15 genes common to both comparisons. Bioinformatics analysis identified Notch and TGFβ pathways to be the most up- and down-regulated KEGG pathways, respectively. For ONH, 22 significantly regulated genes were identified in the "CEI-50 vs. naïve" comparison. Pathway analysis identified 'defense response' and 'immune response' as two significantly upregulated biological process pathways. Conclusions This study demonstrates the ability to assay IOP-responsive genes in both TM and ONH tissues simultaneously. In the TM, downregulation of TGFβ pathway genes suggest that TM responses may prevent TGFβ-induced extracellular matrix synthesis. For ONH, the initial response to elevated IOP may be protective, with astrocytes playing a key role in these gene responses.
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Nicou CM, Passaglia CL. Characterization of intraocular pressure variability in conscious rats. Exp Eye Res 2024; 239:109757. [PMID: 38123009 PMCID: PMC10922224 DOI: 10.1016/j.exer.2023.109757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/10/2023] [Accepted: 12/15/2023] [Indexed: 12/23/2023]
Abstract
Elevation of mean intraocular pressure (IOP) has long been recognized as a leading risk factor for glaucoma. Less is known about the possible contribution of moment-to-moment variations in IOP to disease development and progression due to limitations of tonometry, the prevailing method of IOP measurement. Tonometry provides good estimates of mean IOP but not IOP variance. The aim of this study was to quantitatively characterize IOP variability via round-the-clock IOP telemetry in conscious unrestrained rats. The anterior chamber of one eye was implanted with a microcannula connected to a wireless backpack telemetry system, and IOP data were collected every 4 s for one week. The cannula was then repositioned under the conjunctiva, and control data were collected for an additional week. IOP statistics were computed in 30-min intervals over a 24-h period and averaged across days. All animals exhibited a diurnal variation in mean IOP, while deviations about the mean were independent of time of day. Correlation analysis of the deviations revealed transient and sustained components, which were respectively extracted from IOP records using an event detection algorithm. The amplitude and interval distributions of transient and sustained events were characterized, and their energy content was estimated based on outflow tissue resistance of rat eyes. Transient IOP events occurred ∼231 times per day and were typically ≤5 mmHg in amplitude and 2-8 min in duration, while sustained IOP events occurred ∼16 times per day and were typically ≤5 mmHg in amplitude and 20-60 min in duration. Both persisted but were greatly reduced in control recordings, implying minor contamination of IOP data by motion-induced telemetry noise. Sustained events were also often synchronous across implanted animals, indicating that they were driven by autonomic startle and stress responses or other physiological processes activated by sensory signals in the animal housing environment. Not surprisingly, the total daily fluidic energy applied to resistive outflow pathways was determined primarily by basal IOP level. Nevertheless, transient and sustained fluctuations collectively contributed 6% and diurnal fluctuations contributed 9% to daily IOP energy. It is therefore important to consider the cumulative impact of biomechanical stress that IOP fluctuations apply over time to ocular tissues.
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Affiliation(s)
- Christina M Nicou
- Medical Engineering Department, University of South Florida, Tampa, FL, 33620, USA
| | - Christopher L Passaglia
- Medical Engineering Department, University of South Florida, Tampa, FL, 33620, USA; Ophthalmology Department, University of South Florida, Tampa, FL, 33620, USA.
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Privalov E, Zenkel M, Schloetzer-Schrehardt U, Kuerten S, Bergua A, Hohberger B. Pressure-Dependent Elevation of Vasoactive Intestinal Peptide Level in Chicken Choroid. BIOLOGY 2023; 12:biology12040495. [PMID: 37106696 PMCID: PMC10136289 DOI: 10.3390/biology12040495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 03/13/2023] [Accepted: 03/18/2023] [Indexed: 04/29/2023]
Abstract
PURPOSE Autonomic control is important in maintaining ocular integrity. As recent data suggested that intrinsic choroidal neurons (ICN), an intrinsic choroidal autonomic control, may regulate choroidal thickening via release of the vasodilative vasoactive intestinal peptide (VIP), it was the aim of the study to investigate the level of choroidal VIP (VIPchor) in the presence of an increased atmospheric pressure in a chicken model. METHODS Chicken choroidal whole mounts were exposed to ambient pressure (n = 20) and 40 mm Hg (n = 20) in a PC-controlled, open chamber system for 24 and 72 h, respectively. The VIP concentration was analyzed by ELISA, and the total protein concentration was measured by the BCA assay. Statistical analysis was done using an unpaired two-tailed t-test. RESULTS The pressurization systems enabled choroidal whole mount pressurization (40 mm Hg) with humidifying, pressure, temperature, and gas exchange. Overall, the VIPchor level concentration was significantly increased at 40 mmHg compared to the ambient pressure (30.09 ± 7.18 pg vs. 20.69 ± 3.24 pg; p < 0.0001). Subgroup analysis yielded a significantly increased VIPchor level at 40 mmHg compared to the ambient pressure after 24 h (28.42 ± 6.03 pg vs. 20.76 ± 4.06 pg; p = 0.005) and 72 h (31.77 ± 7.82 pg vs. 20.61 ± 2.12 pg; p = 0.002), respectively. The VIPchor elevation at 40 mm Hg ranged between 1.37- (24 h) and 1.54-fold (72 h) compared to the ambient pressure. No difference was observed between the VIPchor level at 24 h and 72 h (p > 0.05). CONCLUSIONS The increase of the total choroidal VIP level, representing the intracellular VIP content, in the presence of an increased ambient pressure argues for a retention of VIP within the neurons, decreasing both vasodilatation and, consequently, choroid thickness. This finding might be a passive or even active function of ICN in the regulation of choroidal thickness, ocular integrity and IOP.
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Affiliation(s)
- Evgeny Privalov
- Department of Ophthalmology, Universität of Erlangen-Nürnberg, Friedrich-Alexander-University-Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Matthias Zenkel
- Department of Ophthalmology, Universität of Erlangen-Nürnberg, Friedrich-Alexander-University-Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Ursula Schloetzer-Schrehardt
- Department of Ophthalmology, Universität of Erlangen-Nürnberg, Friedrich-Alexander-University-Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Stefanie Kuerten
- Institute of Neuroanatomy, Medical Faculty, University of Bonn, 53115 Bonn, Germany
| | - Antonio Bergua
- Department of Ophthalmology, Universität of Erlangen-Nürnberg, Friedrich-Alexander-University-Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Bettina Hohberger
- Department of Ophthalmology, Universität of Erlangen-Nürnberg, Friedrich-Alexander-University-Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
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Armin A, Arfaee F, Ozmaie S, Asghari A. The evaluation of the effect of tafluprost on the intraocular pressure of healthy male guinea pigs under different light-and-darkness regimes. Vet Med Sci 2023; 9:1172-1178. [PMID: 36757117 DOI: 10.1002/vms3.1082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
BACKGROUND Ocular hypertension is one of the most underdiagnosed ocular abnormalities among guinea pigs around the world. OBJECTIVES The current study investigates the effect of 0.0015% preservative-free tafluprost ophthalmic solution (Zioptan) on the intraocular pressure of 16 healthy male guinea pigs (Cavia porcellus) under different light/darkness regimes. METHODS All guinea pigs received a single drop of tafluprost at 5:30 in the right eye, whereas the contralateral eyes served as control to receive a placebo. Then, the animals were randomly divided into two groups; group A was exposed to light, whereas group B was placed in darkness from 5:30 to 18:00. Rebound tonometry (TonoVet) was instrumented to measure IOP values at 5:30 (baseline), 6:00, 7:00, 8:00, 9:00 and then every 3 h until 18:00. RESULTS The maximum IOP reduction associated with tafluprost was observed at 6:00 by -1.4 ± 1.1 mmHg (p-value = 0.026) and -2.5 ± 1.2 mmHg (p-value = 0.011) in group A and B, respectively (repeated measure ANOVA test). There was a significant difference between the mean right and left eye IOP values in both groups at 5:30, 6:00, 7:00 and 8:00 (p-value <0.05), which was greater in amount in group B compared to group A due to the effect of darkness on IOP reduction. CONCLUSIONS It is suggested that the variations of IOP in different light/dark conditions be taken into consideration when applying ocular hypotensive agents on guinea pigs' eyes.
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Affiliation(s)
- Arghavan Armin
- Department of Clinical Sciences, Faculty of Specialized Veterinary Sciences, The Science and Research Branch of Islamic Azad University, Tehran, Iran
| | - Farnoosh Arfaee
- Department of Clinical Sciences, Faculty of Specialized Veterinary Sciences, The Science and Research Branch of Islamic Azad University, Tehran, Iran
| | - Saeed Ozmaie
- Department of Clinical Sciences, Faculty of Specialized Veterinary Sciences, The Science and Research Branch of Islamic Azad University, Tehran, Iran
| | - Ahmad Asghari
- Department of Clinical Sciences, Faculty of Specialized Veterinary Sciences, The Science and Research Branch of Islamic Azad University, Tehran, Iran
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7
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Silva B, Gonçalves LM, São Braz B, Delgado E. Topical ocular delivery of nanoparticles with epoetin beta in Wistar Hannover rats. Sci Rep 2023; 13:1559. [PMID: 36707615 PMCID: PMC9883504 DOI: 10.1038/s41598-023-28845-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 01/25/2023] [Indexed: 01/29/2023] Open
Abstract
Topical instillation of drugs targeting the posterior ocular segment is an expanding area of research. Chitosan and hyaluronic acid have remarkable mucoadhesive properties and potentially enhance pre-corneal retention time after topical instillation. Bearing this in mind, we explored the possibility of delivering epoetin beta (EPOβ) to the posterior segment of the eye in a chitosan-hyaluronic acid (CS/HA-EPOβ) nanoparticulate system using the topical route of administration. Complete ophthalmological examinations, electroretinography and microhematocrit evaluations were performed in Wistar Hannover (WH) rats, before and after topical administration of nanoparticles. The right eye received CS/HA-EPOβ and the left eye received only empty nanocarriers (control). Animals were split into 6 groups and at designated timepoints, all animals from each group (n = 3) were euthanized and both eyes enucleated. Retinal morphology and EPOβ ocular distribution were assessed, respectively, through hematoxylin and eosin (HE) and immunofluorescence staining. After topical administration, no adverse ocular signs were noted and no significant changes either in microhematocrits nor in electroretinographies were detected. During the study, intraocular pressure (IOP) was always kept within physiological range bilaterally. No histological changes were detected in any of the ocular globes. Immunofluorescence enabled the identification of EPOβ in the retina 12 h after the administration, its presence still being detectable at day 21. In conclusion, CS/HA nanoparticles could efficiently deliver EPOβ to the retina of WH rats after topical instillation, being considered biologically safe. Topical administration of this nanoformulation could be a valuable tool for retinal neuroprotection, decreasing risks associated with more invasive routes of administration, being cost effective and also increasing long-term patients' compliance.
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Affiliation(s)
- Beatriz Silva
- CIISA-Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477, Lisbon, Portugal.,Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1300-477, Lisbon, Portugal.,Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003, Lisbon, Portugal
| | - Lídia M Gonçalves
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003, Lisbon, Portugal
| | - Berta São Braz
- CIISA-Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477, Lisbon, Portugal. .,Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1300-477, Lisbon, Portugal.
| | - Esmeralda Delgado
- CIISA-Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477, Lisbon, Portugal.,Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1300-477, Lisbon, Portugal
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8
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Mohamed Y, Passaglia CL. A portable feedback-controlled pump for monitoring eye outflow facility in conscious rats. PLoS One 2023; 18:e0280332. [PMID: 36630474 PMCID: PMC9833506 DOI: 10.1371/journal.pone.0280332] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 12/27/2022] [Indexed: 01/12/2023] Open
Abstract
Intraocular pressure (IOP) is heavily influenced by the resistance of trabecular outflow pathways through which most of the aqueous humor produced by the eye continuously drains. The standard method of quantifying outflow resistance and other aspects of ocular fluid dynamics is eye cannulation, which allows for direct measurement and manipulation of IOP and flow in animal models. Since the method is invasive, indirect techniques that are slower and less accurate must be used for chronological studies. A novel technology is introduced that can autonomously measure outflow facility in conscious rats multiple times a day. A smart portable micropump infuses fluid into the eye through a permanently-implanted cannula and dynamically adjusts flow rate using a unique proportional feedback algorithm that sets IOP to a target level, even though IOP fluctuates erratically in awake free-moving animals. Pressure-flow data collected by the system from anesthetized rats were validated against intraocular recordings with commercial pressure and flow sensors. System and sensor estimates of outflow facility were indistinguishable, averaging 23 ± 3 nl·min-1·mmHg-1 across animals (n = 11). Pressure-flow data were then collected round-the-clock for several days from conscious rats, while outflow facility was measured every few hours. A significant diurnal facility rhythm was observed in every animal (n = 4), with mean daytime level of 22 ± 10 nl·min-1·mmHg-1 and mean nighttime level of 15 ± 7 nl·min-1·mmHg-1. The rhythm correlated with diurnal changes in IOP and likely contributed prominently to those changes based on the day-night swing in facility magnitude. Hence, the portable smart pump offers a unique tool for repeated long-term monitoring of outflow facility and other possible parameters of ocular health. It could also be useful in animal glaucoma studies for reversibly inducing acute or chronic ocular hypertension without explicitly damaging trabecular outflow pathways.
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Affiliation(s)
- Youssef Mohamed
- Department of Medical Engineering, University of South Florida, Tampa, FL, United States of America
| | - Christopher L. Passaglia
- Department of Medical Engineering, University of South Florida, Tampa, FL, United States of America
- Department of Ophthalmology, University of South Florida, Tampa, FL, United States of America
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9
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Bertens CJF, van Mechelen RJS, Berendschot TTJM, Gijs M, Wolters JEJ, Gorgels TGMF, Nuijts RMMA, Beckers HJM. Repeatability, reproducibility, and agreement of three tonometers for measuring intraocular pressure in rabbits. Sci Rep 2021; 11:19217. [PMID: 34584185 PMCID: PMC8478901 DOI: 10.1038/s41598-021-98762-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/14/2021] [Indexed: 12/04/2022] Open
Abstract
The aim of this study was to evaluate repeatability, reproducibility, and agreement of three commonly used tonometers in animal research (TonoLab, TonoVet, and TonoPEN AVIA) in a cohort of 24 rabbits. Additionally, the impact of sedation on IOP was investigated in 21 New Zealand White rabbits with the TonoVet tonometer. Repeatability was determined using the coefficient of variation (CoV) for two observers. For the TonoLab (6.55%) and TonoVet (6.38%) the CoV was lower than for the TonoPEN AVIA (10.88%). The reproducibility was highest for the TonoVet (0.2 ± 3.3 mmHg), followed by the TonoLab (0 ± 12.89 mmHg) and lowest for the TonoPEN AVIA (− 1.48 ± 10.3 mmHg). The TonoLab and TonoVet showed the highest agreement (r = 0.85, R2 = 0.73). After sedation, a significant IOP reduction (often > 25%) was observed. Our results show that among the three tonometers tested, the TonoVet tonometer is best for use in rabbits while the TonoLab should be avoided. The impact of sedation on IOP was substantial and should be taken into account during experimentation.
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Affiliation(s)
- Christian J F Bertens
- Department of Ophthalmology, University Eye Clinic Maastricht, School for Mental Health and Neuroscience (MHeNs), Maastricht University Medical Center+ (MUMC+), P. Debyelaan 25, PO Box 5800, 6229 HX, Maastricht, The Netherlands. .,Chemelot Institute for Science and Technology (InSciTe), Gaetano Martinolaan 63-65, 6229 GS, Maastricht, The Netherlands.
| | - Ralph J S van Mechelen
- Department of Ophthalmology, University Eye Clinic Maastricht, School for Mental Health and Neuroscience (MHeNs), Maastricht University Medical Center+ (MUMC+), P. Debyelaan 25, PO Box 5800, 6229 HX, Maastricht, The Netherlands.,Chemelot Institute for Science and Technology (InSciTe), Gaetano Martinolaan 63-65, 6229 GS, Maastricht, The Netherlands
| | - Tos T J M Berendschot
- Department of Ophthalmology, University Eye Clinic Maastricht, School for Mental Health and Neuroscience (MHeNs), Maastricht University Medical Center+ (MUMC+), P. Debyelaan 25, PO Box 5800, 6229 HX, Maastricht, The Netherlands
| | - Marlies Gijs
- Department of Ophthalmology, University Eye Clinic Maastricht, School for Mental Health and Neuroscience (MHeNs), Maastricht University Medical Center+ (MUMC+), P. Debyelaan 25, PO Box 5800, 6229 HX, Maastricht, The Netherlands.,Chemelot Institute for Science and Technology (InSciTe), Gaetano Martinolaan 63-65, 6229 GS, Maastricht, The Netherlands
| | - Jarno E J Wolters
- Department of Ophthalmology, University Eye Clinic Maastricht, School for Mental Health and Neuroscience (MHeNs), Maastricht University Medical Center+ (MUMC+), P. Debyelaan 25, PO Box 5800, 6229 HX, Maastricht, The Netherlands.,Chemelot Institute for Science and Technology (InSciTe), Gaetano Martinolaan 63-65, 6229 GS, Maastricht, The Netherlands
| | - Theo G M F Gorgels
- Department of Ophthalmology, University Eye Clinic Maastricht, School for Mental Health and Neuroscience (MHeNs), Maastricht University Medical Center+ (MUMC+), P. Debyelaan 25, PO Box 5800, 6229 HX, Maastricht, The Netherlands.,Chemelot Institute for Science and Technology (InSciTe), Gaetano Martinolaan 63-65, 6229 GS, Maastricht, The Netherlands
| | - Rudy M M A Nuijts
- Department of Ophthalmology, University Eye Clinic Maastricht, School for Mental Health and Neuroscience (MHeNs), Maastricht University Medical Center+ (MUMC+), P. Debyelaan 25, PO Box 5800, 6229 HX, Maastricht, The Netherlands.,Chemelot Institute for Science and Technology (InSciTe), Gaetano Martinolaan 63-65, 6229 GS, Maastricht, The Netherlands
| | - Henny J M Beckers
- Department of Ophthalmology, University Eye Clinic Maastricht, School for Mental Health and Neuroscience (MHeNs), Maastricht University Medical Center+ (MUMC+), P. Debyelaan 25, PO Box 5800, 6229 HX, Maastricht, The Netherlands.,Chemelot Institute for Science and Technology (InSciTe), Gaetano Martinolaan 63-65, 6229 GS, Maastricht, The Netherlands
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10
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Nicou CM, Pillai A, Passaglia CL. Effects of acute stress, general anesthetics, tonometry, and temperature on intraocular pressure in rats. Exp Eye Res 2021; 210:108727. [PMID: 34390732 DOI: 10.1016/j.exer.2021.108727] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/30/2021] [Accepted: 08/10/2021] [Indexed: 10/20/2022]
Abstract
Intraocular pressure (IOP) is important for eye health as abnormal levels can led to ocular tissue damage. IOP is typically estimated by tonometry, which only provides snapshots of pressure history. Tonometry also requires subject cooperation and corneal contact that may influence IOP readings. The aim of this research was to investigate IOP dynamics of conscious animals in response to stressors, common anesthetics, tonometry, and temperature manipulations. An eye of male Brown-Norway rats was implanted with a fluid-filled cannula connected to a wireless telemetry system that records IOP continuously. Stress effects were examined by restricting animal movements. Anesthetic effects were examined by varying isoflurane concentration or injecting a bolus of ketamine. Tonometry effects were examined using applanation and rebound tonometers. Temperature effects were examined by exposing anesthetized and conscious animals to warm or cool surfaces. Telemetry recordings revealed that IOP fluctuates spontaneously by several mmHg, even in idle and anesthetized animals. Environmental disturbances also caused transient IOP fluctuations that were synchronous in recorded animals and could last over a half hour. Animal immobilization produced a rapid sustained elevation of IOP that was blocked by anesthetics, whereas little-to-no IOP change was detected in isoflurane- or ketamine-anesthetized animals if body temperature (BT) was maintained. IOP and BT decreased precipitously when heat support was not provided and were highly correlated during surface temperature manipulations. Surface temperature had no impact on IOP of conscious animals. IOP increased slightly during applanation tonometry but not rebound tonometry. The results show that IOP is dynamically modulated by internal and external factors that can activate rapidly and last long beyond the initiating event. Wireless telemetry indicates that animal interaction induces startle and stress responses that raise IOP. Anesthesia blocks these responses, which allows for better tonometry estimates of resting IOP provided that BT is controlled.
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Affiliation(s)
- Christina M Nicou
- Medical Engineering Department, University of South Florida, Tampa, FL, 33620, USA
| | - Aditi Pillai
- Medical Engineering Department, University of South Florida, Tampa, FL, 33620, USA
| | - Christopher L Passaglia
- Medical Engineering Department, University of South Florida, Tampa, FL, 33620, USA; Ophthalmology Department, University of South Florida, Tampa, FL, 33620, USA.
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11
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Tsuchiya S, Higashide T, Hatake S, Sugiyama K. Effect of inhalation anesthesia with isoflurane on circadian rhythm of murine intraocular pressure. Exp Eye Res 2020; 203:108420. [PMID: 33359512 DOI: 10.1016/j.exer.2020.108420] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/24/2020] [Accepted: 12/21/2020] [Indexed: 01/01/2023]
Abstract
PURPOSE For research on circadian intraocular pressure (IOP), rebound tonometers are widely used with or without general anesthesia as a non-invasive approach to obtain IOP values. However, whether general anesthesia such as inhalation anesthesia with isoflurane affects the circadian rhythm of IOP and in turn IOP measurements is currently unclear. As such, data reporting IOP values obtained under general anesthesia should be interpreted with caution. The purpose of this study was to evaluate how general anesthesia with isoflurane inhalation affects the circadian rhythm of IOP. METHODS C57Bl/6J strain mice maintained using a 12h:12h light/dark cycle (lights on and off at ZT0 and ZT12, respectively) were used. IOPs were measured using a rebound tonometer (Icare TonoLab) before and 3, 5, 10, 15, and 30 min after initiating anesthesia in both light and dark phases (ZT 2-6 and ZT 14-18, respectively). Awake IOPs and IOPs at 3 and 5 min after anesthesia initiation were also obtained at ZT5, 8, 11, 14, 17, and 20 to assess IOP diurnal curves under gas anesthesia. RESULTS IOP values gradually decreased after anesthesia initiation in both light and dark phases (P < 0.001) and there was no interaction between light/dark phase and anesthesia time (P = 0.88). There was a slight, but not significant, reduction in IOP 3 min after initiating anesthesia (P = 0.23), and significant decreases in IOP occurred at subsequent timepoints (P ≤ 0.001). Both awake and anesthetized mice showed a robust IOP rhythm that reached a peak and trough in the dark and light phase, respectively. Awake IOP levels did not significantly differ from those for anesthetized mice at 3 min after anesthesia initiation at all time points (P ≥ 0.07). CONCLUSIONS Both awake and anesthetized mice demonstrated a robust circadian rhythm for IOP. Murine IOP showed similar gradual decreases under inhalation anesthesia with isoflurane in both the light and dark phases. IOPs measured using a rebound tonometer within 3 min of initiating isoflurane anesthesia were comparable to awake IOPs, and thus may be useful to monitor the circadian rhythm of IOP in mice.
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Affiliation(s)
- Shunsuke Tsuchiya
- Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Tomomi Higashide
- Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan.
| | - Sachiyo Hatake
- Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Kazuhisa Sugiyama
- Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
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12
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Feola AJ, Sherwood JM, Pardue MT, Overby DR, Ethier CR. Age and Menopause Effects on Ocular Compliance and Aqueous Outflow. Invest Ophthalmol Vis Sci 2020; 61:16. [PMID: 32407519 PMCID: PMC7405619 DOI: 10.1167/iovs.61.5.16] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Glaucoma is the second leading cause of blindness worldwide. Recent work suggests that estrogen and the timing of menopause play a role in modulating the risk of developing glaucoma. Menopause is known to cause modest changes in intraocular pressure; yet, whether this change is mediated through the outflow pathway remains unknown. Menopause also affects tissue biomechanical properties throughout the body; however, the impact of menopause on ocular biomechanical properties is not well characterized. Methods Here, we simultaneously assessed the impact of menopause on aqueous outflow facility and ocular compliance, as a measure of corneoscleral shell biomechanics. We used young (3-4 months old) and middle-aged (9-10 months old) Brown Norway rats. Menopause was induced by ovariectomy (OVX), and control animals underwent sham surgery, resulting in the following groups: young sham (n = 5), young OVX (n = 6), middle-aged sham (n = 5), and middle-aged OVX (n = 5). Eight weeks postoperatively, we measured outflow facility and ocular compliance. Results Menopause resulted in a 34% decrease in outflow facility and a 19% increase in ocular compliance (P = 0.011) in OVX animals compared with sham controls (P = 0.019). Conclusions These observations reveal that menopause affects several key physiological factors known to be associated with glaucoma, suggesting that menopause may contribute to an increased risk of glaucoma in women.
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13
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Luo LJ, Nguyen DD, Lai JY. Benzoic acid derivative-modified chitosan-g-poly(N-isopropylacrylamide): Methoxylation effects and pharmacological treatments of Glaucoma-related neurodegeneration. J Control Release 2020; 317:246-258. [DOI: 10.1016/j.jconrel.2019.11.038] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 11/11/2019] [Accepted: 11/28/2019] [Indexed: 01/29/2023]
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14
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Gillmann K, Bravetti GE, Niegowski LJ, Mansouri K. Using sensors to estimate intraocular pressure: a review of intraocular pressure telemetry in clinical practice. EXPERT REVIEW OF OPHTHALMOLOGY 2019. [DOI: 10.1080/17469899.2019.1681264] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Kevin Gillmann
- Glaucoma Research Center, Montchoisi Clinic, Swiss Visio, Lausanne, Switzerland
| | | | | | - Kaweh Mansouri
- Glaucoma Research Center, Montchoisi Clinic, Swiss Visio, Lausanne, Switzerland
- Department of Ophthalmology, University of Colorado School of Medicine, Denver, CO, USA
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15
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Ziółkowska N, Ziółkowski H, Magda J, Bućko M, Kaczorek-Łukowska E, Lewczuk B. Diurnal and circadian variations in intraocular pressure in goats exposed to different lighting conditions. Chronobiol Int 2019; 36:1638-1645. [PMID: 31495221 DOI: 10.1080/07420528.2019.1660360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The effect of constant light and constant darkness on intraocular pressure (IOP) in goats has not been investigated. We hypothesized that IOP variations would differ between goats kept under a cycle of 12 hours of light and 12 hours of darkness (LD), constant darkness (DD), and constant light (LL). To test this hypothesis, goats were exposed to these conditions for five days (LD, 30 goats; DD, 10 goats; LL, 10 goats). IOP was measured by applanation tonometry at 9 a.m. (beginning of photophase in LD) and 9 p.m. (beginning of scotophase in LD) on the fourth and fifth days of exposure. We found that changes in mean IOP from 9 a.m. to 9 p.m. differed significantly between groups (χ2(2) = 23.04, p < .0001). Most goats in LD showed a regular pattern of higher IOP in the morning and lower IOP in the evening, whereas those in DD and LL did not follow this pattern. In LD conditions, mean IOP was 2.4 mm Hg lower at 9 p.m. than at 9 a.m. (95% confidence interval for the difference (CI): -2.8 to -1.9 mm Hg, p < .0001). In DD conditions, mean IOP did not differ between 9 p.m. and 9 a.m. (CI: -0.9 to 0.8 mm Hg, p = .90). In LL conditions, it was 0.6 mm Hg lower at 9 p.m. (CI: -1.5 to 0.2 mm Hg, p = .12). Our results indicate that IOP in goats kept in LD is higher in the morning than in the evening, and that IOP variations are reduced in goats kept in DD and LL. These results suggest that exposure to alternating periods of light and darkness is important for maintaining rhythmic variations in IOP in this species.
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Affiliation(s)
- Natalia Ziółkowska
- Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland
| | - Hubert Ziółkowski
- Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland
| | - Jagoda Magda
- Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland
| | - Monika Bućko
- Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland
| | - Edyta Kaczorek-Łukowska
- Department of Microbiology and Clinical Immunology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland
| | - Bogdan Lewczuk
- Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland
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16
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A Chronic Ocular-Hypertensive Rat Model induced by Injection of the Sclerosant Agent Polidocanol in the Aqueous Humor Outflow Pathway. Int J Mol Sci 2019; 20:ijms20133209. [PMID: 31261943 PMCID: PMC6650807 DOI: 10.3390/ijms20133209] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 06/26/2019] [Accepted: 06/27/2019] [Indexed: 11/16/2022] Open
Abstract
Background: To induce a moderate chronic ocular hypertension (OHT) by injecting polidocanol, a foamed sclerosant drug, in the aqueous humor outflow pathway. Methods: Intraocular pressure (IOP) was monitored for up to 6 months. Pattern and full-field electroretinogram (PERG and ERG) were recorded and retinal ganglion cells (RGC) and retinal nerve fiber layer (RNFL) thickness were assessed in vivo with optical coherence tomography (OCT) and ex vivo using Brn3a immunohistochemistry. Results: In the first 3 weeks post-injection, a significant IOP elevation was observed in the treated eyes (18.47 ± 3.36 mmHg) when compared with the control fellow eyes (12.52 ± 2.84 mmHg) (p < 0.05). At 8 weeks, 65% (11/17) of intervention eyes had developed an IOP increase >25% over the baseline. PERG responses were seen to be significantly reduced in the hypertensive eyes (2.25 ± 0.24 µV) compared to control eyes (1.44 ± 0.19 µV) (p < 0.01) at week 3, whereas the ERG components (photoreceptor a-wave and bipolar cell b-wave) remained unaltered. By week 24, RNFL thinning and cell loss in the ganglion cell layer was first detected (2/13, 15.3%) as assessed by OCT and light microscopy. Conclusions: This novel OHT rat model, with moderate levels of chronically elevated IOP, and abnormal PERG shows selective functional impairment of RGC.
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17
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Felder-Schmittbuhl MP, Buhr ED, Dkhissi-Benyahya O, Hicks D, Peirson SN, Ribelayga CP, Sandu C, Spessert R, Tosini G. Ocular Clocks: Adapting Mechanisms for Eye Functions and Health. Invest Ophthalmol Vis Sci 2019; 59:4856-4870. [PMID: 30347082 PMCID: PMC6181243 DOI: 10.1167/iovs.18-24957] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Vision is a highly rhythmic function adapted to the extensive changes in light intensity occurring over the 24-hour day. This adaptation relies on rhythms in cellular and molecular processes, which are orchestrated by a network of circadian clocks located within the retina and in the eye, synchronized to the day/night cycle and which, together, fine-tune detection and processing of light information over the 24-hour period and ensure retinal homeostasis. Systematic or high throughput studies revealed a series of genes rhythmically expressed in the retina, pointing at specific functions or pathways under circadian control. Conversely, knockout studies demonstrated that the circadian clock regulates retinal processing of light information. In addition, recent data revealed that it also plays a role in development as well as in aging of the retina. Regarding synchronization by the light/dark cycle, the retina displays the unique property of bringing together light sensitivity, clock machinery, and a wide range of rhythmic outputs. Melatonin and dopamine play a particular role in this system, being both outputs and inputs for clocks. The retinal cellular complexity suggests that mechanisms of regulation by light are diverse and intricate. In the context of the whole eye, the retina looks like a major determinant of phase resetting for other tissues such as the retinal pigmented epithelium or cornea. Understanding the pathways linking the cell-specific molecular machineries to their cognate outputs will be one of the major challenges for the future.
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Affiliation(s)
- Marie-Paule Felder-Schmittbuhl
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives (UPR 3212), Strasbourg, France
| | - Ethan D Buhr
- Department of Ophthalmology, University of Washington Medical School, Seattle, Washington, United States
| | - Ouria Dkhissi-Benyahya
- Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, Bron, France
| | - David Hicks
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives (UPR 3212), Strasbourg, France
| | - Stuart N Peirson
- Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Christophe P Ribelayga
- Ruiz Department of Ophthalmology and Visual Science, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, United States
| | - Cristina Sandu
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives (UPR 3212), Strasbourg, France
| | - Rainer Spessert
- Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Gianluca Tosini
- Neuroscience Institute and Department of Pharmacology & Toxicology, Morehouse School of Medicine, Atlanta, Georgia, United States
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18
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Troilo D, Smith EL, Nickla DL, Ashby R, Tkatchenko AV, Ostrin LA, Gawne TJ, Pardue MT, Summers JA, Kee CS, Schroedl F, Wahl S, Jones L. IMI - Report on Experimental Models of Emmetropization and Myopia. Invest Ophthalmol Vis Sci 2019; 60:M31-M88. [PMID: 30817827 PMCID: PMC6738517 DOI: 10.1167/iovs.18-25967] [Citation(s) in RCA: 231] [Impact Index Per Article: 46.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Accepted: 10/20/2018] [Indexed: 11/24/2022] Open
Abstract
The results of many studies in a variety of species have significantly advanced our understanding of the role of visual experience and the mechanisms of postnatal eye growth, and the development of myopia. This paper surveys and reviews the major contributions that experimental studies using animal models have made to our thinking about emmetropization and development of myopia. These studies established important concepts informing our knowledge of the visual regulation of eye growth and refractive development and have transformed treatment strategies for myopia. Several major findings have come from studies of experimental animal models. These include the eye's ability to detect the sign of retinal defocus and undergo compensatory growth, the local retinal control of eye growth, regulatory changes in choroidal thickness, and the identification of components in the biochemistry of eye growth leading to the characterization of signal cascades regulating eye growth and refractive state. Several of these findings provided the proofs of concepts that form the scientific basis of new and effective clinical treatments for controlling myopia progression in humans. Experimental animal models continue to provide new insights into the cellular and molecular mechanisms of eye growth control, including the identification of potential new targets for drug development and future treatments needed to stem the increasing prevalence of myopia and the vision-threatening conditions associated with this disease.
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Affiliation(s)
- David Troilo
- SUNY College of Optometry, State University of New York, New York, New York, United States
| | - Earl L. Smith
- College of Optometry, University of Houston, Houston, Texas, United States
| | - Debora L. Nickla
- Biomedical Sciences and Disease, New England College of Optometry, Boston, Massachusetts, United States
| | - Regan Ashby
- Health Research Institute, University of Canberra, Canberra, Australia
| | - Andrei V. Tkatchenko
- Department of Ophthalmology, Department of Pathology and Cell Biology, Columbia University, New York, New York, United States
| | - Lisa A. Ostrin
- College of Optometry, University of Houston, Houston, Texas, United States
| | - Timothy J. Gawne
- School of Optometry, University of Alabama Birmingham, Birmingham, Alabama, United States
| | - Machelle T. Pardue
- Biomedical Engineering, Georgia Tech College of Engineering, Atlanta, Georgia, United States31
| | - Jody A. Summers
- College of Medicine, University of Oklahoma, Oklahoma City, Oklahoma, United States
| | - Chea-su Kee
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, SAR, China
| | - Falk Schroedl
- Departments of Ophthalmology and Anatomy, Paracelsus Medical University, Salzburg, Austria
| | - Siegfried Wahl
- Institute for Ophthalmic Research, University of Tuebingen, Zeiss Vision Science Laboratory, Tuebingen, Germany
| | - Lyndon Jones
- CORE, School of Optometry and Vision Science, University of Waterloo, Ontario, Canada
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19
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Chakraborty R, Ostrin LA, Nickla DL, Iuvone PM, Pardue MT, Stone RA. Circadian rhythms, refractive development, and myopia. Ophthalmic Physiol Opt 2018; 38:217-245. [PMID: 29691928 PMCID: PMC6038122 DOI: 10.1111/opo.12453] [Citation(s) in RCA: 121] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/11/2018] [Indexed: 12/14/2022]
Abstract
PURPOSE Despite extensive research, mechanisms regulating postnatal eye growth and those responsible for ametropias are poorly understood. With the marked recent increases in myopia prevalence, robust and biologically-based clinical therapies to normalize refractive development in childhood are needed. Here, we review classic and contemporary literature about how circadian biology might provide clues to develop a framework to improve the understanding of myopia etiology, and possibly lead to rational approaches to ameliorate refractive errors developing in children. RECENT FINDINGS Increasing evidence implicates diurnal and circadian rhythms in eye growth and refractive error development. In both humans and animals, ocular length and other anatomical and physiological features of the eye undergo diurnal oscillations. Systemically, such rhythms are primarily generated by the 'master clock' in the surpachiasmatic nucleus, which receives input from the intrinsically photosensitive retinal ganglion cells (ipRGCs) through the activation of the photopigment melanopsin. The retina also has an endogenous circadian clock. In laboratory animals developing experimental myopia, oscillations of ocular parameters are perturbed. Retinal signaling is now believed to influence refractive development; dopamine, an important neurotransmitter found in the retina, not only entrains intrinsic retinal rhythms to the light:dark cycle, but it also modulates refractive development. Circadian clocks comprise a transcription/translation feedback control mechanism utilizing so-called clock genes that have now been associated with experimental ametropias. Contemporary clinical research is also reviving ideas first proposed in the nineteenth century that light exposures might impact refraction in children. As a result, properties of ambient lighting are being investigated in refractive development. In other areas of medical science, circadian dysregulation is now thought to impact many non-ocular disorders, likely because the patterns of modern artificial lighting exert adverse physiological effects on circadian pacemakers. How, or if, such modern light exposures and circadian dysregulation contribute to refractive development is not known. SUMMARY The premise of this review is that circadian biology could be a productive area worthy of increased investigation, which might lead to the improved understanding of refractive development and improved therapeutic interventions.
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Affiliation(s)
- Ranjay Chakraborty
- College of Nursing and Health Sciences, Flinders University, Adelaide, Australia
| | | | | | | | - Machelle T. Pardue
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta
- Atlanta VA Center for Visual and Neurocognitive Rehabilitation, Decatur
| | - Richard A. Stone
- University of Pennsylvania School of Medicine, Philadelphia, USA
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20
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Hohberger B, Jessberger C, Hermann F, Zenkel M, Kaser-Eichberger A, Bergua A, Jünemann AG, Schrödl F, Neuhuber W. VIP changes during daytime in chicken intrinsic choroidal neurons. Exp Eye Res 2018; 170:8-12. [DOI: 10.1016/j.exer.2018.01.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 12/06/2017] [Accepted: 01/29/2018] [Indexed: 12/01/2022]
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21
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Patel GC, Liu Y, Millar JC, Clark AF. Glucocorticoid receptor GRβ regulates glucocorticoid-induced ocular hypertension in mice. Sci Rep 2018; 8:862. [PMID: 29339763 PMCID: PMC5770444 DOI: 10.1038/s41598-018-19262-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 12/21/2017] [Indexed: 01/26/2023] Open
Abstract
Prolonged glucocorticoid (GC) therapy can cause GC-induced ocular hypertension (OHT), which if left untreated progresses to iatrogenic glaucoma and permanent vision loss. The alternatively spliced isoform of glucocorticoid receptor GRβ acts as dominant negative regulator of GR activity, and it has been shown that overexpressing GRβ in trabecular meshwork (TM) cells inhibits GC-induced glaucomatous damage in TM cells. The purpose of this study was to use viral vectors to selectively overexpress the GRβ isoform in the TM of mouse eyes treated with GCs, to precisely dissect the role of GRβ in regulating steroid responsiveness. We show that overexpression of GRβ inhibits GC effects on MTM cells in vitro and GC-induced OHT in mouse eyes in vivo. Ad5 mediated GRβ overexpression reduced the GC induction of fibronectin, collagen 1, and myocilin in TM of mouse eyes both in vitro and in vivo. GRβ also reversed DEX-Ac induced IOP elevation, which correlated with increased conventional aqueous humor outflow facility. Thus, GRβ overexpression reduces effects caused by GCs and makes cells more resistant to GC treatment. In conclusion, our current work provides the first evidence of the in vivo physiological role of GRβ in regulating GC-OHT and GC-mediated gene expression in the TM.
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Affiliation(s)
- Gaurang C Patel
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States
| | - Yang Liu
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States
| | - J Cameron Millar
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States
| | - Abbot F Clark
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States.
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22
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Morrison JC, Johnson EC, Cepurna WO. Hypertonic Saline Injection Model of Experimental Glaucoma in Rats. Methods Mol Biol 2018; 1695:11-21. [PMID: 29190014 DOI: 10.1007/978-1-4939-7407-8_2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A reliable method of creating chronic elevation of intraocular pressure (IOP) in rodents is an important tool in reproducing and studying the mechanisms of optic nerve injury that occur in glaucoma. In addition, such a model could provide a valuable method for testing potential neuroprotective treatments. This paper outlines the basic methods for producing obstruction of aqueous humor outflow and IOP elevation by injecting hypertonic saline (a sclerosant) into the aqueous outflow pathway. This is one of several rodent glaucoma models in use today. In this method, a plastic ring is placed around the equator of the eye to restrict injected saline to the limbus. By inserting a small glass microneedle in an aqueous outflow vein in the episclera and injecting hypertonic saline toward the limbus, the saline is forced into Schlemm's canal and across the trabecular meshwork. The resultant inflammation and scarring of the anterior chamber angle occurs gradually, resulting in a rise in IOP after approximately 1 week. This article will describe the equipment necessary for producing this model and the steps of the technique itself.
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Affiliation(s)
- John C Morrison
- Casey Eye Institute, Oregon Health and Science University, 3375 S.W. Terwilliger Blvd, Portland, OR, 97239, USA.
| | - Elaine C Johnson
- Casey Eye Institute, Oregon Health and Science University, 3375 S.W. Terwilliger Blvd, Portland, OR, 97239, USA
| | - William O Cepurna
- Casey Eye Institute, Oregon Health and Science University, 3375 S.W. Terwilliger Blvd, Portland, OR, 97239, USA
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23
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Abstract
Intraocular pressure (IOP) elevation is a critical risk factor for development and progression of glaucoma. As such, measuring IOP in animal models of the disease is important for any research work trying to understand the pathophysiologic mechanisms of glaucoma. Noninvasive IOP measurement in animals uses methods that have been adapted from use on humans. Calibration of the instruments used for the specific animal and even strain used is critically important for allowing meaningful comparisons of results. We describe below the methods used for noninvasive IOP measurement in animals that are relevant to glaucoma research.
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24
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Bello SA, Passaglia CL. A Wireless Pressure Sensor for Continuous Monitoring of Intraocular Pressure in Conscious Animals. Ann Biomed Eng 2017; 45:2592-2604. [PMID: 28812168 PMCID: PMC7034622 DOI: 10.1007/s10439-017-1896-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 08/05/2017] [Indexed: 11/30/2022]
Abstract
An important aspect of eye health in humans and animal models of human diseases is intraocular pressure (IOP). IOP is typically measured by hand with a tonometer, so data are sparse and sporadic and round-the-clock variations are not well characterized. Here we present a novel system for continuous wireless IOP and temperature measurement in small animals. The system consists of a cannula implanted in the anterior chamber of the eye connected to pressure sensing electronics that can be worn by rats or implanted in larger mammals. The system can record IOP with 0.3 mmHg accuracy and negligible drift at a rate of 0.25 Hz for 1-2 months on a regulated battery or indefinitely at rates up to 250 Hz via RF energy harvesting. Chronic recordings from conscious rats showed that IOP follows a diurnal rhythm, averaging 16.5 mmHg during the day and 21.7 mmHg at night, and that the IOP rhythm lags a diurnal rhythm in body temperature by 2.1 h. IOP and body temperature fluctuations were positively correlated from moment-to-moment as well. This technology allows researchers to monitor for the first time the precise IOP history of rat eyes, a popular model for glaucoma studies.
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Affiliation(s)
- Simon A Bello
- Department of Electrical Engineering, University of South Florida, Tampa, FL, 33620, USA
| | - Christopher L Passaglia
- Department of Chemical and Biomedical Engineering, University of South Florida, 4202 E Fowler Ave, Tampa, FL, 33620, USA.
- Department of Ophthalmology, University of South Florida, Tampa, FL, 33620, USA.
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25
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Light entrainment of the murine intraocular pressure circadian rhythm utilizes non-local mechanisms. PLoS One 2017; 12:e0184790. [PMID: 28934261 PMCID: PMC5608236 DOI: 10.1371/journal.pone.0184790] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Accepted: 08/30/2017] [Indexed: 11/26/2022] Open
Abstract
Purpose Intraocular pressure (IOP) is known to have a strong circadian rhythm, yet how light/dark cycles entrain this rhythm is unknown. The purpose of this study was to assess whether, like the retina, the mammalian ciliary body and IOP clocks have an intrinsic ability to entrain to light/dark cycles. Methods Iris-ciliary body complexes were obtained from period2:luciferase (PER2::LUC) mice and cultured to measure bioluminescence rhythmicity. Pairs of the iris-ciliary body complex were exposed to antiphasic 9:15 h light/dark cycle in vitro. After 4 days of exposure to light/dark cycles, bioluminescence was recorded to establish their circadian phases. In addition, pairs of the iris-ciliary body complex co-cultured with the retinas or corneas of wild-type mice were also investigated. The IOP circadian changes of free-running Opn4-/-;rd1/rd1 mice whose behavior was antiphasic to wild-type were measured by a rebound tonometry, and compared with wild-type mice. Opn3, Opn4, and Opn5 mRNA expression in the iris-ciliary body were analyzed using RT-PCR. Results The iris/ciliary body complex expressed Opn3, Opn4, and Opn5 mRNA; however, unlike in retina and cornea, neither the iris-CB complex nor the co-cultured complex was directly entrained by light-dark cycle in vitro. The diurnal IOP change of Opn4-/-;rd1/rd1 mice showed an antiphasic pattern to wild-type mice and their rhythms followed the whole-animal behavioral rhythm. Conclusions Despite expressing mRNA for several non-visual opsins, circadian rhythms of the iris-ciliary body complex of mice do not entrain directly to light-dark cycles ex vivo. Unlike retina, the iris/ciliary body clocks of blind mice remain synchronized to the organismal behavioral rhythm rather than local light-dark cycles. These results suggest that IOP rhythm entrainment is mediated by a systemic rather than local signal in mice.
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Affiliation(s)
- Mohammadali Almasieh
- Departments of Ophthalmology and Neurology, McGill University, Montreal H4A 3S5, Canada
- Maisonneuve-Rosemont Hospital Research Center and Department of Ophthalmology, University of Montreal, Montreal H1T 2M4, Canada
| | - Leonard A. Levin
- Departments of Ophthalmology and Neurology, McGill University, Montreal H4A 3S5, Canada
- Maisonneuve-Rosemont Hospital Research Center and Department of Ophthalmology, University of Montreal, Montreal H1T 2M4, Canada
- Department of Ophthalmology and Visual Science, University of Wisconsin, Madison, Wisconsin 53706
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Bello SA, Malavade S, Passaglia CL. Development of a Smart Pump for Monitoring and Controlling Intraocular Pressure. Ann Biomed Eng 2017; 45:990-1002. [PMID: 27679446 PMCID: PMC5364042 DOI: 10.1007/s10439-016-1735-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Accepted: 09/12/2016] [Indexed: 10/20/2022]
Abstract
Animal models of ocular hypertension are important for glaucoma research but come with experimental costs. Available methods of intraocular pressure (IOP) elevation are not always successful, the amplitude and time course of IOP changes are unpredictable and irreversible, and IOP measurement by tonometry is laborious. Here we present a novel system for monitoring and controlling IOP without these limitations. It consists of a cannula implanted in the anterior chamber of the eye, a pressure sensor that continually measures IOP, and a bidirectional pump driven by control circuitry that can infuse or withdraw fluid to hold IOP at user-desired levels. A portable version was developed for tethered use on rats. We show that rat eyes can be cannulated for months without causing significant anatomical or physiological damage although the animal and its eyes freely move. We show that the system measures IOP with <0.7 mmHg resolution and <0.3 mmHg/month drift and can maintain IOP within a user-specified window of desired levels for any duration necessary. We conclude that the system is ready for cage- or bench-side applications. The results lay the foundation for an implantable version that would give glaucoma researchers unprecedented knowledge and control of IOP in rats and potentially larger animals.
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Affiliation(s)
- Simon A Bello
- Department of Chemical & Biomedical Engineering, University of South Florida, 4202 E Fowler Ave, Tampa, FL, 33620, USA
| | - Sharad Malavade
- Department of Ophthalmology, University of South Florida, Tampa, FL, 33620, USA
| | - Christopher L Passaglia
- Department of Chemical & Biomedical Engineering, University of South Florida, 4202 E Fowler Ave, Tampa, FL, 33620, USA.
- Department of Ophthalmology, University of South Florida, Tampa, FL, 33620, USA.
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Patel GC, Phan TN, Maddineni P, Kasetti RB, Millar JC, Clark AF, Zode GS. Dexamethasone-Induced Ocular Hypertension in Mice: Effects of Myocilin and Route of Administration. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:713-723. [PMID: 28167045 DOI: 10.1016/j.ajpath.2016.12.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 12/05/2016] [Accepted: 12/08/2016] [Indexed: 11/24/2022]
Abstract
Glucocorticoid (GC)-induced ocular hypertension (OHT) is a serious adverse effect of prolonged GC therapy that can lead to iatrogenic glaucoma and permanent vision loss. An appropriate mouse model can help us understand precise molecular mechanisms and etiology of GC-induced OHT. We therefore developed a novel, simple, and reproducible mouse model of GC-induced OHT. GC-induced myocilin expression in the trabecular meshwork (TM) has been suggested to play an important role in GC-induced OHT. We further determined whether myocilin contributes to GC-OHT. C57BL/6J mice received weekly periocular conjunctival fornix injections of a dexamethasone-21-acetate (DEX-Ac) formulation. Intraocular pressure (IOP) elevation was relatively rapid and significant, and correlated with reduced conventional outflow facility. Nighttime IOPs were higher in ocular hypertensive eyes compared to daytime IOPs. DEX-Ac treatment led to increased expression of fibronectin, collagen I, and α-smooth muscle actin in the TM in mouse eyes. No changes in body weight indicated no systemic toxicity associated with DEX-Ac treatment. Wild-type mice showed increased myocilin expression in the TM on DEX-Ac treatment. Both wild-type and Myoc-/- mice had equivalent and significantly elevated IOP with DEX-Ac treatment every week. In conclusion, our mouse model mimics many aspects of GC-induced OHT in humans, and we further demonstrate that myocilin does not play a major role in DEX-induced OHT in mice.
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Affiliation(s)
- Gaurang C Patel
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas
| | - Tien N Phan
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas
| | - Prabhavathi Maddineni
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas
| | - Ramesh B Kasetti
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas
| | - J Cameron Millar
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas
| | - Abbot F Clark
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas.
| | - Gulab S Zode
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas.
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Tsuchiya S, Higashide T, Toida K, Sugiyama K. The Role of Beta-Adrenergic Receptors in the Regulation of Circadian Intraocular Pressure Rhythm in Mice. Curr Eye Res 2017; 42:1013-1017. [PMID: 28121174 DOI: 10.1080/02713683.2016.1264605] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSE To investigate whether the elimination of β1- and β2-adrenergic receptors alters the diurnal intraocular pressure (IOP) rhythm in mice. MATERIALS AND METHODS β1-/β2-adrenergic receptor double-knockout and C57BL/6J mice were anesthetized intraperitoneally, with their IOPs measured via microneedle method. After entrainment to a 12-h light-dark (LD) cycle (light phase 6:00-18:00), IOPs were measured every 3 h from 9:00 to 24:00 (group 1, β1-/β2-adrenergic receptor double-knockout mice, n = 11; C57BL/6J, n = 15). The IOP measurements at 15:00 and 24:00 under a 12-h LD cycle and in the constant darkness (1 day and 8 days after exposure to darkness, respectively) were performed in another group of β1-/β2-adrenergic receptor double-knockout mice (group 2, n = 12). IOP variance throughout the day and mean IOP differences among time points were evaluated using a linear mixed model. RESULTS β1-/β2-adrenergic receptor double-knockout and C57BL/6J mice showed biphasic IOP curves, low during the light phase and high during the dark phase; the fluctuation was significant (P < 0.001). The peak IOP (18.7 ± 1.4 mmHg) occurred at 24:00 and the trough IOP (13.5 ± 1.5 mmHg) occurred at 15:00 in β1-/β2-adrenergic receptor double-knockout mice group. IOP curves of β1-/β2-adrenergic receptor double-knockout and C57BL/6J were nearly parallel, and the IOPs of β1-/β2-adrenergic receptor double-knockout mice were significantly higher than those of C57BL/6J mice (P < 0.001). Under constant dark (DD) conditions, IOP at 24:00 (18.1 ± 1.5 mmHg) was significantly higher than that at 15:00 (13.3 ± 1.2 mmHg) (P < 0.001). The transition from the LD cycle to DD environment produced no significant change in IOP (P = 0.728). CONCLUSIONS Elimination of both β1- and β2-adrenergic receptors did not disturb the biphasic diurnal IOP rhythm in mice.
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Affiliation(s)
- Shunsuke Tsuchiya
- a Department of Ophthalmology and Visual Science , Kanazawa University Graduate School of Medical Science , Kanazawa , Japan
| | - Tomomi Higashide
- a Department of Ophthalmology and Visual Science , Kanazawa University Graduate School of Medical Science , Kanazawa , Japan
| | - Kazunori Toida
- b Department of Anatomy , Kawasaki Medical School , Kurashiki , Japan.,c Research Center for Ultra-High Voltage Electron Microscopy , Osaka University , Ibaraki , Japan
| | - Kazuhisa Sugiyama
- a Department of Ophthalmology and Visual Science , Kanazawa University Graduate School of Medical Science , Kanazawa , Japan
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Dalvin LA, Fautsch MP. Analysis of Circadian Rhythm Gene Expression With Reference to Diurnal Pattern of Intraocular Pressure in Mice. Invest Ophthalmol Vis Sci 2015; 56:2657-63. [PMID: 25813988 DOI: 10.1167/iovs.15-16449] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine the expression of circadian rhythm clock genes in the iris-ciliary body complex of mice and their association with the diurnal pattern of intraocular pressure (IOP). METHODS Thirty wild-type C57BL/6 mice were acclimated to a 12-hour light-dark cycle. Intraocular pressure was measured with a rebound tonometer at six time points daily (circadian time [CT] 2, 6, 10, 14, 18, and 22 hours) for five consecutive days. On day 6, mice were euthanized at CT 2, 6, 10, 14, 18, and 22. Eyes were flash-frozen or fixed in 4% phosphate-buffered paraformaldehyde. Total RNA was extracted from the iris-ciliary body complex, and RNA expression of circadian rhythm genes Bmal1, Clock, Cry1, Cry2, Per1, and Per2 was assessed by quantitative real-time PCR. Fixed eyes were paraffin embedded, and immunohistochemistry was performed to localize corresponding proteins (BMAL1, CLOCK, CRY1, CRY2, PER1, and PER2). Linear regression analysis was performed to correlate gene expression with IOP. RESULTS Intraocular pressure demonstrated a consistent circadian pattern. The clock genes Bmal1, Clock, Cry1, Cry2, Per1, and Per2 showed a circadian pattern of expression in the iris-ciliary body complex of mice. Bmal1, Clock, Cry1, Per1, and Per2 gene expression demonstrated statistically significant correlations with diurnal variations of IOP. BMAL1, CLOCK, CRY1, CRY2, PER1, and PER2 proteins were found to be expressed locally in the nonpigmented epithelium of the ciliary body. CONCLUSIONS Expression patterns of candidate circadian rhythm genes correlates with the diurnal pattern variation of IOP in mouse eyes, indicating a possible mechanism of IOP regulation through these genes.
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Vidal-Sanz M, Valiente-Soriano FJ, Ortín-Martínez A, Nadal-Nicolás FM, Jiménez-López M, Salinas-Navarro M, Alarcón-Martínez L, García-Ayuso D, Avilés-Trigueros M, Agudo-Barriuso M, Villegas-Pérez MP. Retinal neurodegeneration in experimental glaucoma. PROGRESS IN BRAIN RESEARCH 2015; 220:1-35. [PMID: 26497783 DOI: 10.1016/bs.pbr.2015.04.008] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In rats and mice, limbar tissues of the left eye were laser-photocoagulated (LP) and ocular hypertension (OHT) effects were investigated 1 week to 6 months later. To investigate the innermost layers, retinas were examined in wholemounts using tracing from the superior colliculi to identify retinal ganglion cells (RGCs) with intact retrograde axonal transport, melanopsin immunodetection to identify intrinsically photosensitive RGCs (m(+)RGC), Brn3a immunodetection to identify most RGCs but not m(+)RGCs, RECA1 immunodetection to examine the inner retinal vessels, and DAPI staining to detect all nuclei in the GC layer. The outer retinal layers (ORLs) were examined in cross sections analyzed morphometrically or in wholemounts to study S- and L-cones. Innervation of the superior colliculi was examined 10 days to 14 weeks after LP with orthogradely transported cholera toxin subunit B. By 2 weeks, OHT resulted in pie-shaped sectors devoid of FG(+)RGCs or Brn3a(+)RGCs but with large numbers of DAPI(+)nuclei. Brn3a(+)RGCs were significantly greater than FG(+)RGCs, indicating the survival of large numbers of RGCs with their axonal transport impaired. The inner retinal vasculature showed no abnormalities that could account for the sectorial loss of RGCs. m(+)RGCs decreased to approximately 50-51% in a diffuse loss across the retina. Cross sections showed focal areas of degeneration in the ORLs. RGC loss at 1m diminished to 20-25% and did not progress further with time, whereas the S- and L-cone populations diminished progressively up to 6m. The retinotectal projection was reduced by 10 days and did not progress further. LP-induced OHT results in retrograde degeneration of RGCs and m(+)RGCs, severe damage to the ORL, and loss of retinotectal terminals.
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Affiliation(s)
- Manuel Vidal-Sanz
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain.
| | - Francisco J Valiente-Soriano
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Arturo Ortín-Martínez
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Francisco M Nadal-Nicolás
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Manuel Jiménez-López
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Manuel Salinas-Navarro
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Luis Alarcón-Martínez
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Diego García-Ayuso
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Marcelino Avilés-Trigueros
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Marta Agudo-Barriuso
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
| | - Maria P Villegas-Pérez
- Departamento de Oftalmología, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain
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Rat optic nerve head anatomy within 3D histomorphometric reconstructions of normal control eyes. Exp Eye Res 2015; 139:1-12. [PMID: 26021973 DOI: 10.1016/j.exer.2015.05.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 04/24/2015] [Accepted: 05/19/2015] [Indexed: 12/11/2022]
Abstract
The purpose of this study is to three-dimensionally (3D) characterize the principal macroscopic and microscopic relationships within the rat optic nerve head (ONH) and quantify them in normal control eyes. Perfusion-fixed, trephinated ONH from 8 normal control eyes of 8 Brown Norway Rats were 3D histomorphometrically reconstructed, visualized, delineated and parameterized. The rat ONH consists of 2 scleral openings, (a superior neurovascular and inferior arterial) separated by a thin connective tissue strip we have termed the "scleral sling". Within the superior opening, the nerve abuts a prominent extension of Bruch's Membrane (BM) superiorly and is surrounded by a vascular plexus, as it passes through the sclera, that is a continuous from the choroid into and through the dural sheath and contains the central retinal vein (CRV), (inferiorly). The inferior scleral opening contains the central retinal artery and three long posterior ciliary arteries which obliquely pass through the sclera to obtain the choroid. Bruch's Membrane Opening (BMO) is irregular and vertically elongated, enclosing the nerve (superiorly) and CRV and CRA (inferiorly). Overall mean BMO Depth, BMO Area, Choroidal Thickness and peripapillary Scleral Thickness were 29 μm, 56.5 × 10(3) μm(2), 57 μm and 104 μm respectively. Mean anterior scleral canal opening (ASCO) and posterior scleral canal opening (PSCO) radii were 201 ± 15 μm and 204 ± 16 μm, respectively. Mean optic nerve area at the ASCO and PSCO were 46.3 × 10(3)±4.4 × 10(3) μm(2) and 44.1 × 10(3)±4.5 × 10(3) μm(2) respectively. In conclusion, the 3D complexity of the rat ONH and the extent to which it differs from the primate have been under-appreciated within previous 2D studies. Properly understood, these anatomic differences may provide new insights into the relative susceptibilities of the rat and primate ONH to elevated intraocular pressure.
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Morrison JC, Cepurna WO, Johnson EC. Modeling glaucoma in rats by sclerosing aqueous outflow pathways to elevate intraocular pressure. Exp Eye Res 2015; 141:23-32. [PMID: 26003399 DOI: 10.1016/j.exer.2015.05.012] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Revised: 05/18/2015] [Accepted: 05/19/2015] [Indexed: 12/14/2022]
Abstract
Injection of hypertonic saline via episcleral veins toward the limbus in laboratory rats can produce elevated intraocular pressure (IOP) by sclerosis of aqueous humor outflow pathways. This article describes important anatomic characteristics of the rat optic nerve head (ONH) that make it an attractive animal model for human glaucoma, along with the anatomy of rat aqueous humor outflow on which this technique is based. The injection technique itself is also described, with the aid of a supplemental movie, including necessary equipment and specific tips to acquire this skill. Outcomes of a successful injection are presented, including IOP elevation and patterns of optic nerve injury. These concepts are then specifically considered in light of the use of this model to assess potential neuroprotective therapies. Advantages of the hypertonic saline model include a delayed and relatively gradual IOP elevation, likely reproduction of scleral and ONH stresses and strains that may be important in producing axonal injury, and its ability to be applied to any rat (and potentially mouse) strain, leaving the unmanipulated fellow eye as an internal control. Challenges include the demanding surgical skill required by the technique itself, a wide range of IOP response, and mild corneal clouding in some animals. However, meticulous application of the principles detailed in this article and practice will allow most researchers to attain this useful skill for studying cellular events of glaucomatous optic nerve damage.
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Affiliation(s)
- John C Morrison
- The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, USA.
| | - William O Cepurna
- The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, USA
| | - Elaine C Johnson
- The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, USA
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Abstract
Ocular hypertension is a risk factor for developing glaucoma, which consists of a group of optic neuropathies characterized by progressive degeneration of retinal ganglion cells and subsequent irreversible vision loss. Our understanding of how intraocular pressure damages the optic nerve is based on clinical measures of intraocular pressure that only gives a partial view of the dynamic pressure load inside the eye. Intraocular pressure varies over the course of the day and the oscillator regulating these daily changes has not yet been conclusively identified. The purpose of this study was to compare and contrast the circadian rhythms of intraocular pressure and body temperature in Brown Norway rats when these animals are housed in standard light-dark and continuous dim light (40-90 lux) conditions. The results from this study show that the temperature rhythm measured in continuous dim light drifted forward relative to external time, indicating that the rhythm was free running and being regulated by an internal biological clock. Also, the results show that there is a persistent, but dampened, circadian rhythm of intraocular pressure in continuous dim light and that the circadian rhythms of temperature and intraocular pressure are not synchronized by the same central oscillator. We conclude that once- or twice-daily clinical measures of intraocular pressure are insufficient to describe intraocular pressure dynamics. Similarly, our results indicate that, in experimental animal models of glaucoma, the common practice of housing animals in constant light does not necessarily eliminate the potential influence of intraocular pressure rhythms on the progression of nerve damage. Future studies should aim to determine whether an oscillator within the eye regulates the rhythm of intraocular pressure and to better characterize the impact of glaucoma on this rhythm.
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Affiliation(s)
- Diana C. Lozano
- College of Optometry, University of Houston, Houston, TX, USA
| | | | - Michael D. Twa
- College of Optometry, University of Houston, Houston, TX, USA
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Borrás T, Buie LK, Spiga MG, Carabana J. Prevention of nocturnal elevation of intraocular pressure by gene transfer of dominant-negative RhoA in rats. JAMA Ophthalmol 2015; 133:182-90. [PMID: 25412195 DOI: 10.1001/jamaophthalmol.2014.4747] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
IMPORTANCE We developed a gene transfer tool for the control of nocturnal elevated intraocular pressure (IOP). OBJECTIVE To demonstrate that inhibiting the trabecular meshwork RhoA pathway by delivering a mutated, dominant-negative RhoA gene (dnRhoA) carried inside a long-expressing recombinant virus would reduce nocturnal elevated IOP in a living animal. DESIGN AND SETTING We generated an optimized recombinant viral molecule by inserting a mutated RhoA complementary DNA with a translation enhancer-promoter into a specially designed plasmid containing mutated viral terminal repeats. We then generated the virus particle, self-complementary adeno-associated virus serotype 2 carrying the mutated gene (scAAV2.dnRhoA) and assessed its function in vitro by infecting primary human trabecular meshwork cells and in vivo by injecting living rats intracamerally with therapeutic and control viruses. Three different models of 12-hour light and dark cycles were used. Viruses were injected when animals showed the circadian dark IOP elevation. The IOP measurements were conducted with a tonometer at 2 to 4 hours after onset of the nocturnal and diurnal cycles. Values at preinjection time were used as baselines. Animals were euthanized at 4 to 8 weeks after injection. EXPOSURES Intraocular injection of rodent eyes with the recombinant viral vector scAAV2.dnRhoA. MAIN OUTCOMES AND MEASURES Nocturnal elevation of IOP blocked for prolonged periods by transferred RhoA gene. RESULTS By visual inspection, human trabecular meshwork cells infected with scAAV2.dnRhoA showed diminished stress fiber formation. Living rats exhibited a circadian IOP cycle that could be reset by adjusting light conditions to facilitate light and dark nocturnal IOP studies. A single-dose injection of scAAV2.dnRhoA into the rat eyes prevented elevation of IOP during the nocturnal cycle for at least 4 weeks (mean [SE], 9.2 [0.2] mm Hg light IOP and 9.6 [0.4] mm Hg dark IOP), while control eyes showed a significantly higher IOP over baseline (9.5 [0.4] mm Hg light IOP and 13.5 [0.3] mm Hg dark IOP). CONCLUSIONS AND RELEVANCE To our knowledge, this is the first example of a gene transfer strategy that prevents nocturnal IOP elevation in living animals for prolonged periods. Inhibiting the RhoA pathway upstream of Rho kinase with a safe gene drug could provide a new enhanced treatment for long-term management of elevated nocturnal IOP.
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Affiliation(s)
- Teresa Borrás
- Department of Ophthalmology, University of North Carolina at Chapel Hill School of Medicine
| | - LaKisha K Buie
- Department of Ophthalmology, University of North Carolina at Chapel Hill School of Medicine
| | - Maria-Grazia Spiga
- Department of Ophthalmology, University of North Carolina at Chapel Hill School of Medicine
| | - Juan Carabana
- Department of Ophthalmology, University of North Carolina at Chapel Hill School of Medicine
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Pirhan D, Yüksel N, Emre E, Cengiz A, Kürşat Yıldız D. Riluzole- and Resveratrol-Induced Delay of Retinal Ganglion Cell Death in an Experimental Model of Glaucoma. Curr Eye Res 2015; 41:59-69. [PMID: 25658983 DOI: 10.3109/02713683.2015.1004719] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
PURPOSE To evaluate the effects of the neuroprotective agents riluzole and resveratrol on the survival of retinal ganglion cells (RGCs) when administered alone or in combination. MATERIALS AND METHODS Experimental glaucoma was induced by injecting hyaluronic acid into the anterior chamber of Wistar albino rats weekly for a six-week period. Intraocular pressure was measured before and immediately after glaucoma induction. The neuroprotective effects of daily intraperitoneal injections of riluzole (8 mg/kg) and resveratrol (10 mg/kg) were evaluated and compared. After the six-week period, dextran tetramethylrhodamine was applied into the optic nerve and the density of surviving RGCs was evaluated by counting the labeled RGCs in whole mount retinas for retrograde labeling of RGCs. RESULTS The mean numbers of RGCs were significantly preserved in all treatment groups compared to the vehicle-treated glaucoma group (G). The mean number of RGCs in mm(2) were 1207 ± 56 in the control group (C), 404 ± 65 in G group, 965 ± 56 in riluzole-treated group in the early phase of glaucoma (E-Ri), 714 ± 25 in riluzole-treated group in the late phase of glaucoma (L-Ri), 735 ± 29 in resveratrol-treated group in the early phase of glaucoma (E-Re), 667 ± 20 in resveratrol-treated group in the late phase of glaucoma (L-Re), and 1071 ± 49 in riluzole and resveratrol combined-treated group in the early phase of glaucoma (E-RiRe group). CONCLUSIONS When used either alone or in combination, both riluzole and resveratrol, two agents with different mechanisms of action in glaucoma, significantly delayed RGC loss in this study's experimental glaucoma model.
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Affiliation(s)
| | | | - Esra Emre
- a Department of Ophthalmology , School of Medicine
| | - Abdulkadir Cengiz
- b Department of Technical Education , Technical Education Faculty , and
| | - Demir Kürşat Yıldız
- c Department of Pathology , School of Medicine, University of Kocaeli , Kocaeli , Turkey
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Bunker S, Holeniewska J, Vijay S, Dahlmann-Noor A, Khaw P, Ng YS, Shima D, Foxton R. Experimental glaucoma induced by ocular injection of magnetic microspheres. J Vis Exp 2015. [PMID: 25742031 PMCID: PMC4354616 DOI: 10.3791/52400] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Progress in understanding the pathophysiology, and providing novel treatments for glaucoma is dependent on good animal models of the disease. We present here a protocol for elevating intraocular pressure (IOP) in the rat, by injecting magnetic microspheres into the anterior chamber of the eye. The use of magnetic particles allows the user to manipulate the beads into the iridocorneal angle, thus providing a very effective blockade of fluid outflow from the trabecular meshwork. This leads to long-lasting IOP rises, and eventually neuronal death in the ganglion cell layer (GCL) as well as optic nerve pathology, as seen in patients with the disease. This method is simple to perform, as it does not require machinery, specialist surgical skills, or many hours of practice to perfect. Furthermore, the pressure elevations are very robust, and reinjection of the magnetic microspheres is not usually required unlike in some other models using plastic beads. Additionally, we believe this method is suitable for adaptation for the mouse eye.
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Affiliation(s)
- Shannon Bunker
- Ocular Biology and Therapeutics, University College London Institute of Ophthalmology
| | - Joanna Holeniewska
- Ocular Biology and Therapeutics, University College London Institute of Ophthalmology
| | | | | | - Peng Khaw
- University College London Institue of Ophthalmology; NIHR Biomedical Research Centre, Moorfields Eye Hospital
| | - Yin-Shan Ng
- Schepens Eye Research Institute, Harvard Medical School
| | - David Shima
- Ocular Biology and Therapeutics, University College London Institute of Ophthalmology; Hoffman-La Roche
| | - Richard Foxton
- Ocular Biology and Therapeutics, University College London Institute of Ophthalmology;
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Ortín-Martínez A, Salinas-Navarro M, Nadal-Nicolás FM, Jiménez-López M, Valiente-Soriano FJ, García-Ayuso D, Bernal-Garro JM, Avilés-Trigueros M, Agudo-Barriuso M, Villegas-Pérez MP, Vidal-Sanz M. Laser-induced ocular hypertension in adult rats does not affect non-RGC neurons in the ganglion cell layer but results in protracted severe loss of cone-photoreceptors. Exp Eye Res 2015; 132:17-33. [PMID: 25576772 DOI: 10.1016/j.exer.2015.01.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 11/19/2014] [Accepted: 01/07/2015] [Indexed: 01/09/2023]
Abstract
To investigate the long-term effects of laser-photocoagulation (LP)-induced ocular hypertension (OHT) in the innermost and outermost (outer-nuclear and outer segment)-retinal layers (ORL). OHT was induced in the left eye of adult rats. To investigate the ganglion cell layer (GCL) wholemounts were examined at 1, 3 or 6 months using Brn3a-immunodetection to identify retinal ganglion cells (RGCs) and DAPI-staining to detect all nuclei in this layer. To study the effects of LP on the ORL up to 6 months, retinas were: i) fresh extracted to quantify the levels of rod-, S- and L-opsin; ii) cut in cross-sections for morphometric analysis, or; iii) prepared as wholemounts to quantify and study retinal distributions of entire populations of RGCs (retrogradely labeled with fluorogold, FG), S- and L-cones (immunolabeled). OHT resulted in wedge-like sectors with their apex on the optic disc devoid of Brn3a(+)RGCs but with large numbers of DAPI(+)nuclei. The levels of all opsins diminished by 2 weeks and further decreased to 20% of basal-levels by 3 months. Cross-sections revealed focal areas of ORL degeneration. RGC survival at 15 days represented approximately 28% and did not change with time, whereas the S- and L-cone populations diminished to 65% and 80%, or to 20 and 35% at 1 or 6 months, respectively. In conclusion, LP induces in the GCL selective RGCs loss that does not progress after 1 month, and S- and L-cone loss that progresses for up to 6 months. Thus, OHT results in severe damage to both the innermost and the ORL.
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Affiliation(s)
- Arturo Ortín-Martínez
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - Manuel Salinas-Navarro
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - Francisco Manuel Nadal-Nicolás
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - Manuel Jiménez-López
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - Francisco Javier Valiente-Soriano
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - Diego García-Ayuso
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - José Manuel Bernal-Garro
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - Marcelino Avilés-Trigueros
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - Marta Agudo-Barriuso
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - María Paz Villegas-Pérez
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain
| | - Manuel Vidal-Sanz
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain.
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RhoA GTPase-induced ocular hypertension in a rodent model is associated with increased fibrogenic activity in the trabecular meshwork. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 185:496-512. [PMID: 25499974 DOI: 10.1016/j.ajpath.2014.10.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 09/03/2014] [Accepted: 10/07/2014] [Indexed: 02/08/2023]
Abstract
Ocular hypertension arising from increased resistance to aqueous humor (AH) outflow through the trabecular meshwork is a primary risk factor for open-angle glaucoma, a leading cause of blindness. Ongoing efforts have found little about the molecular and cellular bases of increased resistance to AH outflow through the trabecular meshwork in ocular hypertension patients. To test the hypothesis that dysregulated Rho GTPase signaling and a resulting fibrotic activity within the trabecular meshwork may result in ocular hypertension, we investigated the effects of expressing a constitutively active RhoA GTPase (RhoAV14) in the AH outflow pathway in Sprague-Dawley rats by using lentiviral vector-based gene delivery. Rats expressing RhoAV14 in the iridocorneal angle exhibited a significantly elevated intraocular pressure. Elevated intraocular pressure in the RhoAV14-expressing rats was associated with fibrotic trabecular meshwork and increased levels of F-actin, phosphorylated myosin light chain, α-smooth muscle actin, collagen-1A, and total collagen in the trabecular AH outflow pathway. Most of these changes were ameliorated by topical application of Rho kinase inhibitor. Human autopsy eyes from patients with glaucoma exhibited significant increases in levels of collagen-1A and total collagen in the trabecular AH outflow pathway. Collectively, these observations indicate that increased fibrogenic activity because of dysregulated RhoA GTPase activity in the trabecular AH outflow pathway increases intraocular pressure in a Rho kinase-dependent manner.
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40
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Giannetto C, Fazio F, Panzera M, Alberghina D, Piccione G. Comparison of rectal and vaginal temperature daily rhythm in dogs (Canis familiaris) under different photoperiod. BIOL RHYTHM RES 2014. [DOI: 10.1080/09291016.2014.963946] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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41
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McMahon DG, Iuvone PM, Tosini G. Circadian organization of the mammalian retina: from gene regulation to physiology and diseases. Prog Retin Eye Res 2013; 39:58-76. [PMID: 24333669 DOI: 10.1016/j.preteyeres.2013.12.001] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 11/27/2013] [Accepted: 12/01/2013] [Indexed: 01/27/2023]
Abstract
The retinal circadian system represents a unique structure. It contains a complete circadian system and thus the retina represents an ideal model to study fundamental questions of how neural circadian systems are organized and what signaling pathways are used to maintain synchrony of the different structures in the system. In addition, several studies have shown that multiple sites within the retina are capable of generating circadian oscillations. The strength of circadian clock gene expression and the emphasis of rhythmic expression are divergent across vertebrate retinas, with photoreceptors as the primary locus of rhythm generation in amphibians, while in mammals clock activity is most robust in the inner nuclear layer. Melatonin and dopamine serve as signaling molecules to entrain circadian rhythms in the retina and also in other ocular structures. Recent studies have also suggested GABA as an important component of the system that regulates retinal circadian rhythms. These transmitter-driven influences on clock molecules apparently reinforce the autonomous transcription-translation cycling of clock genes. The molecular organization of the retinal clock is similar to what has been reported for the SCN although inter-neural communication among retinal neurons that form the circadian network is apparently weaker than those present in the SCN, and it is more sensitive to genetic disruption than the central brain clock. The melatonin-dopamine system is the signaling pathway that allows the retinal circadian clock to reconfigure retinal circuits to enhance light-adapted cone-mediated visual function during the day and dark-adapted rod-mediated visual signaling at night. Additionally, the retinal circadian clock also controls circadian rhythms in disk shedding and phagocytosis, and possibly intraocular pressure. Emerging experimental data also indicate that circadian clock is also implicated in the pathogenesis of eye disease and compelling experimental data indicate that dysfunction of the retinal circadian system negatively impacts the retina and possibly the cornea and the lens.
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Affiliation(s)
- Douglas G McMahon
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - P Michael Iuvone
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, GA, USA; Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
| | - Gianluca Tosini
- Neuroscience Institute and Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, 30310 GA, USA.
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42
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Kwong JMK, Vo N, Quan A, Nam M, Kyung H, Yu F, Piri N, Caprioli J. The dark phase intraocular pressure elevation and retinal ganglion cell degeneration in a rat model of experimental glaucoma. Exp Eye Res 2013; 112:21-8. [PMID: 23603611 DOI: 10.1016/j.exer.2013.04.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 03/28/2013] [Accepted: 04/10/2013] [Indexed: 10/26/2022]
Abstract
Intraocular pressure (IOP) elevation is considered as a major risk factor causing the progression of vision deterioration in glaucoma. Although it is known that the IOP level changes widely throughout the day and night, how the dark or light phase IOP elevation contributes to retinal ganglion cell (RGC) degeneration is still largely unclear. To examine the profile of IOP, modified laser photocoagulation was applied to the trabecular meshwork of Brown Norway rats and both light and dark phase IOPs were monitored approximately 1-2 times a week. The relationship between IOP elevation and RGC degeneration was investigated while RGC body loss was analyzed with Rbpms immunolabeling on retinal wholemount and axonal injury in the optic nerve was semi-quantified. The baseline awake dark and light IOPs were 30.4 ± 2.7 and 20.2 ± 2.1 mmHg respectively. The average dark IOP was increased to 38.2 ± 3.2 mmHg for five weeks after the laser treatment on 270° trabecular meshwork. However, there was no significant loss of RGC body and axonal injury. After laser treatment on 330° trabecular meshwork, the dark and light IOPs were significantly increased to 43.8 ± 4.6 and 23 ± 3.7 mmHg respectively for 5 weeks. The cumulative dark and light IOP elevations were 277 ± 86 and 113 ± 50 mmHg days respectively while the cumulative total (light and dark) IOP elevation was 213 ± 114 mmHg days. After 5 weeks, regional RGC body loss of 29.5 ± 15.5% and moderate axonal injury were observed. Axonal injury and loss of RGC body had a high correlation with the cumulative total IOP elevation (R(2) = 0.60 and 0.65 respectively). There was an association between the cumulative dark IOP elevation and RGC body loss (R(2) = 0.37) and axonal injury (R(2) = 0.51) whereas the associations between neuronal damages and the cumulative light IOP elevation were weak (for RGC body loss, R(2) = 0.01; for axonal injury, R(2) = 0.26). Simple linear regression model analysis showed statistical significance for the relationships between the total cumulative IOP elevation and RGC body loss (P = 0.009), and axonal injury (P = 0.016). To examine the role of light and dark IOP elevation in RGC body loss and axonal injury, analyses for the association between different light/dark IOP factors and percentage of RGC body loss/axonal injury grading were performed and only the association between the cumulative dark IOP elevation and axonal injury showed statistical significance (P = 0.033). The findings demonstrated that the cumulative total (light and dark) IOP elevation is a risk factor to RGC degeneration in a rat model of experimental glaucoma using modified partial laser photocoagulation at 330° trabecular meshwork. Further investigations are required to understand the role of longer term light and dark phase IOP elevation contributing to the progression of degeneration in different compartments of RGCs.
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Affiliation(s)
- Jacky M K Kwong
- Jules Stein Eye Institute, David Geffen School of Medicine, University of California Los Angeles, 100 Stein Plaza, Los Angeles, CA 90095, United States.
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43
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Bui BV, He Z, Vingrys AJ, Nguyen CTO, Wong VHY, Fortune B. Using the electroretinogram to understand how intraocular pressure elevation affects the rat retina. J Ophthalmol 2013; 2013:262467. [PMID: 23431417 PMCID: PMC3570935 DOI: 10.1155/2013/262467] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 10/24/2012] [Indexed: 11/17/2022] Open
Abstract
Intraocular pressure (IOP) elevation is a key risk factor for glaucoma. Our understanding of the effect that IOP elevation has on the eye has been greatly enhanced by the application of the electroretinogram (ERG). In this paper, we describe how the ERG in the rodent eye is affected by changes in IOP magnitude, duration, and number of spikes. We consider how the variables of blood pressure and age can modify the effect of IOP elevation on the ERG. Finally, we contrast the effects that acute and chronic IOP elevation can have on the rodent ERG.
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Affiliation(s)
- Bang V. Bui
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC 3010, Australia
| | - Zheng He
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC 3010, Australia
| | - Algis J. Vingrys
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC 3010, Australia
| | - Christine T. O. Nguyen
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC 3010, Australia
| | - Vickie H. Y. Wong
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC 3010, Australia
| | - Brad Fortune
- Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, OR 97232, USA
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44
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Vidal-Sanz M, Salinas-Navarro M, Nadal-Nicolás FM, Alarcón-Martínez L, Valiente-Soriano FJ, Miralles de Imperial J, Avilés-Trigueros M, Agudo-Barriuso M, Villegas-Pérez MP. Understanding glaucomatous damage: Anatomical and functional data from ocular hypertensive rodent retinas. Prog Retin Eye Res 2012; 31:1-27. [DOI: 10.1016/j.preteyeres.2011.08.001] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 08/23/2011] [Accepted: 08/24/2011] [Indexed: 12/24/2022]
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Kwong JMK, Quan A, Kyung H, Piri N, Caprioli J. Quantitative analysis of retinal ganglion cell survival with Rbpms immunolabeling in animal models of optic neuropathies. Invest Ophthalmol Vis Sci 2011; 52:9694-702. [PMID: 22110060 DOI: 10.1167/iovs.11-7869] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To investigate whether a recently described retinal ganglion cell (RGC) marker Rbpms (RNA binding protein with multiple splicing) could be used for RGC quantification in various models of RGC degeneration. METHODS Optic nerve crush, excitotoxicity, and elevated intraocular pressure (IOP) rat models were used. Topographic analysis of Rbpms immunolabeling was performed on retinal wholemounts. Retrograde labelings with Fluorogold (FG) and III β-tubulin immunohistochemistry were compared. RESULTS In the optic nerve crush model, 37%, 87%, and 93% of Rbpms-positive cells were lost 1, 2, and 4 weeks, respectively. Significant loss of Rbpms-positive cells was noted 1 week after intravitreal injection of 12, 30, and 120 nmol N-methyl-d-aspartate (NMDA), whereas coinjection of 120 nmol of NMDA along with MK-801 increased the cell number from 10% to 59%. Over 95% of Rbpms-positive cells were FG- and III β-tubulin-positive after injury caused by optic nerve crush and NMDA injection. In rats with elevated IOP, induced by trabecular laser photocoagulation, there was a significant loss of Rbpms-positive cells compared with that of contralateral controls (P = 0.0004), and cumulative IOP elevation showed a strong linear relationship with the quantification of RGCs by Rbpms immunolabeling and retrograde labeling with FG. More than 99% of the remaining Rbpms-positive cells were double-labeled with FG. CONCLUSIONS Rbpms can reliably be used as an RGC marker for quantitative evaluation in rat models of RGC degeneration, regardless of the nature and the location of the primary site of the injury and the extent of neurodegeneration.
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Affiliation(s)
- Jacky M K Kwong
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California 90095, USA.
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Almasieh M, Lieven CJ, Levin LA, Di Polo A. A cell-permeable phosphine-borane complex delays retinal ganglion cell death after axonal injury through activation of the pro-survival extracellular signal-regulated kinases 1/2 pathway. J Neurochem 2011; 118:1075-86. [PMID: 21749374 PMCID: PMC3166386 DOI: 10.1111/j.1471-4159.2011.07382.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The reactive oxygen species (ROS) superoxide has been recognized as a critical signal triggering retinal ganglion cell (RGC) death after axonal injury. Although the downstream targets of superoxide are unknown, chemical reduction of oxidized sulfhydryls has been shown to be neuroprotective for injured RGCs. On the basis of this, we developed novel phosphine-borane complex compounds that are cell permeable and highly stable. Here, we report that our lead compound, bis (3-propionic acid methyl ester) phenylphosphine borane complex 1 (PB1) promotes RGC survival in rat models of optic nerve axotomy and in experimental glaucoma. PB1-mediated RGC neuroprotection did not correlate with inhibition of stress-activated protein kinase signaling, including apoptosis stimulating kinase 1 (ASK1), c-jun NH2-terminal kinase (JNK) or p38. Instead, PB1 led to a striking increase in retinal BDNF levels and downstream activation of the extracellular signal-regulated kinases 1/2 (ERK1/2) pathway. Pharmacological inhibition of ERK1/2 entirely blocked RGC neuroprotection induced by PB1. We conclude that PB1 protects damaged RGCs through activation of pro-survival signals. These data support a potential cross-talk between redox homeostasis and neurotrophin-related pathways leading to RGC survival after axonal injury.
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Affiliation(s)
- Mohammadali Almasieh
- Department of Pathology and Cell Biology and Groupe de Recherche sur le Système Nerveux Central (GRSNC), University of Montreal, Montreal, Quebec, Canada
| | - Christopher J. Lieven
- Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Leonard A. Levin
- Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
- Maisonneuve-Rosemont Research Center and Department of Ophthalmology, University of Montreal, Montreal, Quebec, Canada
| | - Adriana Di Polo
- Department of Pathology and Cell Biology and Groupe de Recherche sur le Système Nerveux Central (GRSNC), University of Montreal, Montreal, Quebec, Canada
- Maisonneuve-Rosemont Research Center and Department of Ophthalmology, University of Montreal, Montreal, Quebec, Canada
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47
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Cuny CS, Joachim SC, Gramlich OW, Gottschling PF, Pfeiffer N, Grus FH. Repeated intraocular pressure measurement in awake Lewis rats does not bias retinal ganglion cell survival. Curr Eye Res 2011; 35:1034-9. [PMID: 20958192 DOI: 10.3109/02713683.2010.498654] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE The TonoPen applanation tonometry is an established method for intraocular pressure (IOP) measurement. The IOP is one of the main variables affecting retinal ganglion cell (RGC) loss in experimental animal models in ophthalmology and the main risk factor for human glaucoma. In this study, we examined if IOP measurements with the TonoPen itself lead to retinal ganglion cell loss or any other possible retina damages, such as intraocular bleedings or ablation, in Lewis rats. METHODS Three groups of rats (n = 5 each) were formed. IOP monitoring, using a TonoPen XL, was performed on groups 1 and 3. Animals in groups 1 and 2 received funduscopies before and after one and two weeks of the study, in order to detect possible abnormalities. After two weeks, retinal flatmounts were stained to detect ganglion cells. RGCs were manually counted in eight predefined areas to compare mean RGC densities between groups 1 and 2 (IOP readings vs. no readings), using student t-test. RESULTS No significant difference in RGC density between animals that underwent IOP readings and controls could be observed (p = 0.8). As expected, no IOP alterations were monitored in groups 1 and 3 throughout the study. No retinal abnormalities, such as bleeding or retina ablation, were detectable. CONCLUSION We could detect no effects on retinal ganglion cell survival in Lewis rats or any other damages to the retina caused by IOP measurements using a TonoPen XL. This study proposes that repeated applanation tonometry does not affect RGC numbers, one of the main monitored variables in most glaucoma model studies. Therefore, the use of a TonoPen XL for repeated IOP monitoring in Lewis rats can be considered harmless.
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Affiliation(s)
- C S Cuny
- Experimental Ophthalmology, Department of Ophthalmology, University Medical Center, Johannes Gutenberg University, Mainz, Germany
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48
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Marina N, Bull ND, Martin KR. A semiautomated targeted sampling method to assess optic nerve axonal loss in a rat model of glaucoma. Nat Protoc 2010; 5:1642-51. [PMID: 20885376 DOI: 10.1038/nprot.2010.128] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We have developed a fast, reliable and easily reproducible semiautomated quantitative damage grading scheme to assess axonal loss in the optic nerve after inducing ocular hypertension using a laser glaucoma model in adult rats. This targeted sampling method has been validated against complete axon counts, and compares favorably with a conventional, random sampling, semiquantitative method. In addition, we present a standardized method to quantify axons in a semiautomated way, using freely available ImageJ software, and describe in detail the method used to induce glaucoma. Our techniques can be easily implemented in any laboratory, thanks to the public availability of the software and the simplicity of the method. Depending on the number of animals used in a particular study, the whole process from experimental elevation of intraocular pressure to tissue processing and data analysis should take ∼40 d.
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49
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Morrison JC, Cepurna Ying Guo WO, Johnson EC. Pathophysiology of human glaucomatous optic nerve damage: insights from rodent models of glaucoma. Exp Eye Res 2010; 93:156-64. [PMID: 20708000 DOI: 10.1016/j.exer.2010.08.005] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 07/28/2010] [Accepted: 08/03/2010] [Indexed: 10/19/2022]
Abstract
Understanding mechanisms of glaucomatous optic nerve damage is essential for developing effective therapies to augment conventional pressure-lowering treatments. This requires that we understand not only the physical forces in play, but the cellular responses that translate these forces into axonal injury. The former are best understood by using primate models, in which a well-developed lamina cribrosa, peripapillary sclera and blood supply are most like that of the human optic nerve head. However, determining cellular responses to elevated intraocular pressure (IOP) and relating their contribution to axonal injury require cell biology techniques, using animals in numbers sufficient to perform reliable statistical analyses and draw meaningful conclusions. Over the years, models of chronically elevated IOP in laboratory rats and mice have proven increasingly useful for these purposes. While lacking a distinct collagenous lamina cribrosa, the rodent optic nerve head (ONH) possesses a cellular arrangement of astrocytes, or glial lamina, that ultrastructurally closely resembles that of the primate. Using these tools, major insights have been gained into ONH and the retinal cellular responses to elevated IOP that, in time, can be applied to the primate model and, ultimately, human glaucoma.
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Affiliation(s)
- John C Morrison
- The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, CERES, 3375 SW Terwilliger Bvld, Portland, OR 97239, USA.
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50
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PICCIONE G, GIANNETTO C, FAZIO F, GIUDICE E. Influence of Different Artificial Lighting Regimes on Intraocular Pressure Circadian Profile in the Dog ( Canis familiaris). Exp Anim 2010; 59:215-23. [DOI: 10.1538/expanim.59.215] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Affiliation(s)
- Giuseppe PICCIONE
- Department of Experimental Sciences and Applied Biotechnology, Laboratory of Veterinary Chronophysiology, Faculty of Veterinary Medicine, University of Messina
| | - Claudia GIANNETTO
- Department of Experimental Sciences and Applied Biotechnology, Laboratory of Veterinary Chronophysiology, Faculty of Veterinary Medicine, University of Messina
| | - Francesco FAZIO
- Department of Experimental Sciences and Applied Biotechnology, Laboratory of Veterinary Chronophysiology, Faculty of Veterinary Medicine, University of Messina
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