Effects of high-molecular-weight hyaluronic acid on inflammatory and matrix-associated responses in a chondrocyte-osteoclast co-culture model.

Authors

Adam Eid, Kavitha Raja, Dineshwary Suresh, Surendra Singh Rawat, Ivan James Prithishkumar, Thomas Nau, Nerissa Naidoo

Published in

Journal of orthopaedic surgery and research. Jul 13, 2026. Epub Jul 13, 2026.

Abstract

Osteoarthritis (OA) is a degenerative joint disorder marked by chronic inflammation, extracellular matrix (ECM) breakdown, and subchondral bone remodeling, ultimately leading to loss of cartilage integrity and joint function. Hyaluronic acid (HA), a key component of synovial fluid, contributes to joint lubrication and has been implicated in the regulation of inflammatory and anabolic processes. High-molecular-weight (HMW) HA (> 1 MDa) is reported to exert anti-inflammatory and matrix-preserving effects; however, its role in multicellular systems remains incompletely understood. In this study, we investigated the effects of HMW HA using an in vitro chondrocyte-osteoclast co-culture model designed to reflect key features of the osteoarthritic microenvironment.
Bone marrow-derived mesenchymal stem cells were differentiated into chondrocytes, while RAW 264.7 macrophages were induced into osteoclast-like cells using M-CSF and RANKL. Cells were co-cultured at a 1:1 ratio and stimulated with lipopolysaccharide (LPS; 1 µg/mL) to induce inflammatory stress, followed by HA treatment (50-500 µg/mL) for 24-48 h. Cell viability, morphology, and TRAP staining were assessed. Expression of inflammatory and matrix-associated markers was analysed by Western blot, qPCR, and ELISA. Cell-cycle distribution and DNA integrity were evaluated using flow cytometry and agarose gel electrophoresis.
LPS exposure reduced metabolic activity, altered morphology, and was associated with increased expression of NF-κB-related inflammatory markers and elevated expression of IL-1β, TNF-α, MMP-13, and ADAMTS-5, alongside reduced COL2A1 and ACAN levels. HA treatment improved metabolic activity and preserved cellular morphology in a concentration-dependent manner, with the most pronounced effects observed at 200-500 µg/mL. HA-treated cultures showed lower levels of inflammatory and catabolic markers together with increased expression of ECM-associated genes. In addition, HA treatment was associated with a more balanced cell-cycle profile and reduced DNA fragmentation.
HMW HA was associated with coordinated modulation of inflammatory and matrix-related markers in an LPS-induced co-culture system. These findings suggest that HA may contribute to maintaining cellular homeostasis under inflammatory conditions in vitro. Further studies are needed to clarify the underlying mechanisms and translational relevance.

PMID:
42443940
Bibliographic data and abstract were imported from PubMed on 14 Jul 2026.

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