Ozone Kaichi, Oka Yuichiro, Minegishi Yuki, Kano Takuma, Kokubun Takanori, Murata Kenji, Kanemura Naohiko
Graduate Course of Health and Social Services, Graduate School of Saitama Prefectural University, Saitama 343-8540, Japan.
Research Fellowship for Young Scientists, Japan Society for the Promotion of Science, Tokyo 102-0083, Japan.
Life (Basel). 2021 Mar 27;11(4):284. doi: 10.3390/life11040284.
How various types of muscle contraction during exercises affect bone formation remains unclear. This study aimed to determine how exercises with different muscle contraction types affect bone morphology. In total, 20 mice were used and divided into four groups: Control, Level, Down Slow, and Down. Different types of muscle contraction were induced by changing the running angle of the treadmill. After the intervention, micro-computed tomography (Micro-CT), tartrate-resistant acid phosphatase/alkaline phosphatase (ALP) staining, and immunohistochemical staining were used to analyze the humerus head, tendon-to-bone attachment, and humerus diaphyseal region. Micro-CT found that the volume ratio of the humeral head, the volume of the tendon-to-bone attachment region, and the area of the humeral diaphyseal region increased in the Down group. However, no difference was detected in bone morphology between the Level and Down Slow groups. In addition, histology showed activation of ALP in the subarticular subchondral region in the Down Slow and Down groups and the fibrocartilage region in the tendon-to-bone attachment. Moreover, Osterix increased predominantly in the Down Slow and Down groups.Overall bone morphological changes in the humerus occur only when overuse is added to EC-dominant activity. Furthermore, different type of muscle contractile activities might promote bone formation in a site-specific manner.
运动期间不同类型的肌肉收缩如何影响骨形成仍不清楚。本研究旨在确定不同肌肉收缩类型的运动如何影响骨形态。总共使用了20只小鼠，分为四组：对照组、水平组、慢速下降组和下降组。通过改变跑步机的跑步角度诱导不同类型的肌肉收缩。干预后，使用微型计算机断层扫描（Micro-CT）、抗酒石酸酸性磷酸酶/碱性磷酸酶（ALP）染色和免疫组织化学染色来分析肱骨头、肌腱与骨的附着处以及肱骨干区域。Micro-CT发现，下降组的肱骨头体积比、肌腱与骨附着区域的体积以及肱骨干区域的面积增加。然而，水平组和慢速下降组之间在骨形态上未检测到差异。此外，组织学显示，慢速下降组和下降组的关节下软骨下区域以及肌腱与骨附着处的纤维软骨区域中ALP被激活。此外，Osterix主要在慢速下降组和下降组中增加。只有在以离心收缩为主的活动中增加过度使用时，肱骨才会出现整体骨形态变化。此外，不同类型的肌肉收缩活动可能以位点特异性方式促进骨形成。
