灯盏乙素对大鼠脑缺血后小胶质细胞cGAS/STING/NLRP3信号轴的调控

Regulation of scutellarin on cGAS/STING/NLRP3 signaling axis in microglia after cerebral ischemia in rats

目的:探讨灯盏乙素对大鼠脑缺血后小胶质细胞环状GMP-AMP合成酶(cGAS)/干扰素基因刺激蛋白(STING)轴及NOD样受体热蛋白结构域相关蛋白3(NLRP3)表达的影响。方法:将36只成年雄性SD大鼠随机分为假手术组(sham)、大脑中动脉栓塞(MCAO)、MCAO+灯盏乙素干预组(MCAO+S)。开颅法制备大鼠脑缺血模型,分别用HE染色观察大鼠脑组织病理性变化,免疫荧光染色检测大鼠小胶质细胞中cGAS、STING、NLRP3表达的变化,Western Blot检测大鼠缺血后3 d脑内cGAS、STING、NLRP3蛋白表达的变化。结果:HE染色显示,灯盏乙素干预后,缺血区皮质中神经细胞数量减少、分布紊乱、细胞间隙大等病理现象较MCAO组明显改善;免疫荧光染色显示MCAO+S组中小胶质细胞的激活受到抑制,cGAS、STING、NLRP3在小胶质细胞中的表达水平下降;Western Blot结果显示,MCAO组中cGAS、STING、NLRP3表达显著增加,灯盏乙素干预后,上述指标明显下降。结论:灯盏乙素可抑制大鼠脑缺血后小胶质细胞中cGAS/STING/NLPR3的过表达,减轻小胶质细胞介导的神经炎症。

Objective:To investigate the impact of scutellarin on cyclic GMP-AMP synthase(cGAS)/stimulator of interferon genes(STING)axis and NOD-like receptor pyrin domain-associated protein 3(NLRP3)within microglia following cerebral ischemia.Methods:A rat model of cerebral ischemia was induced through craniotomy,after which 36 adult male Sprague-Dawley(SD)rats were randomly allocated into sham operation group(sham),middle cerebral artery occlusion group(MCAO)and MCAO with scutellarin group(MCAO+S)at 3d post-ischemia.Pathological alterations in the brain were assessed using hematoxylin and eosin(HE)staining.Immunofluorescence staining and Western Blot analysis were employed to examine the alterations in the expression levels of cGAS,STING and NLRP3 proteins.Results:HE staining revealed a significant improvement in the quantity and distribution of neurons,as well as a reduction in vacuole formation within the ischemic cortex in the scutellarin intervention group compared to the MCAO group.Immunofluorescence staining demonstrated suppressed microglial activation in the MCAO+S group,accompanied by reduced expression of cGAS,STING and NLRP3 in microglia.Western Blot results indicated a substantial decrease in the expression levels of cGAS,STING and NLRP3 in MCAO rats following scutellarin intervention,while these factors exhibited significant increases in the MCAO group.Conclusion:Scutellarin has the potential to mitigate the overexpression of the cGAS/STING/NLRP3 signaling pathway within microglia following cerebral ischemia in rats,thereby attenuating microglia-mediated neuroinflammation.