A novel osteochondral explant model to study bone and cartilage responses to damage in PTOA

Purpose: Osteoarthritis (OA) is a progressive joint disease, which was traditionally associated with degradation of articular cartilage, but now known to affect other tissues including subchondral bone. Indeed, changes in bone have been shown precede the process cartilage and may contribute it. One specific example this presence marrow lesions (BMLs) acute injury, their potential role development post-traumatic osteoarthritis (PTOA). This bone-cartilage cross-talk can be challenging study vivo due its complexity, thus multi-tissue explant model systems are crucial. Traditional osteo-chondral models (femoral head, or cylindrical cored specimens) useful capturing certain aspects limited that damage necessarily created, during isolation. Thus, we used novel model, where no created harvest. Then, experimental introduced by either chemical mechanical means, subsequent effects on tissue status were determined. Methods: First, characterised rat patella (n=12) as an system, initial damage, comparing state-of-the-art femoral head terms baseline viability assays. The both evaluated using biochemical, histological microstructural Then samples subjected individual responses assessed. For explants exposed 10ng/ml IL-1β for 0, 1, 3 7 days. compression at 0.5 Hz, 10 % strain cycles. In cases, Sulfated glycosaminoglycan (sGAG), MMP-13 measured assessment representative while alkaline phosphatase (ALP) assessed response. Furthermore, histomorphometric, immunohistochemical, evaluations each system also carried out. Results: Our results demonstrate patellar excellent ex crosstalk, one does not induce any time We established culture conditions maintain these standard media up 28 days (data shown). sections, haematoxylin eosin show general morphology (Fig. 1C). Rat patellae showed proteoglycan content metabolism markers significantly increased (p<0.05) after treatment when compared controls (Fig.1 A-B). To confirm finding, qualitative immunohistochemical staining chondrocytes expression MMP13 IL-1β. Mechanically compressed decrease compressive moduli from day 2A), suggested remodelling taken place compensatory mechanism repair microdamage. fully validate findings additional parameters need computer tomography (μCT) addition this, increase release observed three mechanically damaged control 2B). Conclusions: summary, Results cross-talk. types. aim project establish recapitulate injury PTOA. involve creation basal surrogate resulted changes. It well has poor reparative overloading catabolic osteochondral tissue. demonstrates crosstalk