Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou, People's Republic of China.
Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, People's Republic of China.
J Cell Physiol. 2019 Aug;234(10):17946-17958. doi: 10.1002/jcp.28427. Epub 2019 Mar 4.
To identify the effects of running on articular cartilage and subchondral bone remodeling, C57BL/6 mice were randomly divided into three groups: control, moderate-, and strenuous running. Magnetic resonance imaging showed bone marrow lesions in the knee subchondral bone in the strenuous-running group in contrast with the other two groups. The microcomputed tomography analysis showed promoted bone formation in the subchondral bone in mice subjected to strenuous running. Histological and immunohistochemistry results indicated that terminal differentiation of chondrocytes and degeneration of articular cartilage were enhanced but, synthesis of platelet-derived growth factor-AA (PDGF-AA) in the subchondral bone was suppressed after strenuous running. In vitro, excessive mechanical treatments suppressed the expression of PDGF-AA in osteoblasts, and the condition medium from mechanical-treated osteoblasts stimulated maturation and terminal differentiation of chondrocytes. These results indicate that strenuous running suppresses the synthesis of PDGF-AA in subchondral bone, leading to downregulated PDGF/Akt signal in articular cartilage and thus cartilage degeneration.
为了明确跑步对关节软骨和软骨下骨重塑的影响，将 C57BL/6 小鼠随机分为三组：对照组、中等强度跑步组和高强度跑步组。磁共振成像显示，与其他两组相比，高强度跑步组的膝关节软骨下骨有骨髓病变。微计算机断层扫描分析显示，高强度跑步组的软骨下骨有促进骨形成的现象。组织学和免疫组织化学结果表明，软骨细胞的终末分化和关节软骨的退变在高强度跑步后增强，但软骨下骨中血小板衍生生长因子-AA（PDGF-AA）的合成受到抑制。在体外，过度的机械处理抑制了成骨细胞中 PDGF-AA 的表达，而机械处理后的成骨细胞条件培养基刺激了软骨细胞的成熟和终末分化。这些结果表明，高强度跑步抑制了软骨下骨中 PDGF-AA 的合成，导致关节软骨中 PDGF/Akt 信号下调，从而导致软骨退变。
