Proinflammatory
cytokine interleukin-1β (IL-1β) stimulates several mediators of cartilage degradation and plays an important role in the pathogenesis of
osteoarthritis (OA).
Honokiol, a low molecular weight natural product isolated from the Magnolia officinalis, has been shown to possess anti-inflammatory effect. Here, we used an in vitro model of cartilage
inflammation to investigate the therapeutic potential of
honokiol in OA. Human OA chondrocytes were cultured and pretreated with
honokiol (2.5-10 µM) with or without IL-1β (10 ng/ml).
Nitric oxide (NO) production was quantified by
Griess reagent.
Prostaglandin (PG)E2 , metalloproteinase-13 (MMP-13), and
interleukin-6 (IL-6) productions were quantified by
enzyme-linked
immunosorbent assay. The expressions of
collagen II,
cyclooxygenase-2 (COX-2),
inducible nitric oxide synthase (iNOS), and nuclear factor κB (NF-κB)-related signaling molecules were determined by Western blotting. Our data showed that IL-1β markedly stimulated the expressions of iNOS and COX-2 and the productions of NO,
PGE2 , and
IL-6, which could be significantly reversed by
honokiol.
Honokiol could also suppress the IL-1β-triggered activation of IKK/IκBα/NF-κB signaling pathway. Moreover,
honokiol significantly inhibited the IL-1β-induced MMP-13 production and
collagen II reduction. Taken together, the present study suggests that
honokiol may have a chondroprotective effect and may be a potential therapeutic choice in the treatment of OA patients.