Exosomes as regenerative therapeutics for spinal cord injury: mechanisms and clinical prospects

Exosomes are nanometer-scale extracellular vesicles secreted by cells with a diameter of approximately 30-100 nanometers. Serving as essential messengers for intercellular communication, they play significant roles in both physiological and pathological processes. Their low immunogenicity, excellent tissue penetrability, and high biocompatibility have positioned them as a research focus for disease diagnostic biomarkers and drug delivery vehicles. Spinal cord injury (SCI) is a severe traumatic disorder of the nervous system, often leading to neuronal death, axonal disruption, glial scar formation, and dysregulated inflammatory responses, ultimately resulting in irreversible sensory and motor dysfunction. This review systematically elucidates the pivotal roles of exosomes derived from various cell sources in the repair of SCI. It focuses on how these exosomes target key cellular components including neurons, glial cells, vascular endothelial cells, and immune cells. This interaction modulates core pathological processes such as neuroinflammation, glial scar formation, axonal regeneration, angiogenesis, and apoptosis. By synthesizing current evidence, we aim to unravel the complex regulatory networks mediated by exosomes as intercellular signaling hubs within the SCI microenvironment. Furthermore, this review provides a theoretical foundation for their future development as novel diagnostic tools, regenerative therapeutic vectors, and targeted intervention strategies for SCI.