G Protein-coupled Receptors and Proopiomelanocortin Expression After Light Emitting Diode Irradiation in Diabetic Wound Healin.

OBJECTIVE: The purpose of this study is to investigate whether light-emitting diode (LED) light at different wavelengths can improve wound healing in both diabetic and normal fibroblasts.

MATERIALS AND METHODS: Both diabetic and normal fibroblast cell lines were cultured and artificial wounds were created on the cultured cells in petri dishes as a streak line with pipette tips. Then, both cells were separately irradiated with 635 nm (red), 520 nm (green), and 465 nm (blue) LED lights at 0.67 J/cm² for 10 minutes. Immediately after LED irradiation, messenger ribonucleic acid samples of each cell line were isolated for microarray analysis.

RESULTS: The investigator found that G protein-coupled receptors (GPR) class A, a rhodopsin-like structure gene, were significantly upregulated in all treated groups by transferring the signal to proopiomelanocortin (POMC) genes in diabetic cells. In addition, for normal cell groups, the expression of other genes relevant to viral defense responses markedly increased. However, in diabetic cells, genes relating to acute inflammatory response and mitotic cell cycle were highly expressed. The investigator also found that diabetic cells responded significantly better to wound healing attempts than normal cells because inflammatory response, cell migration, cell proliferation, cell adhesion, and regulation of mitosis pathways could be instantly activated by red and green LED lights.

CONCLUSIONS: These lights activate the expression of GPR class A gene, which receives photons and transfers this signal to other downstream pathways inside the cell, specifically to the POMC gene, which will recover the wound-healing process to the normal stage.