Astrocyte-derived exosomes in cognitive recovery: A comparative assessment of neurobehavioral, molecular, and electrophysiological dimensions.
📄 Abstract
Despite the growing interest in cell- and exosome-based therapies for neurological diseases including Alzheimer's disease (AD), there is still a gap in the investigation of more effective treatments in terms of efficacy, safety, and durability of effect. This study aimed to compare the therapeutic potential of astrocyte cells and their derived exosomes (AS-Exos) in restoring cognitive function in a mouse model of AD. AD model was induced by bilateral electrical lesioning of the nucleus basalis of Meynert (NBM). Astrocytes were isolated from neonatal rat brains, and AS-Exos were harvested from astrocyte-conditioned media using an AnaCell extraction kit. Seven days after lesion induction, astrocytes and AS-Exos were stereotaxically injected into the NBM. Four weeks later, behavioral assessments (passive avoidance and locomotor activity), electrophysiological recordings (EEG), and biochemical measurements of hippocampal brain-derived neurotrophic factor (BDNF) and acetylcholine (ACh) levels were performed. AS-Exos were confirmed as cup-shaped vesicles (30-150 nm) expressing the exosomal surface markers CD9, CD63, and CD81. NBM lesions significantly reduced step-through latency (STL), hippocampal BDNF and ACh levels, and disrupted EEG oscillatory patterns. Treatment with AS-Exos markedly improved STL and produced greater increases in hippocampal BDNF and ACh levels compared with AD and AD+saline groups. EEG analysis also revealed enhanced beta, alpha, and gamma power, with the most robust normalization observed in the AS-Exos group. AS-Exos demonstrated superior biochemical and electrophysiological benefits compared with astrocyte transplantation and provided equal or greater improvement in behavioral outcomes. These findings highlight AS-Exos as a promising cell-free therapeutic strategy for alleviating cognitive deficits associated with AD.