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Pain Research and Treatment
Volume 2012 (2012), Article ID 127636, 11 pages
http://dx.doi.org/10.1155/2012/127636
Research Article

Lumbar Facet Joint Compressive Injury Induces Lasting Changes in Local Structure, Nociceptive Scores, and Inflammatory Mediators in a Novel Rat Model

1Department of Psychiatry and Behavioural Neurosciences, McMaster University, HSC 4N35, 1200 Main Street West, Hamilton, ON, Canada L8N 3Z5
2Division of Research, Canadian Memorial Chiropractic College, 6100 Leslie Street, Toronto, ON, Canada M2H 3J1
3Department of Biochemistry, Rush University Medical Center, Cohn Research BD 516, 1735 W. Harrison, Chicago, IL 60612, USA
4Section of Rheumatology, Department of Internal Medicine, Rush University Medical Center, Cohn Research BD 516, 1735 W. Harrison, Chicago, IL 60612, USA
5Department of Orthopedic Surgery, Rush University Medical Center, Cohn Research BD 516, 1735 W. Harrison, Chicago, IL 60612, USA

Received 30 January 2012; Accepted 9 April 2012

Academic Editor: Howard Smith

Copyright © 2012 James L. Henry et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objective. To develop a novel animal model of persisting lumbar facet joint pain. Methods. Sprague Dawley rats were anaesthetized and the right lumbar (L5/L6) facet joint was exposed and compressed to ~1 mm with modified clamps applied for three minutes; sham-operated and naïve animals were used as control groups. After five days, animals were tested for hind-paw sensitivity using von Frey filaments and axial deep tissue sensitivity by algometer on assigned days up to 28 days. Animals were sacrificed at selected times for histological and biochemical analysis. Results. Histological sections revealed site-specific loss of cartilage in model animals only. Tactile hypersensitivity was observed for the ipsi- and contralateral paws lasting 28 days. The threshold at which deep tissue pressure just elicited vocalization was obtained at three lumbar levels; sensitivity at . Biochemical analyses revealed increases in proinflammatory cytokines, especially TNF-α, IL-1α, and IL-1β. Conclusions. These data suggest that compression of a facet joint induces a novel model of local cartilage loss accompanied by increased sensitivity to mechanical stimuli and by increases in inflammatory mediators. This new model may be useful for studies on mechanisms and treatment of lumbar facet joint pain and osteoarthritis.