Abstract
Purpose :
Corneal sensory nerves release trophic mediators that maintain and heal the corneal epithelium. In the absence of innervation, patients develop neurotrophic keratopathy (NK), characterized by corneal epithelial breakdown and progressive corneal scarring and vision loss. Corneal neurotization is a surgical procedure to reinnervate the cornea that has been shown to improve sensation in patients with NK. It remains uncertain whether donor axons reinnervating the cornea restore trophic support to the corneal epithelium. The present study investigates whether corneal neurotization prevents corneal epithelial breakdown and corneal scarring in a novel rat model of NK.
Methods :
In the present experiment, rats with NK (negative control, n = 5) were compared to rats with NK treated with corneal neurotization (treatment group, n = 10). Previously validated rat models of NK and corneal neurotization were used. Tarsorrhaphy was performed to prevent corneal injury prior to outcomes assessment. Four weeks after ablation, the tarsorrhaphy was removed in all rats exposing the denervated. Standardized digital photographs were taken daily for one week under i) normal light and ii) with a Wood’s lamp/fluorescein staining to assess corneal scarring and epithelial breakdown respectively. The area of de-epitheliazation was calculated as a percentage of the entire cornea using ImageJ. Data was further analyzed using a Fisher’s exact test or Student’s t-test.
Results :
Seven days after tarsorrhaphy removal, rats treated with corneal neurotization demonstrated significantly less corneal epithelial breakdown than untreated controls (30.1% ± 12.7 vs. 0.0 ± 0.0, p < 0.0001). All untreated rats developed progressive epithelial breakdown, while only two rats with corneal neurotization developed epithelial breakdown that healed within one week (p = 0.007). No rats with corneal neurotization developed a perforation in comparison to 80% of untreated rats (p = 0.0037). Corneal neurotization reduced corneal scarring.
Conclusions :
Corneal neurotization decreases corneal epithelial breakdown in rats with NK and prevents scarring and perforation. These results suggest that the axons reinnervating the cornea after corneal neurotization improve corneal epithelial maintenance and repair, although further research using this model is necessary to elucidate the underlying mechanisms.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.