Tanishima Shinji, Kishimoto Yuji, Fukata Satoru, Mizumura Hiroyuki, Hagino Hiroshi, Teshima Ryota
Division of Orthopedic Surgery, Department of Medicine of Sensory and Motor Organs, Faculty of Medicine, Tottori University, Yonago 683-8504, Japan.
Mod Rheumatol. 2007;17(3):198-205. doi: 10.1007/s10165-007-0566-y. Epub 2007 Jun 20.
We investigated the inhibitory mechanism of bone resorption by minodronic acid in collagen-induced arthritis (CIA) in rats. Four groups of female Sprague-Dawley rats, aged 7 months, were studied: three groups of collagen-sensitized rats, including one placebo-administered group (CIA-P), and two minodronic acid-administered groups at 0.2 mg/kg/2 day (CIA-BIS) and 2.0 mg/kg/2 day (CIA-BIS10). These were studied with an additional untreated observation group (Cont group). Minodronic acid was administered orally a day after the initial sensitization. The femoral posteromedial condyle was analyzed histologically and immunohistologically 4 weeks after the initial sensitization. Western blotting was also performed to assess the receptor activator of nuclear factor kappaB (RANK), RANK ligand (RANKL), and osteoprotegerin (OPG) expression of the knee joints. In CIA-P rats, many tartrate-resistant acid phosphatase (TRAP)-positive cells were found at the pannus-lining layer and the epiphyseal medulla. The bone-lining cells in the epiphyseal medulla and the cells in the pannus strongly expressed RANK and RANKL. In the minodronic acid-administered group, the number of TRAP-positive cells and the severity of arthritis were reduced. The reduction in the CIA-BIS10 group was significant compared with the CIA-P group (P < 0.05). Dosage-dependent reduction of RANK and RANKL expression was confirmed by immunohistology and Western blotting. With or without minodronic acid administration, no apoptotic cells were found in any groups using the TdT-mediated dUTP-biotinnick end labeling (TUNEL) method. The expression of OPG was not clear in all groups. These results demonstrated that minodronic acid inhibited the differentiation and the activation of osteoclasts not by inducing apoptosis but by inhibiting the RANKL-RANK system, and thereby suppressing bone resorption.
我们研究了米诺膦酸对大鼠胶原诱导性关节炎（CIA）骨吸收的抑制机制。研究了四组7月龄雌性斯普拉格-道利大鼠：三组胶原致敏大鼠，包括一组给予安慰剂的组（CIA-P），以及两组分别给予0.2mg/kg/2天（CIA-BIS）和2.0mg/kg/2天（CIA-BIS10）米诺膦酸的组。另外设置了一个未处理的观察组（对照组）。在初次致敏一天后口服米诺膦酸。初次致敏4周后，对股骨后内侧髁进行组织学和免疫组织学分析。还进行了蛋白质免疫印迹法以评估膝关节中核因子κB受体激活剂（RANK）、RANK配体（RANKL）和骨保护素（OPG）的表达。在CIA-P大鼠中，在血管翳内衬层和骨骺髓质中发现许多抗酒石酸酸性磷酸酶（TRAP）阳性细胞。骨骺髓质中的骨衬细胞和血管翳中的细胞强烈表达RANK和RANKL。在给予米诺膦酸的组中，TRAP阳性细胞数量和关节炎严重程度降低。与CIA-P组相比，CIA-BIS10组的降低具有显著性（P<0.05）。免疫组织学和蛋白质免疫印迹法证实了RANK和RANKL表达呈剂量依赖性降低。无论是否给予米诺膦酸，使用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（TUNEL）法在任何组中均未发现凋亡细胞。所有组中OPG的表达均不明确。这些结果表明，米诺膦酸不是通过诱导凋亡，而是通过抑制RANKL-RANK系统来抑制破骨细胞的分化和激活，从而抑制骨吸收。
