Application of Photobiomodulation Therapy by LED Using a Combined Red and Near-infrared Light Spectrum Improves the Vascular Function of the Radial Artery in Vitro

LED photobiomodulation therapy (PBMT) is widely recognized for its beneficial effects in several clinical conditions; however, its potential in modulating vascular function is not yet fully established. Objective: This study aimed to evaluate the application of PBMT by LED (light-emittion diode) using a combined red and near-infrared light spectrum, with a focus on improving the vascular function of the radial artery in vitro. Methodology: A total of 30 radial artery segments were studied and divided into three groups of 10 segments: the PBMT LED group combined with red and infrared light (R + IR), the red light (R) group, and the infrared light (IR) group. Prior to light irradiation at wavelengths of 650 nm and 940 nm, vascular function in these segments was pharmacologically inhibited using L-NAME. The drugs phenylephrine, acetylcholine, and sodium nitroprusside were used to determine if irradiation could restore the inhibited vascular functions. Superoxide anion levels, an important reactive oxygen specie (ROS), were measured using a chemiluminescence assay with lucigenin. The bioavailability of nitric oxide was evaluated using a Griess Reagent Kit assay, while nitric oxide production was assessed through the DAF fluorescence assay. The vascular inflammation was determined by the Intercellular Adhesion Molecule 1 (ICAM-1) expression.