Abstract
Purpose :
Numerous diseases detrimentally affect corneal nerves. Corneal nerve dysfunction has been linked to dry eye syndrome onset, neurotrophic keratopathy, and other diseases. The morphology and histology of corneal nerves in health and disease has been extensively studied. However, studies of corneal nerve function have been limited (e.g., electrical recordings of ciliary nerves or calcium reporter dyes in ex vivo corneas). Here, we demonstrate functional imaging of corneal nerves over time, as well as stimulus-response.
Methods :
We made a cre-lox mouse line expressing GCaMP6f against the Nestin promoter for expression in corneal nerves. We imaged corneas in vivo (mice under isoflurane) with a custom confocal imaging system and an air objective. We applied drops of KCl solution (0.3 M) and tetracaine (0.5%) to the cornea while imaging.
Results :
Fig. 1 shows a demonstration of basal corneal nerve signaling in the same cornea over the course of a month. This demonstrates how functional imaging might be used to study nerve activity changes in response to ocular surgeries or pharmaceutical treatments. Fig. 2 shows a demonstration of in vivo calcium imaging where corneal nerves respond to a stimulus. Repeated stimulus and response characterization is one way that the response of corneal nerves could be characterized over time.
Conclusions :
The in vivo demonstration of longitudinal imaging and stimulus-response builds upon previous work to develop a model system to study how corneal nerve responses change over time. This will facilitate better studies and understanding of factors that could slow the development of neuropathies. It may also help in the development and testing of new clinical interventions and therapies.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.