Oftalʹmologiâ (Jun 2019)
Experimental Model of Recurrent Corneal Erosion
Abstract
Introduction. In a number of pathological conditions accompanied by the basement membrane defects, such as chemical or thermal burns, mechanical trauma, Sjögren’s syndrome, neurotrophic keratopathy or some corneal dystrophies, in which conditions are created independent epithelialization is weakened or becomes impossible. This condition was named recurrent corneal erosion (RCE). For the experimental study of the regenerative processes and evaluation of the effectiveness of new treatments, a standardized and reproducible RCE model is needed. Several RCE models are known: chemical, bacterial. The disadvantages of such models are the labour intensity of their implementation and a relatively high cost. The proposed method makes it possible to create the necessary conditions for local inflammation and destruction of adhesive molecules using the energy of ultraviolet (UV) irradiation. In this study, an experimental RCE model in rabbits has been proposed.Purpose. To create a reproducible standardized experimental model of recurrent corneal erosion.Materials and methods. The studies were conducted in 8 chinchilla rabbits (16 eyes). After local instillation (0.5 % alkaine solution) and retrobulbar anesthesia (2 % lidocaine solution), superficial deepithelialization of the cornea was performed by mechanical removal of its epithelium with a blunt scraper; and the quality of deepithelialization was assessed by staining the surface with 2 % fluorescein solution. In the optical zone with a diameter of 4 mm, local UV irradiation of the cornea was performed with exposures of 30 and 45 minutes.Results. In case of 30-minute exposures, the epithelialization of the cornea subjected only to mechanical deepithelialization was observed since Day 3 in the form of concentric epithelial growth. On Day 14, a complete epithelialization of the cornea was observed, along with the formation of superficial newly formed vessels along the limbus. On Day 24, the vascular injection significantly decreased; and no erosion was observed. After 45-minute exposure without treatment, the regeneration occurred much slower; and a complete epithelialization had been achieved by Day 34 of the experiment, by the time the newly formed vessels grew to the epithelial defect zone. It was noted that since Day 86, the turbidity in the irradiation area persisted, as well as the inflammatory infiltrate.Conclusions. The proposed method makes it possible to reproduce RCE, in which there is an alternation of epithelialization and deepithelialization of the irradiated corneal area through 30 days of the experiment and is arrested only after the ingrowth of surface vessels into the affected area. At that, the non-irradiated cornea is epithelialized by Day 7 of the experiment.
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