Berberine inhibits the interleukin-1 beta-induced inflammatory response via MAPK downregulation in rat articular chondrocytes.

Osteoarthritis (OA) is one of the most chronic degenerative arthritic diseases, which gradually results in chondrocyte changes, articular cartilage degeneration, subchondral bone sclerosis, joint pain, swelling, and dysfunction. Berberine (BBR) has various confirmed biological activities, such as anti-inflammatory and antioxidant activities. However, the effect of BBR on the production of inflammation-associated proteins, including inducible nitric oxide synthase (iNOS), cyclooxygenase (Cox)-2, metalloproteinases (MMPs), Collagen II, TNF-α, and IL-6 via the MAPK (mitogen-activated protein kinases) pathway in IL-1β-stimulated rat chondrocytes, has not yet been studied. Thus, the purpose of this study was to evaluate whether BBR would decrease the production of inflammation-associated proteins through the MAPK signal pathway. Rat chondrocytes were cultured and pretreated with BBR at different concentrations (0, 25, 50, and 100 μM) and then stimulated with or without IL-1β (10 ng/mL). The mRNA expression of iNOS, COX-2, MMP-3, MMP-13, TNF-α, and IL-6 was measured by real-time polymerase chain reaction (RT-PCR), and the protein expression of iNOS, COX-2, Collagen II, MMP-3,MMP-13, and MAPKs were measured by Western blotting. The results showed that the expression of iNOS, COX-2, MMP-3, MMP-13, TNF-α, and IL-6 increased in the IL-1β-treated group and BBR showed an ability to inhibit the elevated expression under the pretreatment. Furthermore, the IL-1β-induced downregulation of Collagen II could be ameliorated by BBR. Moreover, the expression of MAPKs was significantly decreased by BBR. These results demonstrated that BBR had the anti-catabolic and anti-inflammation abilities that were through the MAPKs in IL-1β-induced rat chondrocytes. These findings may provide a novel therapeutic choice for treatment of OA using BBR.