Intranasal delivery of glioblastoma exosomes-loaded injectable chitosan hydrogel promotes neurovascular unit restoration in ischemic stroke.

Abstract

The homeostasis of the Neurovascular Unit (NVU), a basic functional unit of the brain, is essential for neurological recovery. Glioblastoma-derived exosomes have been demonstrated to enhance angiogenesis under hypoxic conditions, but their reparative potential in non-tumor ischemic microenvironments remain unclear. Moreover, free Exos are limited by rapid clearance, poor lesion retention, and uncontrolled release. Herein, we prepared an injectable chitosan hydrogel loaded with A172 cell-derived Exos (H-A-Exos) for intranasal delivery and evaluated its therapeutic effects in a rat middle cerebral artery occlusion (MCAO) model. In vitro, A-Exos facilitated endothelial cell proliferation, migration, and vascular endothelial growth factor (VEGF) expression, while inhibiting NVU cell apoptosis and reducing oxidative stress and inflammatory responses. When loaded within injectable chitosan hydrogel, A-Exos exhibited enhanced retention and sustained release, resulting in improved accumulation in the ischemic infarct area following intranasal administration. Compared to the model group, H-A-Exos significantly improved behavioral recovery, as evidenced by reduced modified Neurological Severity Score (mNSS), and decreased cerebral infarct volume (13.02 ± 1.01%), showing superior efficacy to free A-Exos and Nimodipine (NMDP). Mechanistically, H-A-Exos upregulated eNOS, Bcl-2, VEGF and CD31 expression, thereby promoting vascular regeneration and NVU remodeling. Thus, these findings confirm the effective pro-angiogenic and reparative roles of A-Exos in a non-tumor ischemic microenvironment and demonstrate that intranasal H-A-Exos represents a promising therapeutic strategy for restoring NVU homeostasis and enhancing revascularization following ischemic stroke, underscoring their innovative therapeutic potential.