The order of green and red LEDs irradiation affects the neural differentiation of human umbilical cord matrix-derived mesenchymal cells

Different wavelengths emitted from light-emitting diodes (LEDs) are known as an influential factor in proliferation and differentiation of various cell types. Since human umbilical cord matrix-derived mesenchymal cells (hUCMs) are ideal tools for human regenerative medicine clinical trials and stem cell researches, in the present study we investigated the neurogenesis effects of single and intermittent green and red LED irradiation on hUCM cells. Exposure of hUCMs to single and intermittent green (530 nm, 1.59 J/cm²) and red (630 nm, 0.318 J/cm²) lights significantly increased the expression of specific genes including nestin, β-tubulin III and Olig2. Additionally, immunocytochemical analysis confirmed the expression of specific neural-related proteins including nestin, β-tubulin III, Olig2 and GFAP. Also, alternating exposure of hUCM cells to green and red lights increased the expression of some neural markers more than either light alone. Further research are required to develop the application of LED irradiation as a useful tool for therapeutic purposes including neural repair and regeneration.