Penetration depth of corneal cross-linking with riboflavin and UV-A (CXL) in horses and rabbits.
Abstract: CXL penetration depth is an important variable influencing clinical treatment effect and safety. The purposes of this study were to determine the penetration depth of CXL in rabbit and equine corneas in epithelium-on and epithelium-off procedures and to assess an ex vivo fluorescent biomarker staining assay for objective assessment of CXL penetration depth. Methods: CXL treatment was performed according to a standardized protocol on 21 and 17 rabbit eyes and on 12 and 10 equine eyes with and without debridement, respectively. Control corneas were treated similarly, but not exposed to CXL. Hemicorneas were stained with either phalloidin and DAPI to visualize intracellular F-actin and nuclei, or with hematoxylin and eosin. Loss of actin staining was measured and compared between groups. Results: Epithelium-off CXL caused a median actin cytoskeleton loss with a demarcation at 274 μm in rabbits and 173 μm in horses. In non-CXL-treated controls, we observed a median actin cytoskeleton loss with a demarcation at 134 μm in rabbits and 149 μm in horses. No effect was detected in the epithelium-on procedure. Conclusions: CXL penetration depth, as determined by a novel ex vivo fluorescent assay, shows clear differences between species. A distinct effect was observed following epithelium-off CXL treatment in the anterior stroma of rabbits, but no different effect was observed in horses in comparison with nontreated controls. Different protocols need to be established to effectively treat equine patients with infectious corneal disease.
© 2015 American College of Veterinary Ophthalmologists.
Publication Date: 2015-07-27 PubMed ID: 26215873DOI: 10.1111/vop.12301Google Scholar: Lookup
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- Journal Article
Summary
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The research investigates the penetration depth of corneal cross-linking (CXL) treatment with riboflavin and UV-A in horses and rabbits. It reveals that the technique’s penetration depth varies between species and is significantly influenced by whether the corneal epithelium is removed or left intact during the process.
Study Overview
- The study was driven by the need to determine the penetration depth of corneal cross-linking (CXL) in horses and rabbits. This is important in understanding its clinical effectiveness and safety.
- The researchers also aimed to evaluate the use of an ex vivo fluorescent biomarker staining assay for objectively measuring CXL penetration depth.
- The experiment involved 21 rabbit eyes and 12 horse eyes, where CXL treatment was performed with the epithelium intact. For the other set of 17 rabbit eyes and 10 horse eyes, the corneal epithelium was removed before CXL treatment.
- The treated eyes were then compared against a control group that underwent similar procedures but were not exposed to CXL.
Methods and Results
- CXL treatment on the animals’ eyes was carried out as per a standardized protocol.
- The treated corneas were stained with phalloidin and DAPI to visualize intracellular F-actin and nuclei, while others were stained with hematoxylin and eosin.
- Measurements were carried out to assess the loss of actin staining, which would indicate the depth of CXL penetration.
- Results showed a median actin loss with a demarcation at 274μm in rabbits and 173μm in horses for epithelium-off CXL procedures. For the non-CXL-treated controls, the median actin loss demarcation was at 134μm in rabbits and 149μm in horses.
- Importantly, no impact was detected when the corneal epithelium was left intact during CXL treatment (epithelium-on).
Conclusion
- The study concluded that the penetration depth of CXL, as indicated by the ex vivo fluorescent assay test, varies between species.
- It was found that the epithelium-off CXL treatment caused a distinct effect in rabbit’s anterior stroma but no such effect was observed in horses, compared to the untreated control.
- These differences imply a need for separate treatment protocols for equine patients who may have infectious corneal disease.
Cite This Article
APA
Gallhoefer NS, Spiess BM, Guscetti F, Hilbe M, Hartnack S, Hafezi F, Pot SA.
(2015).
Penetration depth of corneal cross-linking with riboflavin and UV-A (CXL) in horses and rabbits.
Vet Ophthalmol, 19(4), 275-284.
https://doi.org/10.1111/vop.12301 Publication
Researcher Affiliations
- Augen Vet, Lindenthalguertel 83, 50935, Cologne, Germany.
- Division of Ophthalmology, Equine Department, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse, 260, 8057, Zurich, Switzerland.
- Center for Clinical Studies, Vetsuisse Faculty, University of Zurich Winterthurerstrasse, 260, 8057, Zurich, Switzerland.
- Division of Ophthalmology, Equine Department, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse, 260, 8057, Zurich, Switzerland.
- Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich Winterthurerstrasse, 268, 8057, Zurich, Switzerland.
- Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich Winterthurerstrasse, 268, 8057, Zurich, Switzerland.
- Division of Veterinary Epidemiology, Vetsuisse Faculty, University of Zurich Winterthurerstrasse, 260, 8057, Zurich, Switzerland.
- Laboratory for Ocular Cell Biology, University of Geneva Rue Alcide-Jentzer, 22, CH-1211, Geneva 14, Switzerland.
- Department of Ophthalmology, University of Southern California, 1450 San Pablo St., Los Angeles, CA 90033, USA.
- The ELZA Institute AG, Webereistrasse 2, 8953 Dietikon, Zurich, Switzerland.
- Division of Ophthalmology, Equine Department, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse, 260, 8057, Zurich, Switzerland.
MeSH Terms
- Animals
- Biomarkers
- Cell Death
- Cornea / physiology
- Cross-Linking Reagents
- Fluorescent Dyes
- Horses
- Photosensitizing Agents / pharmacology
- Rabbits
- Riboflavin / pharmacology
- Tissue Culture Techniques
- Ultraviolet Rays
Citations
This article has been cited 8 times.- Kowalska M, Mischi E, Stoma S, Nørrelykke SF, Hartnack S, Pot SA. How Modifications of Corneal Cross-Linking Protocols Influence Corneal Resistance to Enzymatic Digestion and Treatment Depth.. Transl Vis Sci Technol 2023 May 1;12(5):18.
- Lazareva Y, Rayisyan M, Mironova E. Features of the clinical picture of keratitis in horses with different forms of the course of the disease.. Open Vet J 2022 Nov-Dec;12(6):830-838.
- Suter A, Schmitt S, Hübschke E, Kowalska M, Hartnack S, Pot S. The bactericidal effect of two photoactivated chromophore for keratitis-corneal crosslinking protocols (standard vs. accelerated) on bacterial isolates associated with infectious keratitis in companion animals.. BMC Vet Res 2022 Aug 17;18(1):317.
- Mun J, Kim TY, Myung D, Hahn SK. Smart contact lens containing hyaluronate-rose bengal conjugate for biophotonic myopia vision correction.. Biomater Sci 2022 Aug 24;10(17):4997-5005.
- Lores M, Rakestraw P, De Rijck M, Yarbrough T. Use of autologous fascia lata graft to repair a complex corneal ulcer in a mare.. Ir Vet J 2020;73:7.
- Perazzi A, Gomiero C, Corain L, Iacopetti I, Grisan E, Lombardo M, Lombardo G, Salvalaio G, Contin R, Patruno M, Martinello T, Peruffo A. An Assay System to Evaluate Riboflavin/UV-A Corneal Phototherapy Efficacy in a Porcine Corneal Organ Culture Model.. Animals (Basel) 2020 Apr 23;10(4).
- Yun SH, Chernyak D. Brillouin microscopy: assessing ocular tissue biomechanics.. Curr Opin Ophthalmol 2018 Jul;29(4):299-305.
- Marlo TL, Giuliano EA, Sharma A, Mohan RR. Development of a novel ex vivo equine corneal model.. Vet Ophthalmol 2017 Jul;20(4):288-293.
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