Intranasal administration of geniposide-baicalin treats ischemic stroke reperfusion conjugated with pneumonia by inhibiting HMGB1-mediated pyroptosis via NLRP3/Caspase-1/GSDMD pathway

PURPOSE: Elucidation of the optimal ratio and mechanism of action of geniposide (GE)-baicalin (BA) intranasal administration for the treatment of ischemic stroke reperfusion conjugated with pneumonia (ISR-PN). METHODS: We established both in vivo and in vitro models of ISR-PN. Using CCK-8 assay, enzyme-linked immunosorbent assay (ELISA), hematoxylin-eosin (H&E) staining, Nissl staining, whole-body volumetric profiling (WBP), modified neurological severity scoring (mNSS), and tissue edema assessment, we screened for the most effective proportion of intranasal administration of GE-BA treatment for ISR-PN. Subsequently, through tissue edema evaluation, H&E staining, Nissl staining, ELISA, WBP, mNSS, open field test, corner test, cylinder test, and laser speckle contrast imaging, we explored the key pro-inflammatory factors involved in ISR-PN. Finally, using western blotting, immunohistochemistry, immunofluorescence, quantitative real-time PCR, transmission electron microscopy, scanning electron microscopy, and flow cytometry, we investigated the mechanism of action of GE-BA in treating ISR-PN. RESULTS: The most effective ratio of GE-BA for treating ISR-PN via intranasal administration is 1:1. Specific inhibition of HMGB1 significantly improves brain and lung damage, as well as neurological and pulmonary dysfunction caused by ISR-PN. GE-BA effectively suppresses cell pyroptosis activated by high mobility group box-1 protein (HMGB1) by inhibiting the NOD-like receptor protein 3 (NLRP3)/Caspase-1/gasdermin D (GSDMD) pathway. CONCLUSION: These findings suggest that intranasal administration of GE-BA treats ISR-PN by inhibiting HMGB1-mediated pyroptosis through the NLRP3/Caspase-1/GSDMD pathway.