Conclusion
The proposed cartilage explant model offers encouraging evidence of the therapeutic potential of ASC-derived CM against OA, and it could serve as a convenient ex vivo platform for drug screening.
Methods
4 mm cartilage punches, derived from the femoral heads of patients undergoing total hip replacement, were treated with 10 ng/ml TNFα, 1 ng/ml IL-1β, or a combination of both, over a 3-day period. Analysis of OA-related markers, such as MMP activity, the release of NO and GAGs, and the expression of PTGS2, allowed for the selection of the most effective inflammatory stimulus. Subsequently, explants challenged with TNFα+IL-1β were exposed to CM, consisting of a pool of concentrated supernatants from 72-h cultured ASCs, in order to evaluate its effect on cartilage catabolism and inflammation.
Results
The 3-day treatment with both 10ng/ml TNFα and 1ng/ml IL-1β significantly increased MMP activity and NO release, without affecting GAG release. The addition of CM significantly downregulated the abnormal MMP activity induced by the inflammatory stimuli, while also mildly reducing MMP3, MMP13, and PTGS2 gene expression. Finally, SOX9 and COL2A1 were downregulated by the cytokines, and further decreased by CM.