Astragaloside IV-preconditioned neural stem cell transplantation promotes neurogenesis and functional recovery via the miR-199a-5p/Caveolin-1 pathway in a rat model of ischemic stroke

Neuronal loss following ischemic stroke (IS) is a major cause of long-term neurological dysfunction. Neural stem cell (NSC) transplantation holds great potential for neural tissue repair, but exogenous NSCs often over-differentiate into astrocytes, resulting in glial scar formation and poor neuronal maturation, which limits clinical application. Astragaloside IV (AS-IV), a plant-derived monomer, has been shown to regulate the proliferation, migration, and differentiation of endogenous NSCs. This study investigated whether AS-IV preconditioning could promote the neurogenesis of transplanted NSCs and improve functional recovery after IS. Primary NSCs were cultured and exposed to various concentrations of AS-IV, and 100 μM was selected for further use. A rat model of middle cerebral artery occlusion/reperfusion (MCAO/R) was established, and AS-IV-preconditioned or untreated EGFP-labeled NSCs were transplanted into the striatum. Brain injury was assessed histologically. Neurological recovery was evaluated using the modified Neurological Severity Score, grip strength, adhesive removal, and Morris water maze tests. Immunofluorescence staining was used to assess graft survival, differentiation fate, synapse formation, and glial scar area. In vitro experiments explored the involvement of the miR-199a-5p/Caveolin-1 signaling pathway. AS-IV preconditioning significantly improved the survival and neuronal differentiation of grafted NSCs, reduced astrocytic lineage commitment and glial scar formation, and enhanced synaptic reconstruction. These effects were associated with improved sensorimotor and cognitive function. In conclusion, AS-IV pretreatment of NSCs promoted neuronal lineage commitment, inhibited glial scarring, and facilitated functional recovery after ischemic stroke. Targeting the miR-199a-5p/Caveolin-1 axis may offer a novel strategy for optimizing NSC-based therapy in stroke.