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Lookup NU author(s): Jenny Scott, Christos Gavriilidis, Emeritus Professor Thomas Kirkwood, Professor Robert Taylor, Professor David YoungORCiD
Background Oxidative stress is proposed as an important factor in osteoarthritis (OA). Objective To investigate the expression of the three superoxide dismutase (SOD) antioxidant enzymes in OA. Methods SOD expression was determined by real-time PCR and immunohistochemistry using human femoral head cartilage. SOD2 expression in Dunkin-Hartley guinea pig knee articular cartilage was determined by immunohistochemistry. The DNA methylation status of the SOD2 promoter was determined using bisulphite sequencing. RNA interference was used to determine the consequence of SOD2 depletion on the levels of reactive oxygen species (ROS) using MitoSOX and collagenases, matrix metalloproteinase 1 (MMP-1) and MMP-13, gene expression. Results All three SOD were abundantly expressed in human cartilage but were markedly downregulated in end-stage OA cartilage, especially SOD2. In the Dunkin-Hartley guinea pig spontaneous OA model, SOD2 expression was decreased in the medial tibial condyle cartilage before, and after, the development of OA-like lesions. The SOD2 promoter had significant DNA methylation alterations in OA cartilage. Depletion of SOD2 in chondrocytes increased ROS but decreased collagenase expression. Conclusion This is the first comprehensive expression profile of all SOD genes in cartilage and, importantly, using an animal model, it has been shown that a reduction in SOD2 is associated with the earliest stages of OA. A decrease in SOD2 was found to be associated with an increase in ROS but a reduction of collagenase gene expression, demonstrating the complexities of ROS function.
Author(s): Scott JL, Gabrielides C, Davidson RK, Swingler TE, Clark IM, Wallis GA, Boot-Handford RP, Kirkwood TBL, Talyor RW, Young DA
Publication type: Article
Publication status: Published
Journal: Annals of the Rheumatic Diseases
Year: 2010
Volume: 69
Issue: 8
Pages: 1502-1510
Print publication date: 01/08/2010
Date deposited: 19/08/2010
ISSN (print): 0003-4967
ISSN (electronic): 1468-2060
Publisher: BMJ Publishing Group
URL: http://dx.doi.org/10.1136/ard.2009.119966
DOI: 10.1136/ard.2009.119966
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