Qixiong Zuogui-preconditioned mesenchymal stem cell-derived exosomes protect neurovascular unit in aged rats subjected to middle cerebral artery occlusion/reperfusion

BACKGROUND Neurovascular unit (NVU) dysfunction is a key pathological mechanism underlying neurological impairment in elderly patients with ischemic stroke (IS).Mesenchymal stem cell-derived exosomes (MSC-Exos) have emerged as a promising therapeutic modality for IS.Qixiong Zuogui Compound (QXZG), a traditional Chinese herbal formula with kidney-tonifying and blood-activating properties, may potentiate the protective effects of MSC-Exos in IS; however, the underlying mechanisms remain largely unexplored.AIM To investigate whether QXZG-preconditioned MSC-Exos (QXZG-Exos) promote neurological recovery by modulating the NVU in rats with D-galactose-induced aging subjected to middle cerebral artery occlusion/reperfusion (MCAO/R).METHODS High-throughput sequencing was used to compare the microRNA (miRNA) expression profiles of MSC-Exos treated with blank serum or QXZG-containing serum.Differentially expressed miRNAs were screened and subjected to bioinformatic analysis to identify key biological processes and major signaling pathways.Candidate miRNAs were further validated by reverse transcription quantitative polymerase chain reaction.In addition, rats with D-galactose-induced aging subjected to MCAO/R were used to evaluate the protective effects of QXZG-Exos on NVU integrity.Molecular biology techniques were used to comprehensively analyze the effects of QXZG-Exos on various NVU components and to assess whether they inhibit inflammatory responses and restore NVU homeostasis, potentially through modulation of the sirtuin 1 (SIRT1)/nuclear factor kappa B p65 (NF-κB p65) pathway.4 / 52 RESULTS High-throughput sequencing identified 56 differentially expressed miRNAs.Gene Ontology enrichment analysis revealed significant involvement in biological processes, including the inflammatory response, whereas Kyoto Encyclopedia of Genes and Genomes pathway analysis identified the NF-κB signaling pathway and cellular senescence as key target mechanisms.Animal experiments confirmed that QXZG-Exos improved NVU ultrastructure, enhanced neuronal nuclei expression, downregulated glial fibrillary acidic protein, and upregulated cluster of differentiation 31 and vascular endothelial growth factor A, thereby reducing neuronal damage and blood-brain barrier permeability and ultimately protecting the NVU.In addition, QXZG-Exos ameliorated neurological deficits and pathological injury and improved learning and memory after MCAO/R.Mechanistically, QXZG-Exos upregulated SIRT1 expression and suppressed NF-κB p65 and its downstream inflammatory factors by modulating the SIRT1/NF-κB pathway.CONCLUSION QXZG may modulate miRNA expression profiles in MSC-Exos, thereby improving NVU structural integrity and attenuating inflammatory injury.These effects may be associated with regulation of the SIRT1/NF-κB pathway.