Ozone Kaichi, Minegishi Yuki, Oka Yuichiro, Sato Michiaki, Kanemura Naohiko
Department of Health and Social Services, Health and Social Services, Graduate School of Saitama Prefectural University, Koshigaya 343-8540, Japan.
Department of Rehabilitation, University of Tsukuba Hospital, Tsukuba 305-8576, Japan.
Biology (Basel). 2023 Mar 16;12(3):456. doi: 10.3390/biology12030456.
To date, it remains unclear how overuse affects the tendons and entheses at different stages of maturation. Therefore, we evaluated histological and morphological changes in the tendons and entheses in adolescent (4-week-old) and adult mice (8-week-old) by performing flat-land and downhill running exercises. The mice were divided into the Sedentary, High Flat (flat-land high-speed running; concentric-contraction exercise), Low Down (downhill low-speed running; eccentric-contraction exercise), and High Down (downhill high-speed running; eccentric-contraction exercise) groups. Histological changes and inflammatory factor expressions were compared in the entheses and tendons after 4 weeks of exercise. Downhill, but not flat-land high-speed running, induced muscle-tendon complex hypertrophy in both adolescent and adult mice. Histological enthesis changes were induced in both groups during downhill running but were less pronounced in adult mice. Conversely, no significant cell aggregation or fiber orientation changes were observed in the tendon, but increased inflammatory factors were observed in both groups, with significantly higher expression in the tendons of adult mice. Downhill running induced histological and morphological enthesis changes and inflammatory factor increase in the tendons, regardless of running speed variations. These results may help elucidate the pathogenesis of enthesopathy and tendinopathy, which have different pathophysiologies despite having the same pathogenetic factors.
迄今为止，过度使用如何在不同成熟阶段影响肌腱和附着点仍不清楚。因此，我们通过进行平地和下坡跑步运动，评估了青春期（4周龄）和成年小鼠（8周龄）肌腱和附着点的组织学和形态学变化。将小鼠分为久坐组、高平地组（平地高速跑步；向心收缩运动）、低下坡组（下坡低速跑步；离心收缩运动）和高下坡组（下坡高速跑步；离心收缩运动）。运动4周后，比较附着点和肌腱的组织学变化及炎症因子表达。下坡跑步，而非平地高速跑步，在青春期和成年小鼠中均诱导了肌腱-肌肉复合体肥大。下坡跑步期间，两组均出现了组织学附着点变化，但成年小鼠中的变化不太明显。相反，在肌腱中未观察到明显的细胞聚集或纤维方向改变，但两组均观察到炎症因子增加，成年小鼠肌腱中的表达明显更高。无论跑步速度如何变化，下坡跑步均会诱导附着点的组织学和形态学变化以及肌腱中炎症因子增加。这些结果可能有助于阐明附着点病和肌腱病的发病机制，尽管它们具有相同的致病因素，但却有不同的病理生理学。
