脂氧素对脂多糖诱导巨噬细胞炎症相关因子的影响及机制

目的：研究脂氧素（1ipoxin A4）对脂多糖（1ipopo-lysaccharide，LPS）诱导的小鼠巨噬细胞株RAW264.7中相关炎症因子如肿瘤坏死因子（TNF-α）、环加氧酶-2（COX-2）、前列腺素E2（PGE2）、血红素氧化酶-1（HO-1）和白介素-10（IL-10）的影响，并进一步探讨其内在分子机制。方法：以1mg／L LPS刺激体外培养的RAW264.7细胞作为炎症模型，分别用脂氧素A4或脂氧素A4和ZnPPIX干预LPS刺激的RAW264.7细胞24h后，收集培养上清并提取细胞总蛋白，酶联免疫法测定上清中TNF-α，IL-10和PGE2浓度，免疫印迹法检测细胞COX-2和HO-1的蛋白表达量，分光光度计分析HO-1的活性。结果：1mg／L LPS明显诱导TNF-α，COX-2和PGE，的生成，也适度增加IL-10及HO-1的产生；脂氧素A4可抑制LPS诱导的TNF-α（P〈0.01雠LPS组），COX-2和PGE2（P〈0.01伽LPS组）的生成，却进一步增加IL-10（P〈0.01 vs LPS组）和HO-1表达量和活性（P〈0.01 vs LPS组）；ZnPPIX可减弱脂氧素A。对LPS诱导TNF-α（P〈0.05 vs LPS＋脂氧素A4组），COX-2和PGE2（P〈0.05 vs LPS＋脂氧素A4组）的生成抑制作用，同时也下调IL-10的生成量。结论：脂氧素A4可抑制LPS诱导的巨噬细胞中致炎介质TNF-α，COX-2及PGE2的生成，同时也促进IL-10的产生，这种效应在一定程度上是通过上调HO-1表达和活性实现。

Effects and mechanism of lipoxin on LPS-induced inflammatory mediators in RAW264.7 macrophages

AIM： To investigate the effects of lipoxin A4 on lipopolysaccharide （LPS）-induced inflammatory mediators in RAW264.7 macrophages and its underlying molecular mechanism. METHODS： RAW264.7 cells were stimulated with 1 mg/L LPS to induce inflammatory response and then lipoxin A4 at 100 ng/mL was administrated. ZnPPIX was added to RAW264. 7 cells by eotreatment of LPS and lipoxin An. The concentrations of TNF-α, IL-10 and PGE2 in the cell supernatants were measured by ELISA. COX-2 and HO-1 proteins were detected by Western blotting and HO-1 activity was analyzed by spectrophotometer. RESULTS： Compared with that in LPS group, lipoxin A4 significantly inhibited LPS-induced COX-2 protein expression and levels of TNF-α and PGE2 in RAW264.7 cells （ both, P 〈0.01） and this effect was accompanied by a parallel increase in HO-1 and IL-10（P〈0.01）. Treatment of ZnPPIX partially abolished the suppressive effects of lipoxin A4 on COX-2 protein expression and the levels of TNF-α and PGE2 in RAW264.7 cells induced by LPS, compared with those in LPS ＋ Lipoxin A4 group （ both, P 〈0.05）. CONCLUSION： Lipoxin A4 inhibits LPS-induced proinflammatory mediators, including COX-2, PGE2 and TNF-α,possibly by mediation through HO-1 pathway.