Department of Orthopedics, First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China.
Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing 210029, China.
J Immunol. 2019 Jul 15;203(2):485-492. doi: 10.4049/jimmunol.1801513. Epub 2019 May 31.
Osteoarthritis (OA) is a degenerative joint disease that causes chronic disability among the elderly. Despite recent advances in symptomatic management of OA by pharmacological and surgical approaches, there remains a lack of optimal approaches to manage inflammation in the joints, which causes cartilage degradation and pain. In this study, we investigated the efficacy and underlying mechanisms of nicotine exposure in attenuating joint inflammation, cartilage degradation, and pain in a mouse model of OA. A mouse model of OA was induced by injection of monosodium iodoacetate into the knee joint. Cell culture models were also used to study the efficacy and underlying mechanisms of nicotine treatment in attenuating symptoms of OA. Nicotine treatment reduced mechanical allodynia, cartilage degradation, and the upregulation of matrix metalloproteinase-9 (MMP-9), a hallmark of joint inflammation in OA, in mice treated with monosodium iodoacetate. The effects of nicotine were abolished by the selective α7 nicotinic acetylcholine receptor (nAChR) blocker, methyllycaconitine . In RAW264.7 cells and murine primary bone marrow-derived macrophages, nicotine significantly inhibited MMP-9 production induced by LPS. In addition, nicotine significantly enhanced PI3K/Akt and inhibited NF-κB translocation from the cytosol to the nucleus in an α7-nAChR-dependent manner, suggesting that nicotine acts on α7-nAChRs to inhibit MMP-9 production by macrophages through modulation of the PI3K/Akt-NF-κB pathway. Our results provide novel evidence that nicotine can attenuate joint inflammation and pain in experimental OA via α7-nAChRs. α7-nAChR could thus serve as a highly promising target to manage joint inflammation and pain in OA.
骨关节炎(OA)是一种退行性关节疾病,会导致老年人慢性残疾。尽管最近在 OA 的症状管理方面取得了药理学和手术方法的进展,但仍缺乏管理关节炎症的最佳方法,而炎症会导致软骨降解和疼痛。在这项研究中,我们研究了尼古丁暴露在减轻 OA 小鼠模型中的关节炎症、软骨降解和疼痛中的疗效和潜在机制。通过向膝关节注射单碘乙酸钠诱导 OA 小鼠模型。还使用细胞培养模型来研究尼古丁治疗减轻 OA 症状的疗效和潜在机制。尼古丁治疗可减轻机械性痛觉过敏、软骨降解以及基质金属蛋白酶-9(MMP-9)的上调,MMP-9 是 OA 关节炎症的标志。单碘乙酸钠处理的小鼠中,MMP-9 的上调。选择性α7 烟碱型乙酰胆碱受体(nAChR)阻滞剂甲基戊烯宁消除了尼古丁的作用。在 RAW264.7 细胞和小鼠原代骨髓来源的巨噬细胞中,尼古丁可显著抑制 LPS 诱导的 MMP-9 产生。此外,尼古丁以α7-nAChR 依赖的方式显著增强 PI3K/Akt 并抑制 NF-κB 从细胞质向细胞核易位,表明尼古丁通过调节 PI3K/Akt-NF-κB 通路作用于α7-nAChR 来抑制巨噬细胞中 MMP-9 的产生。我们的研究结果为尼古丁通过α7-nAChRs 减轻实验性 OA 中的关节炎症和疼痛提供了新的证据。因此,α7-nAChR 可作为管理 OA 中关节炎症和疼痛的极具前景的靶点。