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Objective. To study the effects of a matrix metalloproteinase (MMP) inhibitor (S-34219) on osteoarthritis (OA) cartilage cultures and in the meniscectomized guinea pig model of OA.Methods. The inhibitory activity of S-34219 on MMPs and aggrecanase was studied by fluorimetry and immunoassay, respectively. The effects of S-34219 on proteoglycan and collagen degradation were studied in cultures of rabbit and human cartilage. Medial meniscectomy was performed on 29 Hartley male guinea pigs, and these animals were randomly allocated to 1 of 3 groups: a control meniscectomized group (MNXc) receiving the vehicle, or a meniscectomized group receiving either 10 mg/kg or 20 mg/kg S-34219, administered twice per day by oral gavage for 12 weeks from day 1 after surgery. An additional group comprised shamoperated animals. Tibial cartilage from the operated left knee was processed for histologic assessment of OA lesions.Results. The 50% inhibitory concentration (IC 50 ) of S-34219 on MMPs 1, 2, 3, 8, 9, and 13 was 55, 0.1, 0.5, 0.1, 0.03, and 0.2 nM, respectively; the IC 50 on aggrecanase 1 was 190 nM. In cultured rabbit cartilage, 100 nM S-34219 strongly inhibited MMP-dependent degradation of collagen and proteoglycans. A concentration 100 times higher was needed to inhibit aggrecanasedependent degradation. In cultures of human OA cartilage, 100 nM S-34219 inhibited spontaneous type II collagen degradation by 66% and proteoglycan degradation by only 22%. For in vivo studies, treated groups were compared with the MNXc group and the results, expressed as the percentage variation versus MNXc, were as follows: in the 10 and 20 mg/kg groups, a significant decrease (P < 0.05) in global histologic score (؊12% and ؊14%, respectively) was observed, and this was associated with a significant increase (P < 0.05) in cartilage thickness (؉19% and ؉18%, respectively). Neither dose level changed the proteoglycan content.Conclusion. In both treated animal groups, S-34219 significantly prevented the loss of cartilage thickness, probably by inhibiting collagen breakdown that normally leads to the erosion of fibrillated superficial areas. The absence of a protective effect on glycosaminoglycan loss, both in vitro and in vivo, suggests that aggrecanases may have an important role in cartilage loss. This study reinforces the relevance of these models for testing chondroprotective drugs, and the potential role of dual inhibitors of collagenase and aggrecanase as disease-modifying drugs in the management of OA.Osteoarthritis (OA) is a major joint disease in humans and various animals in which articular cartilage degenerates over a period of time and leads to denudation of the joint surface. This degeneration is mainly characterized by a progressive degradation of extracellular matrix (ECM) components, followed by chondrocyte death, tissue fibrillation, and erosion (1). Metalloproteinases of 2 families seem to play a major role in cartilage ECM breakdown. These are 1) aggrecanases, which, starting at an early stage of disease, specifically degrade ...

TGFbeta stimulates ADAMTS-4 expression and aggrecan degradation in cartilage. This catabolic action seems to be partially mediated by aggrecanases. It is, therefore, proposed that the role of TGFbeta in cartilage matrix turnover is not limited to anabolic and anti-catabolic actions, but also extends to selective degradation of matrix components such as aggrecan.

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A classic method for the encapsulation and culture of chondrocytes in alginate beads is described. Chondrocytes are released from cartilage matrix by collagenase/dispase digestion and mixed with a solution of 1.25% alginic acid until a homogenous suspension is obtained. The suspension is drawn into a syringe and pushed gently through a needle, so that drops fall into a solution of calcium chloride. Beads form instantaneously and further polymerize after 5 min in the calcium chloride solution. Chondrocytes from any species, including human osteoarthritic chondrocytes, can be cultured with this technique. Under these conditions, chondrocytes maintain a high degree of differentiation. Beads can be dissolved by chelation of calcium with EDTA. In this way, chondrocytes can be recovered and further separated from the matrix by centrifugation. Almost all molecular and biochemical techniques, as well as a number of biological assays, are compatible with the culture of chondrocytes in alginate.