Effect of Photobiomodulation on Wound Healing of the Corneal Epithelium through Rho-GTPase

Abstract

Background and ObjectivesIn recent years, photobiomodulation (PBM) using low-level light has been applied to diverse clinical approaches because of its potential to elevate the cell metabolism or regulate various signaling pathways. This study evaluated the possibility of a short term effect of PBM on the wound healing of corneal epithelial cells. Rapid healing of the corneal epithelium and the return of an intact basement membrane can restore the eye's normal mechanical barriers. The migration, proliferation, attachment, and cytoskeletal rearrangement play a critical role in the wound healing process of the corneal epithelium. Materials and MethodsTo determine which wavelength was most effective on corneal epithelium wound healing, light emitting diode (LED) arrays with wavelengths of 470, 530, 660, 740, and 850 nm were used. The proliferative effect was assessed using a MTT assay, cell cycle assay, and BrdU immunofluorescence (IF) staining, and the motility effect was examined using a wound healing assay after PBM. The cytoskeletal rearrangement effect of PBM was also evaluated by Western blot analysis and IF staining.Results PBM had no effect on cell proliferation; the cell cycle portion and BrdU were not changed after the PBM treatment, whereas cell survival was decreased at 470 nm. On the other hand, PBM at wavelengths greater than 660 nm affected migration. In particular, 740 nm was the most effective. The expression of Rho A and Rho C increased after PBM at wavelengths greater than 660 nm. The levels of cdc42 and mTORC2 expression were similar. ConclusionThis study showed that PBM could increase the corneal epithelial cell migration capacity without cell proliferation in a short time via the activation of a part of Rho-GTPase pathways without the effect of the upstream signals. These findings may be used for the future development of PBM-based therapy for acute ocular surface diseases. Key words

Effects of Low-level Light Therapy at 740 nm on Dry Eye Disease In Vivo

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