1Department of Rehabilitation Science, Graduate School of Health Sciences, Kobe University, Kobe, Japan.
2Life and Medical Sciences Area, Health Sciences Discipline, Kobe University, Kobe, Japan.
Physiol Int. 2024 Sep 2;111(3):271-286. doi: 10.1556/2060.2024.00418. Print 2024 Sep 18.
Maintaining intrinsic articular cartilage homeostasis is essential for the health of cartilage. However, the impact of aerobic exercise of varying intensities on the articular cartilage homeostasis has never been studied. This study aims to elucidate the influence of different aerobic exercise intensities on the anabolic and catabolic processes within articular cartilage.
Forty-eight male C57BL/6J mice, aged 7 weeks, were divided into 4 aerobic exercise groups and 1 control group. The aerobic exercise groups were subjected to both acute and chronic exercise protocols with varying intensities of 8, 12, 16, 20, and 24 m min-1. Total RNA from the knee joint cartilage was extracted in both phases to quantify mRNA of anabolic (Sox9, Col2a1, and Acan) and catabolic (MMP-13 and ADAMTS5) markers. In the chronic exercise, articular cartilage thickness and chondrocyte density were histologically assessed. Additionally, immunohistochemical staining quantified relevant molecules involved in cartilage metabolism.
In the acute exercise, the 8 m min-1 group exhibited reduced ADAMTS5 expression compared to the control, 16 m min-1, and 24 m min-1 groups. Chronic exercise showed enhanced articular cartilage thickness in both the 8 and 12 m min-1 groups relative to the control group. Moreover, the 8 m min-1 group demonstrated elevated aggrecan levels in comparison to both the control and 24 m min-1 groups. Additionally, the 24 m min-1 group exhibited significantly higher ADAMTS5 levels than the control group.
Our findings suggest that consistent low-intensity aerobic exercise suppresses catabolic molecule expression in articular cartilage, thereby fostering anabolic activity. Conversely, continuous high-intensity aerobic exercise can potentially disrupt cartilage homeostasis by enhancing catabolic processes. This dichotomy underscores the need for balanced exercise regimens to maintain cartilage health.
维持关节内软骨的内在稳态对于软骨健康至关重要。然而，不同强度的有氧运动对关节软骨稳态的影响从未被研究过。本研究旨在阐明不同强度的有氧运动对关节软骨内合成代谢和分解代谢过程的影响。
将 48 只 7 周龄雄性 C57BL/6J 小鼠分为 4 个有氧运动组和 1 个对照组。有氧运动组分别进行急性和慢性运动方案，强度分别为 8、12、16、20 和 24 m min-1。在两个阶段从膝关节软骨中提取总 RNA，以定量分析合成代谢（Sox9、Col2a1 和 Acan）和分解代谢（MMP-13 和 ADAMTS5）标志物的 mRNA。在慢性运动中，对关节软骨厚度和软骨细胞密度进行组织学评估。此外，免疫组织化学染色定量评估了参与软骨代谢的相关分子。
在急性运动中，与对照组、16 m min-1 和 24 m min-1 组相比，8 m min-1 组的 ADAMTS5 表达减少。慢性运动显示，与对照组相比，8 m min-1 和 12 m min-1 组的关节软骨厚度增加。此外，与对照组和 24 m min-1 组相比，8 m min-1 组的聚集蛋白水平升高。此外，24 m min-1 组的 ADAMTS5 水平明显高于对照组。
我们的研究结果表明，持续的低强度有氧运动可抑制关节软骨中分解代谢分子的表达，从而促进合成代谢活性。相反，持续的高强度有氧运动可能通过增强分解代谢过程而破坏软骨稳态。这种二分法强调了需要平衡的运动方案来维持软骨健康。
