RESUMO
OBJECTIVE To investigate the improvement effects and mechanism of scutellarin （Scu） on neuroinflammation in rats with traumatic brain injury （TBI）. METHODS The modified Feeney method was applied to construct TBI rat model. The rats were randomly grouped into TBI group，Scu low-dose group （40 mg/kg），Scu high-dose group （80 mg/kg），cyclic guanylate- adenylate synthase （cGAS） inhibitor group （cGAS inhibitor RU.521，450 μg/kg），with 24 rats in each group. Other 24 rats were included in the sham operation group. The modified neurological deficit score （mNSS） method was applied to assess the neurological function of rats； the brain water content of rats was measured by dry/wet specific gravity method； hematoxylin-eosin and TdT-mediated dUTP nick-end labeling staining were applied to observe the pathological changes and apoptosis of brain tissue in rats； the levels of interferon-β （IFN-β），CXC chemokine ligand-10 （CXCL10），tumor necrosis factor-α （TNF-α） and interleukin-6 （IL-6） in rat brain tissue were detected by enzyme-linked immunosorbent assay； Western blot method was applied to detect the expression of cGAS/interferon gene stimulating protein （STING） signal pathway-related proteins in brain tissue of rats. RESULTS Compared with the sham operation group，the mNSS，brain water content，apoptosis rate，the contents of IFN-β，CXCL10，TNF-α and IL-6，and the relative expressions of cGAS and STING proteins in TBI group increased significantly （P＜0.05）； there were edema，bleeding and pathological damage to neurons in the brain tissue. Compared with TBI group，the above indicators and pathological changes of rats in administration groups were improved significantly （P＜0.05），and the effect of Scu was in a dose- dependent manner （P＜0.05）； however，there was no statistically obvious difference in the above indicators between the Scu high- dose group and the cGAS inhibitor group （P＞0.05）. CONCLUSIONS Scu may alleviate neuroinflammation，reduce brain tissue damage and apoptosis，and promote the recovery of neural function in TBI rats by inhibiting the activation of cGAS/STING signaling pathway.