Fibrinogen-Driven NLRP3 Inflammasome: A Novel Therapeutic Target for Tong-Qiao-Huo-Xue Decoction in Ischemic Stroke.

Background: Plasma fibrinogen (FIB) levels exhibit a significant elevation during the acute phase of ischemic stroke (IS), and their dynamic fluctuations serve as important biomarkers for stroke onset, disease progression, and long-term prognosis. Tong-Qiao-Huo-Xue Decoction (TQHXD) is highly effective in treating blood stasis syndromes affecting the head and face. Nevertheless, the association between TQHXD and FIB in the underlying mechanism of treating IS warrants further investigation. Methods: Proteomics analysis predicted the potential therapeutic targets of TQHXD for IS. An in vivo model of middle cerebral artery occlusion followed by reperfusion (MCAO/R) was created in mice. To explore the interaction between FIB and NLRP3, as well as to verify the particular healing outcomes of TQHXD. Results: An increased blood-brain barrier (BBB) permeability was observed after MCAO/R, accompanied by substantial accumulation of FIB in the brain. In vivo experiments demonstrated that FIB triggered the activation of the NLRP3 inflammasome in microglia. Proteomic analysis revealed a significant increase in FIB levels following model induction, which were markedly reduced after treatment with TQHXD; KEGG pathway enrichment analysis indicated that these changes were primarily associated with the NOD-like receptor signaling pathway. Laser speckle contrast imaging showed that TQHXD treatment significantly improved cerebral blood flow and attenuated brain injury in mice. Fluorescence imaging, ELISA, and Western blotting results collectively demonstrated that TQHXD effectively reduced FIB accumulation and suppressed NLRP3 inflammasome activation. MD and pull-down experiments further demonstrated a strong interaction strength between FIB and NLRP3. Conclusions: FIB accumulates in the ischemic penumbra following CIRI, while TQHXD can effectively down-regulate FIB expression and inhibit NLRP3 inflammasome activation to mitigate CIRI. These findings provide a novel theoretical foundation and treatment direction for stroke management in clinical settings.