title: Effect of daily short-duration weight-bearing on disuse-induced deterioration of musculoskeletal system.
abstract: OBJECTIVE
  To investigate deterioration of musculoskeletal system due to prolonged disuse and the potential of daily short-duration weight-bearing as countermeasures.
  
  
  METHODS
  Twenty-four adult male Sprague-Dawley rats were divided into Control Group (CG, no intervention), Tail-suspension Group (TG, tail-suspension without treatment), and Weight-Bearing Group (WBG, tail-suspension with 20 min/day, 5 days/week body weight loading). After four weeks of treatment, femur and tibia, soleus and extensor digitorum longus were evaluated for bone and muscle quality respectively. Tensile properties of bone-tendon insertion (BTI) were evaluated using patella-patellar tendon complex.
  
  
  RESULTS
  Disuse induced deterioration on bone, muscle, and BTI after four weeks. Compared with CG, TG and WBG showed significant decrease in bone mineral density (BMD) of trabecular bone in distal femur (4.3-15.2%), muscle mass (31.3-52.3%), muscle cross-sectional area (29.1-35%), and failure strength of BTI (23.9-29.4%). Tensile test showed that the failure mode was avulsion of bone at the BTI. No significant difference was detected between TG and WBG for all assessments on bone, muscle, and BTI.
  
  
  CONCLUSIONS
  Disuse caused deterioration of bone, muscle, and BTI while daily short-duration of weight-bearing did not prevent this deterioration. Mechanical stimulation with higher intensity and longer duration may be necessary to prevent musculoskeletal deterioration resulted from prolonged disuse.
authors.affiliation: Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, PR China.
authors.forename: K-S
authors.initials: KS
authors.lastname: Leung
authors.affiliation: State key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, PR China.
authors.forename: Y-H
authors.initials: YH
authors.lastname: Li
authors.affiliation: State key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, PR China.
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, PR China.
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.affiliation: Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, PR China.
authors.forename: K-F
authors.initials: KF
authors.lastname: Tam
authors.affiliation: Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, PR China.
authors.forename: D Hk
authors.initials: DH
authors.lastname: Chow
authors.affiliation: State key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, PR China.
authors.forename: Y
authors.initials: Y
authors.lastname: Wan
authors.affiliation: State key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, PR China.
authors.forename: S
authors.initials: S
authors.lastname: Ling
authors.affiliation: State key Lab of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, PR China.
authors.forename: Z
authors.initials: Z
authors.lastname: Dai
authors.affiliation: Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, PR China.|The CUHK-ACC Space Medicine Centre on Health Maintenance of Musculoskeletal System, The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, PR China.
authors.forename: L
authors.initials: L
authors.lastname: Qin
authors.affiliation: Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, PR China.
authors.forename: W-H
authors.initials: WH
authors.lastname: Cheung
mesh_terms: D019412:Anatomy, Cross-Sectional; D000818:Animals; D015519:Bone Density; D005269:Femur / Q000473:pathology; D019417:Hindlimb Suspension; D008297:Male; D018482:Muscle, Skeletal / Q000473:pathology; D020966:Muscular Disorders, Atrophic / Q000473:pathology*; D009141:Musculoskeletal System / Q000473:pathology*; D017847:Patellar Ligament / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D055070:Resistance Training / Q000379:methods*; D013718:Tensile Strength; D013977:Tibia / Q000473:pathology; D014057:Tomography, X-Ray Computed