Previous clinical studies have reported the clinical effectiveness of non‑animal stabilized hyaluronic acid (NASHA) and adipose‑derived mesenchymal stromal/stem cells (MSC) in the treatment of knee osteoarthritis (OA). Unlike MSC secreted mediators, in vitro anti‑inflammatory effects of NASHA have not been evaluated. We aimed to evaluate and compare the anti‑inflammatory effect of NASHA and MSC conditioned medium (stem cell‑conditioned medium; SC‑CM), in an explant‑based coculture model of OA. Cartilage and synovial membrane from seven patients undergoing total knee arthroplasty were used to create a coculture system. Recombinant IL‑1β was added to the cocultures to induce inflammation. Four experimental groups were generated: i) Basal; ii) IL‑1β; iii) NASHA (NASHA + IL‑1β); and iv) SC‑CM (SC‑CM + IL‑1β). Glycosaminoglycans (GAG) released in the culture medium and of nitric oxide (NO) production were quantified. Gene expression in cartilage and synovium of IL‑1β, matrix metallopeptidase 13 (MMP13), ADAM metallopeptidase with thrombospondin type 1 motif 5 (ADAMTS5) and tissue inhibitor of metalloproteinases 1 (TIMP1) was measured by reverse transcription‑quantitative PCR. Media GAG concentration was decreased in cocultures with NASHA and SC‑CM (48 h, P<0.05; 72 h, P<0.01) compared with IL‑1β. Production of NO was significantly lower only in SC‑CM after 72 h (P<0.01). In cartilage, SC‑CM inhibited the expression of IL‑1β, MMP13 and ADAMTS5, while NASHA had this effect only in MMP13 and ADAMTS5. In synovium, SC‑CM decreased the expression level of MMP13 and ADAMTS5, while NASHA only decreased ADAMTS5 expression. Both NASHA and SC‑CM increased TIMP1 expression in cartilage and synovium. Treatments with NASHA and SC‑CM were shown to be a therapeutic option that may help counteract the catabolism produced by the inflammatory state in knee OA. The anti‑inflammatory mediators produced by MSC promote a lower expression of inflammatory targets in our study model.
Keywords: hyaluronic acid; mesenchymal stem cells; cartilage; synovium; osteoarthritis.