The purpose of the present study was to explore the mechanism of action of the adipokine chemerin in osteoarthritis (OA) by means of an in vitro OA model.
Primary chondrocytes were isolated from normal rats. The chondrocytes were stimulated with interleukin 1 beta (IL-1β, 10 μg/L) to establish a model of induced OA. Chemerin was administered to cells of this model. After culture of the chondrocytes in the presence of chemerin for 48 h, the expression of the genes related to OA occurrence and protection, matrix metalloproteinase-1 (MMP-1), matrix metalloproteinase-3 (MMP-3), and matrix metalloproteinase-13 (MMP-13) was examined. Western blot was then performed to analyze the phosphorylation of the AKT and extracellular signal-regulated kinase (ERK) proteins in chondrocytes.
Stimulation of chondrocytes with IL-1β markedly reduced the proliferative capability of chondrocytes. Chemerin (5 μM) also significantly decreased the proliferative capability of chondrocytes. The combined administration of IL-1β and chemerin induced an even greater reduction in the proliferative capability of chondrocytes. Polymerase chain reaction (PCR) results showed that both IL-1β and chemerin reduced the expression of the protective genes in OA (MMP-1, MMP-3, and MMP-13). Also, the stimulation with IL-1β and chemerin significantly enhanced the phosphorylation of AKT/ERK in chondrocytes.
This adipokine induces changes in the metabolic and proliferative capabilities of chondrocytes by increasing the phosphorylation of AKT/ERK, thereby inducing OA or aggravating the symptoms of OA.