Topical Mitomycin-C enhances subbasal nerve regeneration and reduces erosion frequency in the debridement wounded mouse cornea

Abstract

Corneal epithelial basement membrane dystrophies and superficial injuries caused by scratches can lead to recurrent corneal erosion syndrome (RCES). Patients and animals with reduced corneal sensory nerve innervation can also develop recurrent erosions. Multiple wild-type mouse strains will spontaneously develop recurrent corneal erosions after single 1.5 mm debridement wounds. Here we show that this wound is accompanied by an increase in corneal epithelial cell proliferation after wound closure but without a commensurate increase in corneal epithelial thickness. We investigated whether excess corneal epithelial cell proliferation contributes to erosion formation. We found that topical application of Mitomycin C (MMC), a drug used clinically to improve healing after glaucoma and refractive surgery, reduces erosion frequency, enhances subbasal axon density to levels seen in unwounded corneas, and prevents excess epithelial cell proliferation after debridement wounding. These results suggest that topically applied MMC, which successfully reduces corneal haze and scarring after PRK, may also function to enhance subbasal nerve regeneration and epithelial adhesion when used to treat RCES.

Reduced intraepithelial corneal nerve density and sensitivity accompany desiccating stress and aging in C57BL/6 mice

“…In addition, MMC treatment did not prevent the loss of axon density seen when mice are exposed to acute DS. Although experiments performed on debridement wounded mice indicate that MMC stabilizes axons by increasing adhesion between axons and ECM secreted by corneal epithelial cells (Pal-Ghosh et al, 2016), MMC treatment does not prevent axonal loss due to DS.…”

“…Fixing and staining of mouse corneas for identification of the intraepithelial nerve terminals has been described previously (Pal-Ghosh et al, 2016). Corneas were incubated with βIII tubulin (Biolegend, #801201) and/or ki67 (Abcam, # ab16667), at 4 °C.…”

“…Topical application of MMC (0.02%) is used clinically in ophthalmology during glaucoma and refractive surgical procedures to reduce scarring (Abraham et al, 2007; Santhiago et al, 2012; Shalaby et al, 2009). Using a BALB/c mouse model for recurrent epithelial erosions, we found that two topical applications of MMC (0.02%) delivered 3 and 7 days after 1.5 mm debridement wounding significantly improved resolution of erosions and increased axon density (Pal-Ghosh et al, 2016). The impact of topical MMC treatment on ICN density in dry eye disease has not been studied.…”

Functional and Morphologic Alterations in Mechanical, Polymodal, and Cold Sensory Nerve Fibers of the Cornea Following Photorefractive Keratectomy

“…These forces are transmitted to the subbasal axons and to the reassembling epithelial basement membrane, likely affecting adhesion between epithelial cells, basement membrane, and subbasal axons and thereby, the navigation of regenerating axons. 41 Considering the numerous positive and negative regulators influencing the final trajectory and elongation of axons after injury, the slow and incomplete recovery of the prelesion innervation architecture after PRK is not surprising. 42 Our study revealed that the appearance of sprouting axons within the injured area does not imply an immediate and parallel recovery of their function.…”

Functional Properties of Sensory Nerve Terminals of the Mouse Cornea

“…4 Additionally, the corneal innervation of mice has been used to explore the origin and trophic dependence of peripheral sensory nerves during prenatal development 6 and postinjury nerve regeneration in adults, 3,7,8 as well as age-dependent changes in the architecture and function of corneal nerves. 2,9 Moreover, mice have been extensively employed to define the morphologic alterations of corneal nerves caused by a number of pathologic conditions such as diabetes, 10 surgical injury, 1,11,12 herpes virus infections, 13,14 and dry eye disease. 15,16 In contrast to the ample knowledge of the anatomy of the corneal innervation in mice, its functional characteristics are still poorly defined.…”