Cyclical articular joint loading leads to cartilage thinning and osteopontin production in a novel in vivo rabbit model of repetitive finger flexion.
Authors
King-KB; Opel-CF; Rempel-DM
Source
Osteoarthr Cartil 2005 Nov; 13(11):971-978
Abstract
An in vivo rabbit model of repetitive joint flexion and loading was used to characterize the morphological effects of cyclical loading on articular cartilage. The forepaw digits of eight anesthetized New Zealand White adult female rabbits were repetitively flexed at 1 Hz with a mean peak digit load of 0.42 N for 2 h per day for 60 cumulative hours. Metacarpophalangeal joints were collected from loaded and contra-lateral control limbs, fixed, decalcified, embedded, and thin-sectioned. Serial sections were stained for histology or for immunohistochemistry. Morphometric data including the mean thicknesses of the uncalcified cartilage and of the calcified cartilage were collected from digital photomicrographs of safranin O-stained sections. The number of cells stained with anti-osteopontin antibody was counted. We observed a decrease in uncalcified cartilage mean thickness with no significant change in calcified cartilage thickness. We also observed a significant increase in the number of cells positive for osteopontin (OPN) in the uncalcified cartilage. These changes occurred without overt cartilage surface degeneration. Cyclical loading leads to changes at the tissue and cellular levels in articular cartilage. These changes are suggestive of tidemark advancement and may indicate a reactivation of cartilage mineralization steps analogous to endochondral ossification. This novel in vivo rabbit model of repetitive flexion and loading can be used to investigate the effects of cyclical loading on articular joints.
Keywords
Laboratory-animals; Animals; Animal-studies; In-vivo-study; Models; Repetitive-work; Morphology
Contact
Karen B. King, Ph.D., University of California, Ergonomics Program, 1301 South 46th Street, Building 163, Richmond, CA 94804
Document Type
Journal Article
Email Address
kbking@itsa.ucsf.edu
Identifying No.
Grant-Number-R01-OH-007786
Priority Area
Disease and Injury: Musculoskeletal Disorders of the Upper Extremities
Source Name
Osteoarthritis and Cartilage
Performing Organization
University of Colorado, Denver
