Mechanistic approaches to the light-induced neural cell differentiation: Photobiomodulation vs Low-Dose Photodynamic Therapy

Abstract

BackgroundNeurodegenerative diseases are the result of irreversible damage in the neuronal cells by effecting vital functions temporarily or even permanently. The use of light for the treatment of these diseases is an emerging promising innovative method. Photobiomodulation (PBM) and Photodynamic Therapy (PDT) are the modalities that have a wide range of use in medicine and have opposite purposes, biostimulation and cell death respectively. MethodsIn this study, we aimed to compare these two modalities (PDT and PBM) at low-level intensities and create a stimulatory effect on the differentiation of PC12 cells. Three different energy densities (1, 3, and 5 J/cm2) were used in PBM and Chlorin e6-mediated PDT applications upon irradiation with 655-nm laser light. The light-induced differentiation profile of PC12 cells was analyzed by morphological examinations, qRT-PCR, cell viability assay, and some mechanistic approaches such as; the analysis of intracellular ROS production, NO release, and mitochondrial membrane potential change. ResultsIt has been observed that both of these modalities were successful at neural cell differentiation. PBM at 1 J/cm2 and low-dose PDT at 3 J/cm2 energy densities provided the best differentiation profiles which were proved by the over-expressions of SYN-1 and GAP43 genes. It was also observed that intracellular ROS production and NO release had pivotal roles in these mechanisms with more cell differentiation obtained especially in low-dose PDT application. ConclusionIt can be concluded that light-induced mechanisms with properly optimized light parameters have the capacity for neural cell regeneration and thus, can be a successful treatment for incurable neurodegenerative diseases.