Revisiting the Emerging Role of Light-Based Therapies in the Management of Spinal Cord Injuries

The surge in spinal cord injuries (SCI) attracted many neurobiologists to explore the underlying complex pathophysiology and to offer better therapeutic outcomes. The multimodal approaches to therapy in SCI have proven to be effective but to a limited extent. The clinical basics involve invasive procedures and limited therapeutic interventions, and most preclinical studies and formulations are yet to be translated due to numerous factors. In recent years, photobiomodulation therapy (PBMT) has found many applications in various medical fields. In most PBMT, studies on SCI have employed laser sources in experimental animal models as a non-invasive source. PBMT has been applied in numerous facets of SCI pathophysiology, especially attenuation of neuroinflammatory cascades, enhanced neuronal regeneration, reduced apoptosis and gliosis, and increased behavioral recovery within a short span. Although PBMT is specific in modulating mitochondrial bioenergetics, innumerous molecular pathways such as JAK-STAT, PI3K-AKT, NF-κB, MAPK, JNK/TLR/MYD88, ERK/CREB, TGF-β/SMAD, GSK3β-AKT-β-catenin, and AMPK/PGC-1α/TFAM signaling pathways have been or are yet to be exploited. PMBT has been effective not only in cell-specific actions in SCI such as astrocyte activation or microglial polarization or alterations in neuronal pathology but also modulated overall pathobiology in SCI animals such as rapid behavioral recovery. The goal of this review is to summarize research that has used PBMT for various models of SCI in different animals, including clarifying its mechanisms and prospective molecular pathways that may be utilized for better therapeutic outcomes.