淫羊藿苷对补体旁路激活诱导的小鼠急性肺损伤的保护作用

摘要

目的 探讨淫羊藿苷( ICA)对补体旁路激活造成的小鼠急性肺损伤的保护作用及作用机制.方法 32只昆明小鼠随机分为正常对照组、模型组、PDTC组、淫羊藿苷组,预防给药7d 后,用特异性补体旁路激活蛋白眼镜蛇毒因子(CVF),尾静脉注射复制小鼠急性肺损伤模型.测定小鼠支气管肺泡灌洗液( BALF)中蛋白含量和炎性细胞数目;肺组织匀浆后测定髓过氧化物酶( MPO)活性; ELISA 法检测BALF和血清中 IL-6、TNF-α、P-selectin、ICAM-1 的含量;HE染色法观察肺组织病理形态学变化;免疫组化法测定肺组织中NF-κB p65的磷酸化水平,并采用双萤光素酶报告基因检测系统,在细胞水平上测定补体旁路激活对微血管内皮细胞中NF-κB的核内转录活性的影响.结果 ICA可以明显降低小鼠肺组织匀浆液中 MPO 含量和 BALF 中炎性细胞数目,并同时降低BALF中IL-6、TNF-α、P-selectin含量和血清中TNF-α、P-selectin、ICAM-1 水平,减轻小鼠肺部炎性细胞浸润,明显抑制小鼠肺组织中NF-κB p65 的磷酸化,并有效抑制NF-κB核内转录活性的上调.结论 ICA能有效减轻补体旁路激活诱导的小鼠肺部急性炎症反应,其机制可能与抑制肺组织炎性细胞浸润、NF-κB p65的磷酸化及核内转录活性,从而降低炎症反应水平有关.%Aim To explore the protective effect and mechanism of icariin ( ICA ) on acute lung injury ( ALI) in mice induced by activation of the comple-ment alternative pathway. Methods 32 healthy KM mice were randomly divided into four groups: the nor-mal group, the model group, the PDTC group and the Icariin group, which received 7-day intragastric admin-istration respectively. Then cobra venom factor ( CVF) was used to activate specifically complement alternative pathway to induce acute lung injury in mice by intrave-nous injection. Myeloperoxidase ( MPO ) activity of lung homogenate, the cell count and the protein con- tent of bronchoalveolar lavage fluid ( BALF ) were measured. The concentration of IL-6, TNF-α, P-selec-tin and ICAM-1 in BALF and serum were determined by ELISA. The pathological change of lung tissue was observed by HE staining. The phosphorylation of NF-κB p65 in lung tissues was checked by immunohisto-chemistry. The effect of the transcriptional activity of NF-κB signal pathway in microvascular endothelial cells was measured by employing dual-luciferase re-porter assay system. Results ICA reduced MPO ac-tivity of lung homogenate, the cell count and the con-tent of IL-6, TNF-α, P-selectin in BALF obviously. The level of TNF-α, P-selectin and ICAM-1 in serum was decreased, the pulmonary inflammatory cell infil-tration was reduced, the phosphorylation of NF-κB p65 in lung was inhibited significantly and the transcrip-tional activity of NF-κB was also down-regulated. Con-clusion ICA can alleviate acute inflammatory re-sponse of ALI mice induced by activation of the com-plement alternative pathway. The mechanism may be highly related to the inhibition of inflammatory cell in-filtration in lung tissue, the down-regulation of phos-phorylation of NF-κB p65 and nuclear transcriptional activity.