Chang Yun-Hsiang, Horng Chi-Ting, Chen Yi-Hao, Chen Po-Liang, Chen Ching-Long, Liang Chang-Min, Chien Ming-Wei, Chen Jiann-Torng
Department of Ophthalmology, Tri-Service General Hospital, Taipei, Taiwan, Republic of China.
Invest Ophthalmol Vis Sci. 2008 Dec;49(12):5441-9. doi: 10.1167/iovs.08-1784. Epub 2008 Aug 21.
Glucosamine sulfate (GS) is a naturally occurring sugar that exerts immunosuppressive effects in vitro and in vivo. The authors investigated whether GS modulates the inflammatory reaction in endotoxin-induced uveitis (EIU) of rats and the mechanisms by which it exerts its effects.
Two-hundred micrograms of lipopolysaccharide (LPS) was injected subcutaneously into Lewis rats to induce EIU. Doses of GS (10, 100, or 1000 mg/kg) were divided into three aliquots and administered intraperitoneally 30 minutes before LPS injection, concurrently with LPS injection, and 30 minutes after LPS injection. Twenty-four hours after LPS injection, aqueous humor was collected for cell counting and measurement of protein concentration. Immunohistochemical staining of the iris-ciliary body was performed to evaluate the effects of GS on intercellular adhesion molecule (ICAM)-1 and nuclear factor (NF)-kappaB activation and to demonstrate macrophage infiltration. The effects of various doses of GS pretreatment were also examined using a mouse macrophage cell line (RAW264.7 cells) and LPS stimulation. Levels of prostaglandin (PG)-E2 and nitric oxide (NO) were determined. Expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 were measured using Western blot analysis. The effect of GS on LPS-induced NF-kappaB activation in RAW cells was also examined.
Cell counting and analysis of protein concentration in aqueous humor revealed that GS suppressed EIU in rats treated with a high dose of GS (1000 mg/kg). Immunohistochemistry showed that treatment with GS reduced ICAM-1 expression and suppressed activation of NF-kappaB in the iris-ciliary body. The main inflammatory cells in the iris-ciliary body during EIU were macrophages. In LPS-stimulated macrophage RAW cell culture, GS inhibited the production of NO and PG-E2, the expression of iNOS and COX-2, and the activation of NF-kappaB.
GS suppresses EIU in rats by blockading the NF-kappaB-dependent signaling pathway and the subsequent production of ICAM-1 and proinflammatory mediators. This study has extended the authors' previous observation that GS is a potentially important compound for reducing ICAM-1-mediated inflammatory effects in the eye.
硫酸葡萄糖胺（GS）是一种天然存在的糖类，在体外和体内均具有免疫抑制作用。作者研究了GS是否能调节大鼠内毒素诱导性葡萄膜炎（EIU）中的炎症反应及其发挥作用的机制。
将200微克脂多糖（LPS）皮下注射到Lewis大鼠体内以诱导EIU。GS剂量（10、100或1000毫克/千克）分为三等份，分别在LPS注射前30分钟、与LPS注射同时以及LPS注射后30分钟腹腔注射。LPS注射24小时后，收集房水进行细胞计数和蛋白质浓度测量。对虹膜睫状体进行免疫组织化学染色，以评估GS对细胞间黏附分子（ICAM）-1和核因子（NF）-κB激活的影响，并证明巨噬细胞浸润。还使用小鼠巨噬细胞系（RAW264.7细胞）和LPS刺激来检测不同剂量GS预处理的效果。测定前列腺素（PG）-E2和一氧化氮（NO）的水平。使用蛋白质印迹分析测量诱导型NO合酶（iNOS）和环氧化酶（COX）-2的表达。还检测了GS对RAW细胞中LPS诱导的NF-κB激活的影响。
房水细胞计数和蛋白质浓度分析显示，高剂量GS（1000毫克/千克）治疗的大鼠中，GS抑制了EIU。免疫组织化学表明，GS治疗降低了ICAM-1表达，并抑制了虹膜睫状体中NF-κB的激活。EIU期间虹膜睫状体中的主要炎症细胞是巨噬细胞。在LPS刺激的巨噬细胞RAW细胞培养中，GS抑制了NO和PG-E2的产生、iNOS和COX-2的表达以及NF-κB的激活。
GS通过阻断NF-κB依赖性信号通路以及随后ICAM-1和促炎介质的产生来抑制大鼠的EIU。本研究扩展了作者之前的观察结果，即GS是一种潜在的重要化合物，可减少ICAM-1介导的眼部炎症效应。
