Corneal Neuro-Regenerative Effect of Transcutaneous Electrical Stimulation in Rabbit Lamellar Keratectomy Model

This study aimed to evaluate the effect of transcutaneous electrical stimulation (TES) on corneal nerve regeneration in rabbits injured from superficial lamellar keratectomy (SLK).

New Zealand White rabbits were used in this experimental study. To induce corneal nerve damage, SLK was performed using a 7.0-mm trephine. TES was applied for 28 days after the corneal nerve injury. Corneal sensitivity, Western blotting, real-time polymerase chain reaction (PCR), and immunofluorescence were performed to observe changes in the corneal tissue.

In the 2-Hz and 20-Hz electrical stimulation groups, the degree of corneal wound healing increased by more than 10% compared to the control group, but no significant difference was observed. Conversely, the electrical stimulation (2-Hz or 20-Hz) group showed significantly increased corneal sensitivity compared to the control group. Western blot analysis revealed that small proline-rich protein 1A (SPRR1a), a regeneration-associated protein was significantly increased in the 2-Hz group on days 1 and 7 compared to that in the other groups. Once again, nerve regeneration in the 2-Hz group was supported by the results of PCR, in which a significant increase in the nerve growth factor (NGF) on day 1 was observed compared with the other groups. Moreover, immunofluorescence after 28 days of electrical stimulation showed significant nerve regeneration in the 2-Hz group.

TES promoted corneal nerve regeneration in rabbit SLK model. The application of electrical stimulation of 2-Hz frequency was more effective than the 20-Hz frequency, showing potential clinical applications for corneal diseases.

This study shows how application of TES to the eyes that exhibit corneal nerve damage can improve corneal nerve regeneration examined by histologic analysis.