Chi Zai-Long, Hayasaka Seiji, Zhang Xue-Yun, Cui Hu-Shan, Hayasaka Yoriko
Department of Ophthalmology, Graduate School of Medicine, University of Toyama, Toyama, Japan.
Invest Ophthalmol Vis Sci. 2007 Jun;48(6):2719-25. doi: 10.1167/iovs.06-0644.
Investigation of physiological anti-inflammatory mechanisms can contribute to the treatment of inflammatory disorders. The purpose of the present study was to investigate the effect of nicotine, a selective cholinergic agonist, on endotoxin-induced uveitis (EIU) in rats and the underlying molecular mechanism.
Lipopolysaccharide (LPS; endotoxin) and nicotine were injected intraperitoneally. Clinical scores were evaluated by slit lamp. Intracameral protein content and the number of cells were determined. Immunohistochemical reactivity of alpha7 nicotine acetylcholine receptor (alpha7nAChR) was examined in the iris and ciliary body (ICB). mRNA and protein levels of cytokines and chemokines were measured by real-time PCR and enzyme-linked immunosorbent assay.
After LPS injection, clinical scores, as well as protein content and number of cells in the aqueous humor increased during 18 to 36 hours. Nicotine inhibited the endotoxin-induced elevation of these levels. mRNA and protein of alpha7nAChR expression levels were significantly increased by LPS and/or nicotine injection. Nicotine showed no effects on endotoxin-induced elevation of mRNA levels in ICB. However, nicotine decreased the endotoxin-induced elevation of interleukin (IL)-6, IL-1beta, tumor necrosis factor (TNF)-alpha, cytokine-induced neutrophil chemoattractant (CINC)-1, and monocyte chemotactic protein (MCP)-1, but did not affect IL-10 in the serum and aqueous humor.
Nicotine attenuated endotoxin-induced uveitis through directly decreasing the levels of multiple cytokines and chemokines in the aqueous humor, but did not affect the mRNA levels of these factors. The findings suggest that the nicotinic anti-inflammatory pathway may be involved in the pathogenesis of EIU.
研究生理抗炎机制有助于炎症性疾病的治疗。本研究旨在探讨选择性胆碱能激动剂尼古丁对大鼠内毒素诱导性葡萄膜炎（EIU）的影响及其潜在分子机制。
腹腔注射脂多糖（LPS；内毒素）和尼古丁。通过裂隙灯评估临床评分。测定前房内蛋白质含量和细胞数量。检测虹膜和睫状体（ICB）中α7尼古丁乙酰胆碱受体（α7nAChR）的免疫组化反应性。通过实时PCR和酶联免疫吸附测定法测量细胞因子和趋化因子的mRNA和蛋白质水平。
注射LPS后，临床评分以及房水中蛋白质含量和细胞数量在18至36小时内增加。尼古丁抑制了内毒素诱导的这些水平的升高。LPS和/或尼古丁注射显著增加了α7nAChR表达水平的mRNA和蛋白质。尼古丁对内毒素诱导的ICB中mRNA水平升高没有影响。然而，尼古丁降低了内毒素诱导的白细胞介素（IL）-6、IL-1β、肿瘤坏死因子（TNF）-α、细胞因子诱导的中性粒细胞趋化因子（CINC）-1和单核细胞趋化蛋白（MCP）-1的升高，但不影响血清和房水中的IL-10。
尼古丁通过直接降低房水中多种细胞因子和趋化因子的水平减轻内毒素诱导的葡萄膜炎，但不影响这些因子的mRNA水平。这些发现表明烟碱抗炎途径可能参与EIU的发病机制。
