title: Repeated exposure to high-frequency low-amplitude vibration induces degeneration of murine intervertebral discs and knee joints.
abstract: OBJECTIVE
  High-frequency, low-amplitude whole-body vibration (WBV) is being used to treat a range of musculoskeletal disorders; however, there is surprisingly limited knowledge regarding its effect(s) on joint tissues. This study was undertaken to examine the effects of repeated exposure to WBV on bone and joint tissues in an in vivo mouse model.
  
  
  METHODS
  Ten-week-old male mice were exposed to vertical sinusoidal vibration under conditions that mimic those used clinically in humans (30 minutes per day, 5 days per week, at 45 Hz with peak acceleration at 0.3g). Following WBV, skeletal tissues were examined by micro-computed tomography, histologic analysis, and immunohistochemistry, and gene expression was quantified using real-time polymerase chain reaction.
  
  
  RESULTS
  Following 4 weeks of WBV, intervertebral discs showed histologic hallmarks of degeneration in the annulus fibrosus, disruption of collagen organization, and increased cell death. Greater Mmp3 expression in the intervertebral disc, accompanied by enhanced collagen and aggrecan degradation, was found in mice exposed to WBV as compared to controls. Examination of the knee joints after 4 weeks of WBV revealed meniscal tears and focal damage to the articular cartilage, changes resembling osteoarthritis. Moreover, mice exposed to WBV also demonstrated greater Mmp13 gene expression and enhanced matrix metalloproteinase-mediated collagen and aggrecan degradation in articular cartilage as compared to controls. No changes in trabecular bone microarchitecture or density were detected in the proximal tibia.
  
  
  CONCLUSIONS
  Our experiments reveal significant negative effects of WBV on joint tissues in a mouse model. These findings suggest the need for future studies of the effects of WBV on joint health in humans.
authors.affiliation: University of Western Ontario Schulich School of Medicine and Dentistry, London, Ontario, Canada.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: McCann
authors.affiliation: University of Western Ontario Schulich School of Medicine and Dentistry, London, Ontario, Canada.
authors.forename: Priya
authors.initials: P
authors.lastname: Patel
authors.affiliation: University of Western Ontario Schulich School of Medicine and Dentistry, London, Ontario, Canada.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Pest
authors.affiliation: University of Western Ontario Schulich School of Medicine and Dentistry, London, Ontario, Canada.
authors.forename: Anusha
authors.initials: A
authors.lastname: Ratneswaran
authors.affiliation: University of Western Ontario Schulich School of Medicine and Dentistry, London, Ontario, Canada.
authors.forename: Gurkeet
authors.initials: G
authors.lastname: Lalli
authors.affiliation: University of Western Ontario Schulich School of Medicine and Dentistry, London, Ontario, Canada.
authors.forename: Kim L
authors.initials: KL
authors.lastname: Beaucage
authors.affiliation: University of Western Ontario Schulich School of Medicine and Dentistry, London, Ontario, Canada.
authors.forename: Garth B
authors.initials: GB
authors.lastname: Backler
authors.affiliation: University of Western Ontario Schulich School of Medicine and Dentistry, London, Ontario, Canada.
authors.forename: Meg P
authors.initials: MP
authors.lastname: Kamphuis
authors.affiliation: University of Western Ontario Schulich School of Medicine and Dentistry, London, Ontario, Canada.
authors.forename: Ziana
authors.initials: Z
authors.lastname: Esmail
authors.affiliation: University of Western Ontario Schulich School of Medicine and Dentistry, London, Ontario, Canada.
authors.forename: Jimin
authors.initials: J
authors.lastname: Lee
authors.affiliation: University of Western Ontario Schulich School of Medicine and Dentistry, London, Ontario, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Barbalinardo
authors.affiliation: Shriners Hospital for Children and McGill University, Montreal, Quebec, Canada.
authors.forename: John S
authors.initials: JS
authors.lastname: Mort
authors.affiliation: Robarts Research Institute and University of Western Ontario, Schulich School of Medicine and Dentistry, London, Ontario, Canada.
authors.forename: David W
authors.initials: DW
authors.lastname: Holdsworth
authors.affiliation: University of Western Ontario Schulich School of Medicine and Dentistry, London, Ontario, Canada.
authors.forename: Frank
authors.initials: F
authors.lastname: Beier
authors.affiliation: University of Western Ontario Schulich School of Medicine and Dentistry, London, Ontario, Canada.
authors.forename: S Jeffrey
authors.initials: SJ
authors.lastname: Dixon
authors.affiliation: University of Western Ontario Schulich School of Medicine and Dentistry, London, Ontario, Canada.
authors.forename: Cheryle A
authors.initials: CA
authors.lastname: Séguin
mesh_terms: D053674:Aggrecans / Q000378:metabolism; D000818:Animals; D015519:Bone Density; D002358:Cartilage, Articular / Q000293:injuries* / Q000378:metabolism / Q000473:pathology; D003094:Collagen / Q000378:metabolism; D020869:Gene Expression Profiling; D007403:Intervertebral Disc / Q000293:injuries* / Q000378:metabolism / Q000473:pathology; D007869:Leg Injuries / Q000175:diagnosis / Q000209:etiology* / Q000378:metabolism; D008297:Male; D053509:Matrix Metalloproteinase 13 / Q000378:metabolism; D019278:Matrix Metalloproteinase 3 / Q000378:metabolism; D008592:Menisci, Tibial / Q000378:metabolism / Q000473:pathology; D051379:Mice; D012333:RNA, Messenger / Q000378:metabolism*; D011859:Radiography; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013124:Spinal Injuries / Q000175:diagnosis / Q000209:etiology* / Q000378:metabolism; D013977:Tibia / Q000000981:diagnostic imaging / Q000293:injuries*; D000070600:Tibial Meniscus Injuries; D014732:Vibration / Q000009:adverse effects*
chemical_list: D053674:Aggrecans; D012333:RNA, Messenger; D003094:Collagen; D053509:Matrix Metalloproteinase 13; C507081:Mmp13 protein, mouse; D019278:Matrix Metalloproteinase 3; C511769:Mmp3 protein, mouse