Ohta Kouichi, Kikuchi Takanobu, Arai Satoko, Yoshida Noriko, Sato Atsuko, Yoshimura Nagahisa
Department of Ophthalmology, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto 390 8621, Japan.
Exp Eye Res. 2003 Dec;77(6):665-73. doi: 10.1016/j.exer.2003.08.014.
Endotoxin-induced uveitis (EIU) is an animal model of acute ocular inflammation. Cytokines, chemokines, and nitric oxide (NO) have been reported to play important roles. We have determined whether heme oxygenase (HO)-1, a heat shock protein, can suppress EIU. EIU was induced by a footpad injection of lipopolysaccharide (LPS) in male Lewis rats. Hemin, an inducer of HO-1, was injected intraperitoneally 1 hr prior to the LPS injection. HO-1 and HO-2 expression in the iris-ciliary body (ICB) was studied by real time PCR and Western blot analysis. The number of infiltrating cells and the protein concentration in the aqueous humor (AqH) were evaluated by microscopy and by protein assay. The expression of inducible nitric oxide synthase (iNOS), interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, and IL-1beta mRNA was determined by real time PCR. The concentration of nitrate plus nitrite, and levels of IL-6 and TNF-alpha in the AqH were also evaluated by Griess reagents and by enzyme-linked immunosorbent assay, respectively. The expression of HO-1 mRNA and protein, induced by LPS, was enhanced significantly by pre-injection of hemin (P<0.001). HO-2 was constitutively present in the ICB and was not up-regulated by LPS or by hemin. The number of infiltrating cells and the concentration of protein in the AqH was significantly elevated by LPS injection, and hemin significantly reduced the number of cells and the protein concentration (P<0.0001). The expression of iNOS and IL-6 mRNA and protein were down-regulated by hemin (P<0.001). Hemin is effective in inducing HO-1 and in reducing the ocular inflammation induced by LPS probably by down-regulating NO and pro-inflammatory cytokine expression.
内毒素诱导性葡萄膜炎（EIU）是一种急性眼部炎症的动物模型。细胞因子、趋化因子和一氧化氮（NO）已被报道发挥重要作用。我们已确定热休克蛋白血红素加氧酶（HO）-1是否能抑制EIU。通过在雄性Lewis大鼠的足垫注射脂多糖（LPS）诱导EIU。在注射LPS前1小时腹腔注射HO-1的诱导剂血红素。通过实时PCR和蛋白质印迹分析研究虹膜睫状体（ICB）中HO-1和HO-2的表达。通过显微镜检查和蛋白质测定评估房水（AqH）中浸润细胞的数量和蛋白质浓度。通过实时PCR测定诱导型一氧化氮合酶（iNOS）、白细胞介素（IL）-6、肿瘤坏死因子（TNF）-α和IL-1β mRNA的表达。还分别通过格里斯试剂和酶联免疫吸附测定评估AqH中硝酸盐加亚硝酸盐的浓度以及IL-6和TNF-α的水平。LPS诱导的HO-1 mRNA和蛋白质的表达通过预先注射血红素而显著增强（P<0.001）。HO-2在ICB中组成性存在，且未被LPS或血红素上调。LPS注射显著提高了AqH中浸润细胞的数量和蛋白质浓度，而血红素显著减少了细胞数量和蛋白质浓度（P<0.0001）。血红素下调了iNOS和IL-6 mRNA及蛋白质的表达（P<0.001）。血红素可有效诱导HO-1并可能通过下调NO和促炎细胞因子的表达来减轻LPS诱导的眼部炎症。
