Photobiomodulation in stroke prevention and treatment: neuroprotective mechanisms and therapeutic challenges

Stroke remains a leading cause of disability globally, resulting from sudden interruptions in blood flow to the brain. While acute treatments have been a primary focus, there is increasing interest in the potential of photobiomodulation (PBM) therapy for both stroke prevention and rehabilitation. PBM harnesses specific wavelengths of light to stimulate biological processes that can protect neural tissue and promote recovery. Recent evidence suggests that PBM therapy can lead to significant improvements in motor function for individuals experiencing post-stroke hemiparesis, especially when combined with treatments targeting both the brain and skeletal muscles. This review explores the mechanisms underlying PBM therapy, emphasizing the role of key chromophores, such as cytochrome c oxidase and calcium ion channels. It also highlights the therapeutic effects of red and near-infrared light, while considering water as a crucial chromophore that may enhance treatment efficacy. The review addresses challenges related to light penetration during various stages of stroke and underscores the importance of optimizing treatment parameters, including the use of multi-site irradiation and advanced delivery systems involving nanoparticles. By consolidating the current understanding of PBM therapy, this review aims to illustrate its promise as a non-invasive approach for stroke prevention and rehabilitation. It advocates for the development of standardized clinical protocols and personalized PBM strategies that incorporate different wavelengths and combination therapies to improve treatment outcomes. Ultimately, this review emphasizes the potential of PBM therapy to address the complex challenges posed by stroke and advance clinical practice.