Application of non-invasive transcranial photobiomodulation in ischemic stroke: Mechanisms and current insights

Ischemic stroke (IS), comprising 65.3% of the 11.9 million new stroke cases worldwide in 2021, is a leading cause of disability and mortality due to cerebral vascular occlusion and subsequent ischemia. The increasing prevalence, particularly in aging populations such as China, underscores the urgent need for novel therapeutic strategies. Conventional treatments, including thrombolysis and surgery, are constrained by narrow therapeutic windows and risks such as hemorrhage. Transcranial photobiomodulation (tPBM), a non-invasive technique utilizing red or near-infrared light (630-1300 nm), has emerged as a promising intervention for IS. This review synthesizes the pathological features of IS, including blood-brain barrier disruption, oxidative stress, and neuroinflammation, and elucidates the molecular mechanisms of tPBM, such as enhanced mitochondrial function, increased cerebral blood flow, and upregulation of neurotrophic factors. Preclinical and clinical evidence demonstrate tPBM's potential to mitigate neuronal damage and promote recovery across acute, subacute, and chronic phases of IS. By evaluating current applications, this study aims to provide a theoretical foundation for optimizing treatment parameters, enhancing clinical outcomes, and guiding future rehabilitation strategies for patients with stroke.