Herein, we found that serum concentration of superoxide dismutase 3 (SOD3) was significantly reduced in children with mycoplasma pneumonia (MP) infection. To study the roles of SOD3 in inflammatory regulation of MP infection, human A549 type II alveolar epithelial cells were stimulated with 10 7 CCU/ml of MP to build MP infection in vitro . Secretion of pro-inflammatory cytokine interleukin (IL)-8 and tumor necrosis factor (TNF)-α were measured via enzyme-linked immunosorbent assay (ELISA) to assess the inflammatory response of A549 cells. Levofloxacin (LVFX) was used as an anti-inflammatory drug while recombinant TNF-α was used as an inflammatory promotor in MP-infected cells. Transcriptional activity of nuclear factor (NF)-кB was assessed by detecting protein levels of nuclear NF-кB and cytoplasm NF-кB using Western blot analysis. Our data suggested that the expression of SOD3 mRNA and protein, as well as content of SOD3 in cultured supernatant, were time-dependently inhibited in MP-infected A549 cells. However, lentiviruses-mediated SOD3 overexpression alleviated inflammatory response of MP-infected A549 cells, and prevented the unclear translocation of NF-кB, as evidenced by obviously reducing the production of IL-8 and TNF-α in cell cultured supernatant, as well as decreasing nuclear NF-кB while increasing cytoplasm NF-кB. Inspiringly, SOD3 overexpression induced anti-inflammatory effect and the inactivation of NF-кB was similar to that of 2 μg/ml of LVFX, but reversed by additional TNF-α treatment. Therefore, we can conclude that transcriptional activity of NF-κB was the underlying mechanism, by which SOD3 regulated inflammatory response in MP infection in vitro .

中文翻译：

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超氧化物歧化酶 3 作为感染肺炎支原体的 A549 细胞的炎症抑制因子

在此，我们发现支原体肺炎 (MP) 感染儿童的血清超氧化物歧化酶 3 (SOD3) 浓度显着降低。为了研究 SOD3 在 MP 感染炎症调节中的作用，用 10 7 CCU/ml MP 刺激人 A549 II 型肺泡上皮细胞以在体外建立 MP 感染。通过酶联免疫吸附试验 (ELISA) 测量促炎细胞因子白细胞介素 (IL)-8 和肿瘤坏死因子 (TNF)-α 的分泌，以评估 A549 细胞的炎症反应。左氧氟沙星 (LVFX) 用作抗炎药，而重组 TNF-α 用作 MP 感染细胞的炎症启动子。通过使用蛋白质印迹分析检测核 NF-кB 和细胞质 NF-кB 的蛋白质水平来评估核因子 (NF)-кB 的转录活性。我们的数据表明，在 MP 感染的 A549 细胞中，SOD3 mRNA 和蛋白质的表达以及培养上清液中 SOD3 的含量受到时间依赖性抑制。然而，慢病毒介导的 SOD3 过表达减轻了 MP 感染的 A549 细胞的炎症反应，并防止了 NF-κB 的不清楚易位，这可以通过明显减少细胞培养上清液中 IL-8 和 TNF-α 的产生以及减少核 NF-кB，同时增加细胞质 NF-кB。令人鼓舞的是，SOD3 过表达诱导抗炎作用，NF-кB 的失活与 2 μg/ml LVFX 相似，但被额外的 TNF-α 处理逆转。因此，我们可以得出结论，NF-κB的转录活性是SOD3在体外调节MP感染炎症反应的潜在机制。