ObjectiveTo investigate the anti-inflammatory effect and mechanism of Danggui Shaoyaosan （DSS） in ameliorating vascular dementia （VaD）.MethodsSeventy 8-week-old C57BL/6J male mice were randomized into 7 groups： control， model， sham， positive control （donepezil， 10 mg·kg^-1）， and low-， medium-， and high-dose （12， 24， 36 g·kg^-1， respectively） DSS groups （n=10）. After drug administration， behavioral tests and cerebral blood flow detection were carried out. Enzyme-linked immunosorbent assay was used to assess the levels of interferon （IFN）-α， tumor necrosis factor （TNF）-α， interleukin （IL）-6， and CXC motif chemokine ligand 10 （CXCL10） in the brain tissue. Hematoxylin-eosin staining was employed to observe the changes in hippocampal morphology. Transcriptomics was used to predict the potential signaling mechanisms of DSS in ameliorating neuroinflammation， and Western blot and Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） were conducted to verify the expression changes of related genes.ResultsCompared with the control group and the sham group， the model group showed deceases in recognition index in the new object recognition test， movement distance and time in the target quadrant， and number of crossings in the Morris water maze test （P<0.01）. In addition， the model group showed slow cerebral blood flow and down-regulated protein levels of postsynaptic density protein 95 （PSD95） and occludin （P<0.05， P<0.01）， and there was no significant difference between the control group and the sham group. Compared with the model group， the DSS at each dose increased the new object recognition index， the distance and time in the target quadrant， the number of crossings， and cerebral blood flow （P<0.05， P<0.01）. In terms of brain tissue injury-related protein expression and inflammatory factor content， the medium-dose DSS group had the best effect， with higher protein levels of PSD95 and occludin （P<0.05） and lower levels of IFN-α， TNF-α， and IL-6 （P<0.01） than the model group. The hippocampus of model mice showed pathological manifestations such as cell loss and disarrangement， which were alleviated after administration of DSS at each dose. Transcriptomic results indicated that interferon regulatory factor 7 （IRF7）， signal transducer and activator of transcription 3 （STAT3）， and bone marrow stromal cell antigen 2 （BST2） were differentially expressed genes （down-regulated） in control group and medium-dose DSS group compared with the model group. The KEGG pathway enrichment analysis showed that RIG-Ⅰ-like receptor signaling pathway， Toll-like receptor signaling pathway， cytosolic DNA-sensing pathway， and downstream stimulator of interferon genes （STING） were both upstream signaling pathways affecting IFN expression. Real-time PCR results indicated that the mRNA levels of cyclic good manufacturing practice（GMP）-adenosine monophosphate（AMP） synthase （cGAS）， STING， IRF7， STAT3， and BST2 in the model group were higher than those in the sham group （P<0.05， P<0.01）. The mRNA levels of all the genes in the medium-dose DSS group were down-regulated compared with those in the model group after administration （P<0.05， P<0.01）. Western blot results indicated that the relative expression levels of cGAS， STING， p-IRF7， p-STAT3， and BST2 in the model group were higher than those in the sham group （P<0.05， P<0.01）. The protein levels of cGAS， STING， p-IRF7， p-STAT3， and BST2 in the medium-dose DSS group were decreased compared with those in the model group （P<0.05， P<0.01）.ConclusionDSS ameliorates cognitive impairment in the VaD model mice by inhibiting the cGAS-STING/IRF7/STAT3-mediated neuroinflammation.

Danggui Shaoyaosan;neuroinflammation;vascular dementia;cyclic good manufacturing practice（GMP）-adenosine monophosphate（AMP） synthase （cGAS）-stimulator of interferon genes （STING）