Juglanin inhibits IL-1β-induced inflammation in human chondrocytes

Osteoarthritis (OA) is one of the most characterized joint diseases associated with chondrocyte apoptosis. Juglanin has been reported to have anti-inflammation activity. This study aimed to evaluate the protective anti-inflammatory effects of juglanin in human OA chondrocytes. Human OA chondrocytes were pretreated with juglanin (10, 20 and 40 μM) for 2 h and subsequently stimulated with IL-1β for 24 h. Nitric oxide (NO) production was determined using the Griess method and prostaglandin E2 (PGE2), matrix metalloproteinase-3, -9 and -13 (MMP-3, MMP-9 and MMP-13), TNF-α, and IL-6 were assessed using ELISA. The expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), a disintegrin and metalloproteinase with thrombospondin motifs-4 and -5 (ADAMTS-4 and ADAMTS-5) were detected by qRT-PCR and western blot analysis. NF-κB signalling molecules were detected by western blot analysis. The results showed that juglanin dose-dependently suppressed PGE2, NO, MMP-1, MMP3, MMP13, TNF-α and IL-6 production induced by IL-1β. The expression of COX-2, iNOS, ADAMTS-4 and ADAMTS-5 induced by IL-1β were also suppressed by juglanin pretreatment. Western blot analysis showed that juglanin suppressed IL-1β-induced NF-κB activation. Taken together, we found that juglanin inhibits IL-1β-induced inflammation through the regulation of NF-κB signalling. Juglanin might be used as a therapeutic agent for treating OA.