Mechanism of Tongqiao Huashuan decoction regulating neuroinflammation and its effect on intestinal flora in vascular dementia rats

To investigate molecular changes associated with the protective effect of Tongqiao Huashuan Decoction (THD) in vascular dementia (VD), focusing on the NF‑κB‑related inflammatory response, and to observe its influence on intestinal flora. The components of THD were identified using Liquid chromatography‑quadrupole time‑of‑flight tandem mass spectrometry (LC‑Q‑TOF‑MS/MS) with electrospray ionization in positive/negative modes, a methanol‑0.1% formic acid gradient mobile phase, and a C18 column (1.7 μm, 2.1 × 100 mm). Sprague‑Dawley rats were divided into four groups: Sham, VD, VD + TCM (THD), and VD+Donepezil (donepezil hydrochloride). Spatial learning and memory were assessed using the Morris Water Maze. Transmission electron microscopy (TEM) analyzed the ultrastructure of hippocampal CA1 neurons. Enzyme‑linked immunosorbent assay (ELISA) detected interleukin‑1β (IL‑1β), tumor necrosis factor‑α (TNF‑α), macrophage inflammatory protein‑2 (MIP‑2), and IL‑6 in the hippocampus and serum. Immunohistochemistry (IHC) and Western blotting (WB) measured the expression of sirtuin 1 (SIRT1), NF‑κB, caspase‑1, and NOD‑like receptor protein 3 (NLRP3). Fecal flora was analyzed via 16S rRNA sequencing. LC‑Q‑TOF‑MS/MS detected 998 chemical constituents in THD extract. Among them, 24 high‑signal‑intensity constituents with mass‑spectrometry response values > 100 000 were tentatively annotated based on exact‑mass and MS/MS fragmentation matching against public databases and published literature. Compared with the Sham group, VD rats exhibited longer escape latency, hippocampal neuronal damage, elevated proinflammatory factors, upregulated caspase‑1/NLRP3/NF‑κB, and downregulated SIRT1/IκBα. THD treatment reversed these VD‑induced pathological abnormalities. In addition, THD restored intestinal flora dysbiosis observed in VD model rats. THD ameliorates VD‑related cognitive dysfunction, accompanied by altered expression of SIRT1/IκBα/NF‑κB‑related proteins and reduced pro‑inflammatory cytokines. Meanwhile, THD can restore disturbed gut microbiota in VD rats. Changes in the SIRT1/IκBα/NF‑κB signaling cascade are therefore associated with THD‑mediated protective outcomes.