Effects of 660‐nm and 780‐nm Laser Therapy on ST88‐14 Schwann Cells

Abstract The aim of the present study was to evaluate the comparative effects of red (660‐nm) and near‐infrared (780‐nm) low‐level laser therapy (LLLT) on viability, mitochondrial activity, morphology and gene expression of growth factors on Schwann cells (SC). ST88‐14 cells were grown in RPMI 1640 with 10 mM of HEPES, 2 mM of glutamine, 10% fetal bovine serum and 1% antibiotic‐antimycotic solution at 37°C in humidified atmosphere of 5% CO 2 . Cells were detached with trypsin and centrifugated at 231 g for 5 min at 10°C, and the pellet (8 × 10 4 cells/tube) was irradiated at the bottom of 50 ml polypropylene tube with a Twin‐Laser system (660 and 780 nm, 40 mW, 1 mW cm −2 , 3.2 and 6.4 J, 80 and 160 J cm −2 with 80 and 160 s). After 1, 3 and 7 days, the analysis was performed. After irradiation, the SC increase mitochondrial activity, gene expression of the neural growth factors NGF and BDNF, and cell migration and increase the G2/M cells. SC showed neuronal morphology, normal F‐actin cytoskeleton organization and positive labeling for S100. PBM increased metabolic activity, mitosis and gene expression when irradiated with red and infrared LLLT. An increase in cell migration was obtained when irradiated with infrared LLLT.