Muraoka Tomoya, Hagino Hiroshi, Okano Toru, Enokida Makoto, Teshima Ryota
Tottori University, Yonago, Japan.
Arthritis Rheum. 2007 Oct;56(10):3366-74. doi: 10.1002/art.22921.
To evaluate the relationships among cartilage and subchondral bone before and after the onset of cartilage degeneration in the Hartley guinea pig model of spontaneous osteoarthritis (OA) as compared with those in Weiser-Maple guinea pigs, which do not develop OA.
Mice from each strain were used at ages 2, 3, 5, and 8 months (n = 7 at each time point). The region observed was the medial tibial plateau. Cartilage degeneration was evaluated histologically. Subchondral bone structure was evaluated based on subchondral bone plate thickness and subchondral cancellous bone trabecular parameters calculated from the microfocal computed tomography 3-dimensional reconstruction image. The bone mineral density (BMD) of the subchondral cancellous bone as well as levels of urinary N-telopeptide of type I collagen (NTX) and serum osteocalcin (OC) were measured.
In Hartley guinea pigs, the number of chondrocytes in the surface layer started to decrease at 3 months. At 8 months, fibrillation expanded to the radial zone. In Weiser-Maple guinea pigs, no cartilage degeneration was noted even at 8 months. Subchondral bone plate thickness was significantly lower in Hartley guinea pigs than in Weiser-Maple guinea pigs at 2 months. The subchondral bone had a rod-like and convex structure at 2 months in Hartley guinea pigs. BMD was significantly lower in Hartley guinea pigs than in Weiser-Maple guinea pigs at 2 months. The serum OC level was significantly higher in Hartley guinea pigs than in Weiser-Maple guinea pigs at 2 months and 3 months, whereas the urinary NTX level was significantly lower in Hartley guinea pigs at 3 months.
Subchondral bone is fragile, and bone formation may be promoted in subchondral bone before the onset of cartilage degeneration in Hartley guinea pigs. Subchondral bone may be involved in the development of OA.
评估自发性骨关节炎（OA）的哈特利豚鼠模型中软骨退变发生前后软骨与软骨下骨之间的关系，并与未发生OA的韦泽-梅普尔豚鼠进行比较。
每个品系的小鼠在2、3、5和8月龄时使用（每个时间点n = 7）。观察区域为胫骨内侧平台。通过组织学评估软骨退变情况。基于从微焦点计算机断层扫描三维重建图像计算得出的软骨下骨板厚度和软骨下松质骨小梁参数评估软骨下骨结构。测量软骨下松质骨的骨密度（BMD）以及尿I型胶原N-端肽（NTX）水平和血清骨钙素（OC）水平。
在哈特利豚鼠中，表层软骨细胞数量在3月龄时开始减少。8月龄时，纤维化扩展至放射状区域。在韦泽-梅普尔豚鼠中，即使在8月龄时也未观察到软骨退变。在2月龄时，哈特利豚鼠的软骨下骨板厚度显著低于韦泽-梅普尔豚鼠。在2月龄时，哈特利豚鼠的软骨下骨呈棒状且凸起结构。在2月龄时，哈特利豚鼠的BMD显著低于韦泽-梅普尔豚鼠。在2月龄和3月龄时，哈特利豚鼠的血清OC水平显著高于韦泽-梅普尔豚鼠，而在3月龄时，哈特利豚鼠的尿NTX水平显著较低。
软骨下骨较为脆弱，并可能在哈特利豚鼠软骨退变发生前促进软骨下骨的骨形成。软骨下骨可能参与OA的发生发展。
