Caffeic acid alleviates osteoarthritis progression by suppressing ferroptosis-associated injury and modulating the ACSL4-GPX4 axis
Abstract
Background: This study explores the protective effects of caffeic acid (CA) on chondrocytes and its mechanisms in mitigating osteoarthritis (OA) progression. Methods: We investigated the effects of CA on OA progression in a monosodium iodoacetate (MIA)-induced rat OA model and IL-1β/Erastin-stimulated C28/I2 chondrocytes using behavioral testing, histological analysis, cell viability assays, enzyme-linked immunosorbent assay (ELISA) for pro-inflammatory cytokines, ferroptosis marker detection, and western blotting. Results: In vivo , CA (20 mg/kg, oral) was tested in a rat OA model induced by MIA. Behavioral tests showed that CA restored hindlimb grip strength and improved locomotor activity in OA rats. Histological analysis (HE, Safranin O-Fast Green, Toluidine Blue) revealed that CA attenuated cartilage degradation, reduced proteoglycan loss, and lowered OARSI scores. In vitro , CA (10/20 μM) pretreatment improved cell viability (CCK-8) in IL-1β-challenged C28/I2 chondrocytes, and modulated ferroptosis-related phenotypes in cells stimulated with Erastin (a canonical ferroptosis inducer). ELISA results demonstrated that CA dose-dependently decreased the secretion of IL-6 and TNF-α in IL-1β-challenged chondrocytes, reflecting a significant anti-inflammatory effect. Additionally, CA-treated cells showed reduced iron overload (FerroOrange), decreased ROS accumulation (DCFH-DA), and restored mitochondrial function (MitoTracker Red/JC-1). Western blot analysis demonstrated that CA upregulated Collagen II, GPX4, and SLC7A11 while downregulating MMP13 and ACSL4, suggesting modulation of ferroptosis and extracellular matrix (ECM) stability. Conclusion: These findings indicate that CA ameliorates OA-related cartilage damage and preserves ECM integrity, accompanied by altered expression of key ferroptosis-related molecules including ACSL4, GPX4 and SLC7A11. The observed chondroprotective effect of CA may be linked to ferroptosis modulation, with potential involvement of ACSL4-GPX4-associated signaling. Collectively, our data suggest CA is a promising candidate for OA pharmacotherapy, supporting further preclinical and clinical validation.