旋覆花内酯通过抑制炎症反应对缺血脑组织发挥保护作用

Acetylbritannilactone exerts the neuroprotective effect on ischemic cerebral tissues by inhibiting the inflammatory responses

目的探讨旋覆花内酯(Acetylbritannilactone,ABL)通过抑制炎症反应对小鼠缺血性脑组织发挥保护作用及其机制。方法线栓法建立CD1小鼠大脑中动脉闭塞(middle cerebral artery occlusion,MCAO)模型。实验分为假手术组、MCAO组、ABL小剂量组(10mg/kg)和ABL大剂量组(30mg/kg)。ABL于术前30min腹腔注射,术后24h后处死小鼠。各组取材前进行神经功能评分,分别用Western blotting和RT-PCR的方法检测缺血脑组织中肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)、白细胞介素1β(interleukin-1β,IL-1β)、Toll样受体4(Tolllike receptors 4,TLR4)、肿瘤坏死因子受体相关因子6(tumor necrosis receptor associated factor 6,TRAF6)和核因子κB(nuclear factor-kappaB,NF-κB)蛋白和基因水平的变化,并观察神经功能、脑水肿程度和脑梗死体积。结果与假手术组比较,MCAO组TNF-α、IL-1β、TLR4、TRAF6和NF-κB蛋白和基因表达水平明显升高(P<0.05);ABL能够显著下调炎症因子TNF-α、IL-1β的表达,降低TLR4、TRAF6和NF-κB的水平(P<0.05),明显改善神经功能、减轻脑水肿、减小梗死体积(P<0.05)。结论 ABL通过抑制脑缺血引发的TLR4/TRAF6/NF-κB级联途径减少TNF-α、IL-1β的表达,发挥对缺血脑组织的抗炎作用,同时改善了脑缺血后小鼠神经功能缺损,减轻脑水肿,减小梗死体积,起到神经保护作用。

Objective This study is to explore the protective role and mechanism of Acetylbritannilactone（ABL）on inflammatory responses induced by focal cerebral ischemia in mice.Methods Male CD1 mice were subjected to permanent middle cerebral artery occlusion（MCAO）.The mice were randomly divided into sham-operated group,MCAO group,ABL-L group（10mg/kg）and ABL-H group（30mg/kg）.ABL was injected intraperitoneally 30 minutes prior to MCAO operation.Mice were anesthetized and sacrificed at 24 hafter stroke.Western blotting and RT-PCR were used to examine the expression of tumor necrosis factor-α（TNF-α）,interleukin-1β（IL-1β）,Toll-like receptor 4（TLR4）,tumor necrosis receptor associated factor 6（TRAF6）and nuclear factor-kappa B（NF-κB）.And the neurological deficit scores,brain water content and infarct volume were explored.Results Compared to sham group,the expressions of TNF-α,IL-1β,TLR-4,TRAF6 and NF-κB were significantly increased in MCAO group（P 0.05）.ABL treatment markedly down-regulated expressions of TNF-α,IL-1β,TLR4,TRAF6,and NF-κB（P0.05）.The neurological deficit scores,infarct volume and brain water content were alleviated compared to MCAO group（P0.05）.Conclusion ABL treatment effectively ameliorates neurological defect, brain edema and brain infarct volume.ABL decreases inflammatory responses by suppressing the expression of the proinflammatory signaling molecules TLR4,TRAF6 and NF-κB,inhibiting TNF-αand IL-1βexpression in ischemic cerebral tissue of MCAO mice.