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Home / Equine Research Bank / Vet Ophthalmol / Optimizing corneal riboflavin administration in ex vivo hors...
Veterinary ophthalmology2020; 23(5); 840-848; doi: 10.1111/vop.12807

Optimizing corneal riboflavin administration in ex vivo horse, dog, rabbit, and pig samples for use in corneal collagen cross-linking.

Abstract: Determine optimal iontophoresis times for riboflavin delivery to the corneal stroma across different species and compare these to corneal injection. Methods: Ex vivo horse, dog, rabbit, and pig globes were treated with riboflavin administered with either iontophoresis for 2.5-20 minutes with or without corneal epithelium; or with purpose-designed precise corneal injection (PCI) application with intact epithelium. Immediately following riboflavin administration, samples were harvested, frozen, and sectioned. Riboflavin penetration was imaged using fluorescence microscopy. Results: Horse samples processed with iontophoresis without epithelium for 2.5, 5, and 7.5 minutes, and processed with intact epithelium for 20 minutes, had mean percent stromal penetration (%SP ) of 63.4%, 93.8%, 100.0%, and 0.0% (respectively). Dog samples processed with iontophoresis without epithelium for 2.5 and 5 minutes, had %SP of 60.7% and 82.1% (respectively). Pig samples processed with iontophoresis for 5 minutes without and with epithelium had %SP of 63.3% and 35.1% (respectively). Rabbit samples processed with iontophoresis without epithelium for 2.5 and 5 minutes, had %SP of 81.8% and 100.0% (respectively). For all injected volumes, riboflavin was observed spanning throughout the corneal stroma, and lamellar separation was noted surrounding all sites of injection. Conclusions: Both iontophoresis and injection via PCI needles provide efficient and effective means of riboflavin administration in ex vivo horse, dog, rabbit, and pig corneas. Epithelial debridement is required for stromal delivery of riboflavin using iontophoresis in horses. Following epithelial removal, riboflavin penetrated through the horse corneal stroma faster than all other species tested.
© 2020 American College of Veterinary Ophthalmologists.
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Publication Date: 2020-07-23 PubMed ID: 32702180DOI: 10.1111/vop.12807Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research focused on determining the best iontophoresis times for the delivery of riboflavin into the corneal stroma among different species like horses, dogs, rabbits, and pigs, and compared them with those using corneal injection.

Research Methods

  • This study utilized ex vivo samples of horse, dog, rabbit, and pig globes. The globes were treated with riboflavin, which was administered in one of two ways — either with iontophoresis ranging from 2.5 to 20 minutes, with or without corneal epithelium, or with a specially designed precise corneal injection (PCI) application with an intact epithelium.
  • Upon riboflavin administration, the samples were harvested, frozen, and sectioned for further analysis. The penetration of riboflavin was examined using fluorescence microscopy.

Results

  • The results showed varying degrees of riboflavin penetration into the corneal stroma across the different species tested. For horse samples, iontophoresis without epithelium at 2.5, 5, and 7.5 minutes resulted in stromal penetration rates of 63.4%, 93.8%, and 100.0%, respectively. The same procedure with an intact epithelium resulted in no stromal penetration after 20 minutes.
  • For dog samples, percent stromal penetration (SP) after iontophoresis without epithelium for 2.5 and 5 minutes were 60.7% and 82.1%, respectively.
  • Pig samples showed SP of 63.3% after 5 minutes of iontophoresis without epithelium, and 35.1% with epithelium.
  • Rabbit samples treated via iontophoresis without epithelium for 2.5 and 5 minutes showed SP of 81.8% and 100.0%, respectively.
  • All samples examined using PCI revealed that riboflavin spanned throughout the corneal stroma. Furthermore, a separation in the lamellar layers was observed at all injection sites.

Conclusions

  • The findings of this study suggested that both iontophoresis and injection via PCI needles offer efficient and effective means of riboflavin delivery in ex vivo horse, dog, rabbit, and pig corneas. For iontophoresis in horses, removal of the epithelial layer was necessary for stromal delivery of riboflavin.
  • Moreover, once the epithelium had been removed, riboflavin was observed to penetrate through the horse corneal stroma faster compared to all other species examined in the study.

Cite This Article

APA
Zibura AE, Cullen MA, Rutledge H, Lassalle L, Salmon JH, Gilger BC, Westermeyer HD. (2020). Optimizing corneal riboflavin administration in ex vivo horse, dog, rabbit, and pig samples for use in corneal collagen cross-linking. Vet Ophthalmol, 23(5), 840-848. https://doi.org/10.1111/vop.12807

Publication

Veterinary ophthalmology
ISSN: 1463-5224
NlmUniqueID: 100887377
Country: England
Language: English
Volume: 23
Issue: 5
Pages: 840-848

Researcher Affiliations

Zibura, Ashley E
  • Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
Cullen, Megan A
  • Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
Rutledge, Haley
  • Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
Lassalle, Laura
  • Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
Salmon, Jacklyn H
  • Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
Gilger, Brian C
  • Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
Westermeyer, Hans D
  • Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.

MeSH Terms

  • Animals
  • Collagen / drug effects
  • Cornea / drug effects
  • Dogs
  • Horses
  • Injections / veterinary
  • Iontophoresis / veterinary
  • Ophthalmic Solutions / administration & dosage
  • Ophthalmic Solutions / pharmacology
  • Photosensitizing Agents / administration & dosage
  • Photosensitizing Agents / pharmacology
  • Rabbits
  • Riboflavin / administration & dosage
  • Riboflavin / pharmacology
  • Species Specificity
  • Swine

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