Abstract
Purpose :
We evaluated the neurochemical characteristics of regenerating and regenerated corneal nerves after excimer laser keratectomy in rats.
Methods :
Following fast blue dye was applied on corneas for retrograde nerve tracing, phototherapeutic keratectomy (PTK) was performed on unilateral eyes of 8-week old male SD rats (n = 39) at the age of 8 weeks, and the corneas and ipsilateral trigeminal ganglions were obtained at 3 days, 1 week, 1 and 2 month after intervention. Immunohistochemistry, ELISA, and RT-PCR analysis were performed for TAC1, CGRP, P2RX3, IB4, TrkA, GFRA1, NGF, and GDNF, and GAP43.
Results :
Immunohistochemical analysis revealed that regenerating corneal axons and their trigeminal ganglions showed increased density of TAC1 (substance P) and GAP43-immunoreactivity (IR) nerves, whereas regenerated nerves and naïve nerves in controls did not. The mRNA expression of TAC1, TrkA and GAP43 were upregulated in trigeminal ganglions at 3 days, 1 week, and not at 1 and 2 months. ELISA showed that TAC1 and NGF concentration in corneas were significantly elevated at 3 days and 1 week.
Conclusions :
Regenerating corneal nerves showed the neurochemical characteristics of NGF-responsive peptidergic sensory nerve with abnormal structures. Further studies are needed to evaluate the molecular and electrophysiological property of regenerating corneal nerves.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.