670nm Photobiomodulation Modulates Bioenergetics And Oxidative Stress, Decreasing Inflammatory Mediator Production In An In Vitro Model Of Diabetic Retinopathy

Abstract

Diabetic retinopathy (DR), the most common complication of diabetes mellitus, is associated with oxidative stress, nuclear factor-kB (NFkB) activation, and excess production of vascular endothelial growth factor (VEGF) and intracellular adhesion molecule-1 (ICAM-1). Current therapies are invasive, frequently ineffective, and have adverse effects. The application of far-red to near-infrared (NIR) light (630-1000nm) reduces oxidative stress and inflammation in vitro and in vivo. Thus, we hypothesize that 670nm light treatment will dimish oxidative stress preventing downstream inflammatory mechanisms associated with DR. We used an in vitro model system of rat Müller glial cells grown under normal (5 mM) or high (25 mM) glucose conditions and treated with a 670 nm light emitting diode array (LED) (4.5 J/cm2) or no light (sham) daily. We report that a single 670 nm light treatment diminished ROS production and preserved mitochondrial integrity and ATP production in this in vitro model of diabetic retinopathy. Furthermore, treatment for 3 days in culture reduced NFkB activity to levels observed in normal glucose and prevented the subsequent increase in ICAM-1. The ability of 670nm light treatment to prevent early molecular changes in this established DR model system suggests light treatment could become an early therapeutic option for DR.