Increased Chondroprotective Effect of Combining Hyaluronic Acid with a Glucocorticoid Compared to Separate Administration on Cytokine-Treated Osteoarthritic Chondrocytes in a 2D Culture

Intra-articular injections of glucocorticoids (GC) or hyaluronic acid (HA) are commonly used interventions for patients suffering from knee osteoarthritis (OA). Both substances are combined to achieve a chondroprotective and anti-inflammatory effect. Clinical studies have shown benefits, but data on the cellular level are still lacking. This study aimed to investigate the effect of the GC triamcinolone hexacetonide, HA, and a mix of both substances on cytokine-treated chondrocytes in vitro. Chondrocytes isolated from human articular cartilage were seeded on 6- and 24-well plates. Mimicking OA's inflammatory state, cells were treated with IL-1β and IL-17 for six days, whereby, after three days, test substances (10%) were added to the culture medium. Chondrocytes were analyzed on days three and six concerning their actin polymerization, expression of anabolic and catabolic genes, metabolic activity, cytokine release, and reactive oxygen species (ROS). Adding HA or GC/HA to the inflammatory culture medium increased the metabolic activity of chondrocytes, while groups containing GC reduced catabolic gene expression and the release of TNF-α. In addition, enhanced F-actin content was shown supplementing HA or GC/HA to the culture medium. Supplementing GC with HA leads to an anti-inflammatory and chondroprotective effect by diminishing the side effects of GC supplementation alone.