Wu Haichong, Jiang Kangfeng, Yin Nannan, Ma Xiaofei, Zhao Gan, Qiu Changwei, Deng Ganzhen
Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
Oncotarget. 2017 Mar 21;8(12):20042-20055. doi: 10.18632/oncotarget.15373.
The purpose of this study was to investigate the effects of thymol on lipopolysaccharide (LPS)-induced inflammatory responses and to clarify the potential mechanism of these effects. LPS-induced mouse endometritis was used to confirm the anti-inflammatory action of thymol in vivo. RAW264.7 cells were used to examine the molecular mechanism and targets of thymol in vitro. In vivo, thymol markedly alleviated LPS-induced pathological injury, myeloperoxidase (MPO) activity, and the production of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in mice. Further studies were performed to examine the expression of the Toll-like receptor 4 (TLR4) -mediated nuclear factor-κB (NF-κB) pathway. These results showed that the expression of the TLR4-mediated NF-κB pathway was inhibited by thymol treatment. In vitro, we observed that thymol dose-dependently inhibited the expression of TNF-α, IL-1β, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) in LPS-stimulated RAW264.7 cells. Moreover, the results obtained from immunofluorescence assays also indicated that thymol dose-dependently suppressed LPS-induced reactive oxygen species (ROS) production. Silencing of TLR4 inhibited NF-κB pathway activation. Furthermore, H2O2 treatment increased the phosphorylation of p65 and IκBα, which were decreased when treated with N-acetyl cysteine or thymol. In conclusion, the anti-inflammatory effects of thymol are associated with activation of the TLR4 or ROS signaling pathways, contributing to NF-κB activation, thereby alleviating LPS-induced oxidative and inflammatory responses.
本研究的目的是探讨百里香酚对脂多糖（LPS）诱导的炎症反应的影响，并阐明这些作用的潜在机制。采用LPS诱导的小鼠子宫内膜炎来证实百里香酚在体内的抗炎作用。利用RAW264.7细胞在体外研究百里香酚的分子机制和作用靶点。在体内，百里香酚显著减轻了LPS诱导的小鼠病理损伤、髓过氧化物酶（MPO）活性以及肿瘤坏死因子-α（TNF-α）和白细胞介素-1β（IL-1β）的产生。进一步开展研究以检测Toll样受体4（TLR4）介导的核因子-κB（NF-κB）信号通路的表达。这些结果表明，百里香酚处理可抑制TLR4介导的NF-κB信号通路的表达。在体外，我们观察到百里香酚在LPS刺激的RAW264.7细胞中剂量依赖性地抑制TNF-α、IL-1β、诱导型一氧化氮合酶（iNOS）和环氧化酶-2（COX-2）的表达。此外，免疫荧光分析结果还表明，百里香酚剂量依赖性地抑制LPS诱导的活性氧（ROS）产生。TLR4基因沉默抑制了NF-κB信号通路的激活。此外，H2O2处理增加了p65和IκBα的磷酸化，而用N-乙酰半胱氨酸或百里香酚处理时其磷酸化水平降低。总之，百里香酚的抗炎作用与TLR4或ROS信号通路的激活有关，促进了NF-κB的激活，从而减轻LPS诱导的氧化和炎症反应。
