Abstract
Purpose :
The cornea is typically transparent to most wavelengths of light. Following dissection and organotypic culture, the cornea begins to express the photoreceptor, Opsin 5 (Opn5) which absorbs short-wavelength light. This confers a light sensitivity to the cornea, particularly to wavelengths in the UVA to violet range. These cells are found primarily in the epithelial layer and co-stain with known epithelial cell markers. We wished to replicate ex vivo observations of photorecepor induction in vivo using a cornea wounding model.
Methods :
Mice which express a fluorescent reporter for Opn5 expression (Opn5Cre; Ai14) were anesthetized and given cornea epithelial debridement using an algerbrush. Cells of these mice will produce red fluorescent protein (RFP) when Opn5 is transcriptionally active. Mice were between 1 and 6 months of age and were of both sexes. Three mice were euthanized and corneas collected at 0, 6, 12, 24, and 48 hours post-surgery. Observed fluorescent cells were used as a representation of OPN5 positive cells. The untreated eyes were used as a control group.
Results :
OPN5 cells were observed in the epithelial layer of debrided corneas in a manner consistent to what we previously observed ex vivo. Opn5-positive cells were induced by 6 hours after debridement and were no longer present by 48 hours. The peak number of cells was observed at 12 hours post-surgery. This is a much faster induction than we had measured ex vivo, in which the OPN5 cells begin to appear approximately 18 to 24 hours post-dissection. The induced cells were found close to the healing perimeter, but also throughout the epithelium. No induction of Opn5-positive cells was observed in the untreated corneas.
Conclusions :
A photoreceptive system is induced in the mouse cornea after epithelial debridement. These photoreceptive cells express the opsin OPN5 and confer direct light sensitivity to the cornea both in vivo and ex vivo. In the future we hope to assess any role these cells play in the healing process.
This is a 2021 ARVO Annual Meeting abstract.