Ainola M, Mandelin J, Liljeström M, Konttinen Y T, Salo J
Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland.
Clin Exp Rheumatol. 2008 Mar-Apr;26(2):240-6.
To test if the pannus tissue is characterized by a high receptor activator of nuclear factor kappaB ligand to osteoprotegerin (RANKL:OPG) ratio, which could explain local osteoclastogenesis and formation of bony erosions.
Messenger RNA and protein expressions of RANKL and OPG in rheumatoid and osteoarthritic tissue samples were measured using quantitative real-time RT-PCR and Western blot/densitometry. Pannus and synovitis fibroblasts explanted from tissue samples were cultured in vitro without and with TNF-alpha, IL-1Beta or IL-17 and analyzed quantitatively for RANKL expression. The ability of pannus fibroblasts to induce formation of multinuclear osteoclast-like cells from human monocytes, with macrophage-colony stimulating factor (M-CSF) but without RANKL added, was tested. Histochemical staining was used to assess the eventual presence of RANKL and tartrate resistant acid phosphatase positive osteoclast-like cells at the pannus-bone interface.
RANKL:OPG ratios of messenger RNA (p<0.05) and protein level were high in pannus (2.06+/-0.73 and 2.2+/-0.65) compared to rheumatoid (0.62+/-0.13 and 1.31+/-0.69) and osteoarthritis (0.62+/-0.32 and 0.52+/-0.16) synovial membranes. Resting and stimulated (p dependent on the cytokine used) pannus fibroblasts produced RANKL in excess (p=0.0005) and unstimulated pannus fibroblasts also effectively induced osteoclast-like cell formation from monocytes in vitro without any exogenous RANKL added. Compatible with these findings, multinuclear osteoclasts-like cells were frequent in the fibroblast- and macrophage-rich pannus tissue at the soft tissue-to-bone interface.
The high RANKL:OPG ratio, together with close fibroblast-to-monocyte contacts in pannus tissue, probably favor local generation of bone resorbing osteoclasts at the site of erosion in rheumatoid arthritis.
检测血管翳组织是否具有高核因子κB受体活化因子配体与骨保护素（RANKL:OPG）比值，这可能解释局部破骨细胞生成及骨侵蚀的形成。
采用定量实时逆转录聚合酶链反应（RT-PCR）及蛋白质免疫印迹/密度测定法，检测类风湿性关节炎和骨关节炎组织样本中RANKL和OPG的信使核糖核酸（mRNA）及蛋白表达。从组织样本中分离出的血管翳及滑膜炎成纤维细胞，分别在无肿瘤坏死因子-α（TNF-α）、白细胞介素-1β（IL-1β）或白细胞介素-17以及有上述细胞因子的情况下进行体外培养，并对RANKL表达进行定量分析。检测血管翳成纤维细胞在添加巨噬细胞集落刺激因子（M-CSF）但不添加RANKL的情况下，诱导人单核细胞形成多核破骨细胞样细胞的能力。采用组织化学染色法评估血管翳-骨界面处RANKL及抗酒石酸酸性磷酸酶阳性破骨细胞样细胞的最终存在情况。
与类风湿性关节炎（mRNA比值为0.62±0.13，蛋白水平比值为1.31±0.69）及骨关节炎（mRNA比值为0.62±0.32，蛋白水平比值为0.52±0.16）滑膜相比，血管翳中RANKL:OPG的mRNA（p<0.05）及蛋白水平比值较高（分别为2.06±0.73和2.2±0.65）。静息及刺激状态下（p值取决于所使用的细胞因子）的血管翳成纤维细胞均过量产生RANKL（p=0.0005），且未受刺激的血管翳成纤维细胞在体外不添加任何外源性RANKL的情况下，也能有效诱导单核细胞形成破骨细胞样细胞。与这些结果相符的是，在软组织-骨界面富含成纤维细胞和巨噬细胞的血管翳组织中，多核破骨细胞样细胞很常见。
高RANKL:OPG比值，以及血管翳组织中成纤维细胞与单核细胞的紧密接触，可能有利于类风湿性关节炎侵蚀部位局部产生骨吸收破骨细胞。
