title: Use of micro-computed tomography to evaluate the effects of exercise on preventing the degeneration of articular cartilage in tail-suspended rats.
abstract: Space flight has been shown to induce bone loss and muscle atrophy, which could initiate the degeneration of articular cartilage. Countermeasures to prevent bone loss and muscle atrophy have been explored, but few spaceflight or ground-based studies have focused on the effects on cartilage degeneration. In this study, we investigated the effects of exercise on articular cartilage deterioration in tail-suspended rats. Thirty-two female Sprague-Dawley rats were randomly divided into four groups (n=8 in each): tail suspension (TS), tail suspension plus passive motion (TSP), tail suspension plus active exercise (TSA), and control (CON) groups. In the TS, TSP, and TSA groups, the rat hindlimbs were unloaded for 21 days by tail suspension. Next, the cartilage thickness and volume, and the attenuation coefficient of the distal femur were evaluated by micro-computed tomography (μCT). Histological analysis was used to assess the surface integrity of the cartilage, cartilage thickness, and chondrocytes. The results showed that: (1) the cartilage thickness on the distal femur was significantly lower in the TS and TSP groups compared with the CON and TSA groups; (2) the cartilage volume in the TS group was significantly lower compared with the CON, TSA, and TSP groups; and (3) histomorphology showed that the chondrocytes formed clusters where the degree of matrix staining was lower in the TS and TSP groups. There were no significant differences between any of these parameters in the CON and TSA groups. The cartilage thickness measurements obtained by μCT and histomorphology correlated well. In general, tail suspension could induce articular cartilage degeneration, but active exercise was effective in preventing this degeneration in tail-suspended rats.
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing 10010, China; Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China. Electronic address: luan_hq@126.com.
authors.forename: Hui-Qin
authors.initials: HQ
authors.lastname: Luan
authors.affiliation: Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China; International Joint Research Center of Aerospace Biotechnology and Medical Engineering, Ministry of Science and Technology of China, Beijing 100191, China. Electronic address: sunlw@buaa.edu.cn.
authors.forename: Lian-Wen
authors.initials: LW
authors.lastname: Sun
authors.affiliation: Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China; International Joint Research Center of Aerospace Biotechnology and Medical Engineering, Ministry of Science and Technology of China, Beijing 100191, China. Electronic address: huang7554789@163.com.
authors.forename: Yun-Fei
authors.initials: YF
authors.lastname: Huang
authors.affiliation: Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China; International Joint Research Center of Aerospace Biotechnology and Medical Engineering, Ministry of Science and Technology of China, Beijing 100191, China. Electronic address: wxt8866@126.com.
authors.forename: Xin-tong
authors.initials: XT
authors.lastname: Wu
authors.affiliation: Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China; International Joint Research Center of Aerospace Biotechnology and Medical Engineering, Ministry of Science and Technology of China, Beijing 100191, China. Electronic address: hjniu@buaa.edu.cn.
authors.forename: Haijun
authors.initials: H
authors.lastname: Niu
authors.affiliation: Department of Sports, Dalian University of Finance and Economics, Dalian 116025, China. Electronic address: liuhong1207@163.com.
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.affiliation: Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China; International Joint Research Center of Aerospace Biotechnology and Medical Engineering, Ministry of Science and Technology of China, Beijing 100191, China. Electronic address: yubofan@buaa.edu.cn.
authors.forename: Yu-Bo
authors.initials: YB
authors.lastname: Fan
mesh_terms: D000818:Animals; D015519:Bone Density / Q000502:physiology; D001862:Bone Resorption / Q000473:pathology; D002358:Cartilage, Articular / Q000473:pathology*; D005260:Female; D005269:Femur / Q000473:pathology*; D019417:Hindlimb Suspension / Q000009:adverse effects*; D018482:Muscle, Skeletal / Q000473:pathology*; D009133:Muscular Atrophy / Q000473:pathology* / Q000517:prevention & control*; D010805:Physical Conditioning, Animal / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013026:Space Flight; D014893:Weightlessness / Q000009:adverse effects; D055114:X-Ray Microtomography
keywords: Articular cartilage; Exercise; Histomorphology; Micro-computed tomography; Unloading