目的 探讨穿心莲内酯对脂多糖诱导RAW264.7细胞炎症反应的抑制作用及其作用机制。方法 采用噻唑蓝比色（MTT）法分析穿心莲内酯对RAW264.7细胞活力的影响。通过脂多糖处理RAW264.7细胞24 h建立细胞炎症模型，造模前1 h用穿心莲内酯2.5、5、10、20 μmol/L预处理。荧光定量PCR法检测RAW264.7细胞内相关抗氧化应激酶基因和iNOS水平。穿心莲内酯单独处理RAW264.7细胞24 h，Western blotting法检测Keap1/Nrf2/HO-1信号通路相关蛋白和Keap1、Nrf2、HO-1蛋白水平。免疫荧光检测转录因子Nrf2在胞质及核内的分布情况。结果 与对照组比较，穿心莲内酯剂量相关性地抑制RAW264.7细胞活力，差异具有统计学意义（P< 0.05、0.01、0.001）。穿心莲内酯显著抑制脂多糖诱导RAW264.7细胞的iNOS水平（P< 0.001），增加相关抗氧化酶基因HO-1、NQO1 mRNA水平。穿心莲内酯抑制Keap1表达，增加Nrf2和HO-1蛋白水平的表达。结论 穿心莲内酯可抑制脂多糖诱导的炎症反应，其作用机制可能与激活Keap1/Nrf2/HO-1信号通路从而调控抗氧化酶HO-1、NQO1 mRNA表达水平相关。

Objective To study the anti-inflammatory effect of andrographolide on inflammation suppression induced by lipopolysaccharide, and explore its mechanism. Methods Cell viability of RAW264.7 cells treated with andrographolide were analyzed by MTT assay. Cell inflammatory model was established with RAW264.7 cells treated with lipopolysaccharide for 24 h prior to incubation of 2.5, 5, 10, and 20 μmol/L andrographolide for 1 h. Anti-oxidative enzymes and iNOS were evaluated by quantitative real-time polymerase chain reaction. RAW264.7 cells were treated with andrographolide for 24 h, and Keap1, Nrf2, and HO-1 expression were detected by Western blotting. Nrf2 distribution between cytosome and nucleus were analyzed by immunocytochemistry. Results Compared with the control group, cell survival rate of RAW264.7 cells were decreased treated by andrographolide in a dose-dependent manner (P < 0.05, 0.01, and 0.001). Andrographolide could significantly inhibit iNOS levels in RAW264.7 cells induced by lipopolysaccharide (P < 0.001), and could increase the levels of related antioxidant enzymes genes HO-1, NQO1 and mRNA. Andrographolide inhibited the expression of Keap1 and increased the expression of Nrf2 and HO-1 protein levels. Conclusion Andrographolide can inhibit the inflammatory response induced by lipopolysaccharide, and its mechanism may be related to activation of Keap1/Nrf2/HO-1 signaling pathway and regulation of expression levels of antioxidant enzymes HO-1 and NQO1 mRNA.

国家自然科学基金资助项目（81360625）