Expression of proinflammatory cytokines in osteoarthritis of the temporomandibular joint

ObjectiveThis study reports the expression of proinflammatory cytokines in temporomandibular joint (TMJ) of patients affected with temporomandibular osteoarthritis (OA).DesignIn twelve OA of the TMJ (OA–TMJ) affected patients and in six healthy volunteer subjects studied as control, the expression of IL1β (interleukin-1β), IL2, IL4, IL5, IL6, IL10, IL12p35, IL12p40, IL17, IFNγ (interferon-gamma), TNFα (tumor necrosis factor-alpha), and TNFβ mRNAs was evaluated. Using quantitative real-time RT-PCR technique, the cytokine levels, reported as Ct (cycle threshold), ΔCt (Ct cytokine − Ct 18S rRNA) and RQ (relative quantification), in patient and control groups were compared.ResultsExpression of IL1β, IL2, IL12p35, IL12p40, IL17, TNFα, TNFβ, and IFNγ mRNAs was significantly higher in patients as compared with controls. In particular, IL12 was the predominant cytokine expressed in patients (IL12p35 RQ = 30.2 and IL12p40 RQ = 29.0). Conversely, IL10 mRNA levels were higher in controls (RQ = 1.8).ConclusionsThese data suggest that not only IL1β, IFNγ, and TNFα but also IL10, IL12, and IL17 are involved in the OA–TMJ pathogenesis. Furthermore, an inflammatory response characterised by the predominant expression of IL12 mRNA and down-regulated expression of IL10 mRNA is associated with the degenerative changes observed in OA–TMJ.