In Vivo Serial Imaging of Regenerating Corneal Nerves after Surgical Transection in Transgenic Thy1-YFP mice

Abstract

Although corneal NFD recovers to normal levels by 8 weeks after nerve transection, the arrangement of regenerated nerves is abnormal.

Functional Properties of Sensory Nerve Terminals of the Mouse Cornea

“…Such interest extends also to the eye, and in recent years, many publications have used mice to analyze normal and pathologic ocular processes, including those affecting the sensory innervation of the corneal surface. [1][2][3] As a result of these studies, the distribution and architecture of mouse corneal sensory innervation is reasonably well known, confirming that it follows the morphologic pattern of corneal nerve branching described in other mammalian species, 4,5 although remarkable differences exist in nerve density between mice strains. 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.…”

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

“…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. In fact, we observed that corneal sensory terminals of different modality required variable times to recuperate responsiveness to their natural stimuli.…”

Corneal Neurotoxicity Due to Topical Benzalkonium Chloride

“…We have previously reported that changes in subbasal nerve pattern may occur with sequential stereofluorescence microscope imaging in thy1-YFP mice corneas, even without any intervention. 15 The deeper stromal nerve pattern and density remained constant. Therefore, we reasoned that because stromal nerves are less prone to variability in sequential measurements, changes in their pattern and density will be indicative of true neurotoxicity.…”

“…29 We, as well as others, have reported that regenerating nerves in the cornea do not follow pre-existing tracks; therefore, the appearance of new fluorescent nerve fibers in a new pattern signifies nerve regeneration. [14][15][16] We visualized two forms of stromal nerve neurotoxicity. Reversible neurotoxicity (axonopathy) was characterized by Western blot analyses of corneal lysate showed an increase in abundance of proteins associated with inflammation (IL6 and CD3) at 1 week and reduced abundance at 4 weeks.…”

“…14 We have recently described nerve regeneration events in these mice. 15,16 In the investigations reported here, we applied BAK to eyes of these mice and sequentially visualized the corneal nerves to characterize BAK-induced neurotoxicity. Furthermore, we confirmed BAK-induced neurotoxicity by molecular analyses of markers for nerve degeneration and regeneration and in cultured trigeminal ganglion cells.…”