Curcuminoids Phospholipid Attenuates Osteoarthritis and Protects Cartilage in a Monosodium Iodoacetate-Induced Rat Model

Background/Objectives: Osteoarthritis is a chronic joint disorder involving the progressive breakdown of articular cartilage, which leads to joint pain and impaired mobility. The present study investigated the effects of curcuminoids phospholipid (CP) on osteoarthritis progression, assessed its cartilage-protective effects, and elucidated the underlying mechanisms. Methods: Male Sprague–Dawley rats were randomly allocated to six experimental groups. One group received an intra-articular saline injection as the normal control (NC), while the remaining five groups were injected with monosodium iodoacetate (MIA) and consisted of an MIA control group (MC), a positive control group treated with celecoxib (PC, 3 mg/kg), and three groups treated with CP (31.25, 62.5, or 125 mg/kg). Results: Compared with the MC group, CP administration significantly improved pain-related behavior, as assessed by weight-bearing measurements. Micro-computed tomography and histological analyses demonstrated that CP administration mitigated subchondral bone erosion and preserved cartilage integrity. Additionally, the CP treatment significantly reduced markers associated with cartilage degradation, including matrix metalloproteinases and cartilage oligomeric matrix proteins; downregulated the expression of matrix-degrading enzymes; and restored aggrecan expression. Serum levels of inflammatory mediators, including nitric oxide; prostaglandin E₂; C-reactive protein; and pro-inflammatory cytokines, including interleukin (IL)-6, tumor necrosis factor (TNF)-α, and IL-1β, were reduced following CP administration. Furthermore, CP decreased the activation of nuclear factor kappa B (NF-κB) signaling. Conclusions: These findings suggest that CP may be a promising functional agent for osteoarthritis, demonstrating beneficial effects on pain-related outcomes and cartilage integrity, potentially mediated by its anti-inflammatory activity.