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. 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. A total of 40 radial artery segments were studied and divided into Four groups of 10 segments, including the control (C), red (R), infrared (IR), and combined red + infrared (R + IR). 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. The vascular inflammation was determined by the Intercellular Adhesion Molecule 1 (ICAM-1) expression. The results indicate that combined PBMT improved vascular function compared to PBMT with isolated light spectra, promoting greater vascular relaxation by increasing nitric oxide by increasing nitric oxide bioavailability and decreasing the superoxide anion production. Additionally, the combined light spectrum and the red spectrum decreased the ICAM-1 expression. Combined spectrum LED photobiomodulation therapy improves vascular function by promoting vasodilation, reducing reactive oxygen species (ROS) production, and attenuating inflammatory responses.