Iijima H, Aoyama T, Ito A, Yamaguchi S, Nagai M, Tajino J, Zhang X, Kuroki H
Department of Motor Function Analysis, Human Health Sciences, Graduate School of Medicine, Kyoto University, Japan.
Department of Development and Rehabilitation of Motor Function, Human Health Sciences, Graduate School of Medicine, Kyoto University, Japan.
Osteoarthritis Cartilage. 2015 Sep;23(9):1563-74. doi: 10.1016/j.joca.2015.04.015. Epub 2015 Apr 24.
Subchondral bone cyst (SBC) growth, caused by osteoclast activity during early knee osteoarthritis (OA) pathogenesis, should be treated to prevent further progressions of OA. In the present study, we evaluated the effects of gentle treadmill walking on subchondral bone and cartilage changes in an experimental rat model of destabilized medial meniscus (DMM).
Twelve-week-old Wistar rats underwent DMM surgery in their right knee and sham surgery in their left knee and were assigned to either the sedentary group or walking group (n = 42/group). Animals in the walking group were subjected to treadmill exercise 2 days after surgery, which included walking for 12 m/min, 30 min/day, 5 days/week for 1, 2, and 4 week(s). Subchondral bone and cartilage changes were evaluated by micro-CT analysis, histological analysis, and biomechanical analysis.
Treadmill walking had a tendency to suppress SBC growth, which was confirmed by micro-CT (P = 0.06) and positive staining for tartrate-resistant acid phosphatase (TRAP) activity for the osteoclast number per bone surface (P = 0.09) 4 weeks after surgery. These changes coincide with the prevention of cartilage degeneration as evaluated by the Osteoarthritis Research Society International (OARSI) score (P < 0.05) and biomechanically softening (P < 0.05). Furthermore, treadmill walking could suppressed increasing osteocyte deaths (P < 0.01), which was positively correlated with the OARSI score (r = 0.77; P < 0.01).
These results indicate biomechanical and biological links exist between cartilage and subchondral bone; preventive effects of treadmill walking on subchondral bone deterioration might be partly explained by the chondroprotective effects.
在早期膝骨关节炎（OA）发病机制中，破骨细胞活动会导致软骨下骨囊肿（SBC）生长，应对此进行治疗以防止OA进一步发展。在本研究中，我们评估了在不稳定内侧半月板（DMM）实验大鼠模型中，温和的跑步机行走对软骨下骨和软骨变化的影响。
12周龄的Wistar大鼠右膝接受DMM手术，左膝接受假手术，并被分为久坐组或行走组（每组n = 42）。行走组的动物在手术后2天开始进行跑步机运动，包括以12米/分钟的速度行走，每天30分钟，每周5天，持续1、2和4周。通过显微CT分析、组织学分析和生物力学分析评估软骨下骨和软骨的变化。
跑步机行走有抑制SBC生长的趋势，术后4周通过显微CT（P = 0.06）和抗酒石酸酸性磷酸酶（TRAP）活性对每骨表面破骨细胞数量的阳性染色（P = 0.09）得到证实。这些变化与通过国际骨关节炎研究学会（OARSI）评分评估的软骨退变预防（P < 0.05）和生物力学软化（P < 0.05）相一致。此外，跑步机行走可抑制骨细胞死亡增加（P < 0.01），这与OARSI评分呈正相关（r = 0.77；P < 0.01）。
这些结果表明软骨和软骨下骨之间存在生物力学和生物学联系；跑步机行走对软骨下骨恶化的预防作用可能部分由软骨保护作用来解释。
