The STR/ort mouse and its use as a model of osteoarthritis

Objective. Studies have shown the roles of oxidative stress in the pathogenesis of osteoarthritis (OA) and induction of chondrocyte senescence during OA progression. The aim of this study was to examine the potential of a strong free-radical scavenger, watersoluble fullerene (C60), as a protective agent against catabolic stress-induced degeneration of articular cartilage in OA, both in vitro and in vivo.Methods. In the presence or absence of C60 (100 M), human chondrocytes were incubated with interleukin-1␤ (10 ng/ml) or H 2 O 2 (100 M), and chondrocyte activity was analyzed. An animal model of OA was produced in rabbits by resection of the medial meniscus and medial collateral ligament. Rabbits were divided into 5 subgroups: sham operation or treatment with C60 at 0.1 M, 1 M, 10 M, or 40 M. The left knee joint was injected intraarticularly with watersoluble C60 (2 ml), while, as a control, the right knee joint received 50% polyethylene glycol (2 ml), once weekly for 4 weeks or 8 weeks. Knee bone and cartilage tissue were prepared for histologic analysis. In addition, in the OA rabbit model, the effect of C60 (10 M) on degeneration of articular cartilage was compared with that of sodium hyaluronate (HA) (5 mg/ml).Results. C60 (100 M) inhibited the catabolic stress-induced production of matrix-degrading enzymes (matrix metalloproteinases 1, 3, and 13), downregulation of matrix production, and apoptosis and premature senescence in human chondrocytes in vitro.In rabbits with OA, treatment with water-soluble C60 significantly reduced articular cartilage degeneration, whereas control knee joints showed progression of cartilage degeneration with time. This inhibitory effect was dose dependent, and was superior to that of HA. Combined treatment with C60 and HA yielded a significant reduction in cartilage degeneration compared with either treatment alone. Conclusion.The results indicate that C60 fullerene is a potential therapeutic agent for the protection of articular cartilage against progression of OA.During the development of osteoarthritis (OA), mechanical and chemical stresses on articular cartilage change the stable cellular activities of chondrocytes and stimulate the production of growth factors and matrix proteins as well as inflammation mediators (1-4). It is well known that catabolic-stressed chondrocytes produce excess amounts of reactive oxygen species (ROS) (superoxide, nitric oxide, hydrogen peroxide, and peroxynitrite) as well as proinflammatory cytokines and chemokines (4-9).Studies have provided ample confirmation of the generation of ROS and the depletion of cellular antioxidants in degenerated articular cartilage (8-10). Numerous reports have indicated that the degeneration of articular cartilage is partially mediated by oxygenderived free radicals (8-12). Kurz et al reported that the extent of mechanical stress on articular cartilage is sufficient to stimulate an excess production of ROS from chondrocytes, leading to depolymerization of hyaluronic acid and chondrocyte death (11,12). Similarly, Gree...

Section: Discussionmentioning

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Water‐soluble C60 fullerene prevents degeneration of articular cartilage in osteoarthritis via down‐regulation of chondrocyte catabolic activity and inhibition of cartilage degeneration during disease development

Yudoh

Shishido

Murayama

et al. 2007

“…Spontaneous OA cartilage destruction in STR/Ort mice was examined at age 28 weeks (21,24). Experimental OA was induced by destabilization of the medial meniscus (DMM) surgery or by intraarticular injection of 1 ϫ 10 9 plaque-forming units (PFU) of mouse Dkk1-expressing adenovirus (AdDkk-1) in 10-12-week-old male mice (21,25).…”

Section: Methodsmentioning

confidence: 99%

Dkk‐1 expression in chondrocytes inhibits experimental osteoarthritic cartilage destruction in mice

Oh¹,

Chun²,

Chun³

2012

108

Objective. Dkk is a family of canonical Wnt antagonists with 4 members (Dkk-1, Dkk-2, Dkk-3, and Dkk-4). We undertook this study to explore the roles of Dkk-1 and Dkk-2 in osteoarthritic (OA) cartilage destruction in mice.Methods. Expression of Dkk and other catabolic factors was determined at the messenger RNA and protein levels in human and mouse OA cartilage. Experimental OA in mice was induced by destabilization of the medial meniscus (DMM) or by intraarticular injection of Epas1 adenovirus (AdEPAS-1). The role of Dkk in OA pathogenesis was examined by intraarticular injection of AdDkk-1 or by using chondrocyte-specific Dkk1 (Col2a1-Dkk1)-transgenic mice and Dkk2 (Col2a1-Dkk2)-transgenic mice. Primary culture mouse chondrocytes were also treated with recombinant Dkk proteins.Results. We found opposite patterns of Dkk1 and Dkk2 expression in human and mouse experimental OA cartilage: Dkk1 was up-regulated and Dkk2 was downregulated. Overexpression of Dkk1 by intraarticular injection of AdDkk-1 significantly inhibited DMMinduced experimental OA. DMM-induced OA was also significantly inhibited in Col2a1-Dkk1-transgenic mice compared with their wild-type littermates. However, Col2a1-Dkk2-transgenic mice showed no significant difference in OA pathogenesis. Wnt-3a, which activates the canonical Wnt pathway, induced Mmp13 and Adamts4 expression in primary culture chondrocytes, an effect that was significantly inhibited by Dkk-1 pretreatment or Dkk1 overexpression.Conclusion. Our findings indicate that expression of Dkk1, but not Dkk2, in chondrocytes inhibits OA cartilage destruction. The protective effect of Dkk-1 appears to be associated with its capacity to inhibit Wnt-mediated expression of catabolic factors, such as Mmp13, providing evidence that Dkk-1 might serve as a therapeutic target for OA treatment.

“…A colony of STR/Ort mice was established from 3 original breeding pairs obtained from Dr. R. M. Mason (Imperial College of Medicine, London, UK) (25). The joints from both hind limbs were collected from 3 groups of male STR/Ort mice at 3, 9, and 12 months of age.…”

Section: Methodsmentioning

confidence: 99%

“…STR/Ort animals spontaneously develop histologic lesions resembling those of human OA, with ϳ85% of male STR/Ort mice developing the disease in the medial tibial plateau at age 1 year (25). Using genomewide expression profiling and functional analysis, development and function of the connective tissue and lipid metabolism were shown to be the biologic functions that are most significantly up-regulated and down-regulated, respectively, during OA progression.…”

mentioning

confidence: 99%

Inverse relationship between matrix remodeling and lipid metabolism during osteoarthritis progression in the STR/ORT mouse

Watters¹,

Cheng²,

Pickarski³

et al. 2007

Objective. The biologic changes associated with osteoarthritis (OA) are incompletely understood. The aim of this study was to elucidate the molecular mechanisms underlying OA progression in an STR/Ort murine model of spontaneous disease.Methods. Global patterns of gene expression were assessed using microarray analysis of articular cartilage/subchondral bone from the tibial plateaus of STR/Ort mice at 3, 9, and 12 months of age. The age-dependent severity of osteophyte formation and extent of cartilage damage were determined in the corresponding femurs using microfocal computed tomography and the Mankin histologic scoring system. Pathway analysis was used to identify the functions of genes associated with OA progression, and changes in gene expression were confirmed using immunohistochemistry.Results. Six hundred twenty-one genes were associated with both osteophyte formation and cartilage damage in the STR/Ort joints. Genes involved in the development/function of connective tissue and in lipid metabolism were most significantly enriched and regulated during disease progression. Genes directly interacting with peroxisome proliferator-activated receptor ␣ (PPAR␣)/PPAR␥ were down-regulated, whereas those genes involved with connective tissue remodeling were up-regulated during disease progression. Associations of down-regulation of myotubularinrelated phosphatase 1 (a phosphoinositide 3-phosphatase involved in lipid signaling) and up-regulation of biglycan (a member of the small leucine-rich protein family known to modulate osteoblast differentiation and matrix mineralization) with OA progression were confirmed by immunohistochemistry.Conclusion. Since adipogenesis and osteogenesis are inversely related in the developing skeletal tissue, these results suggest that a shift in the differentiation of mesenchymal cells from adipogenesis toward osteogenesis is a component of the OA pathophysiologic processes occurring in the tibial plateau joints of STR/Ort mice.