Therapeutic Effect of the Quinolone Levofloxacin on Inflammatory Fibroblast-like Synoviocytes.

This study aims to analyze the effects of quinolones on synovium. The present study explored the effects of levofloxacin on fibroblast-like synoviocyte (FLS) in vitro. After incubation with 10 ng/mL of interleukin-1β (IL-1β) for 24 hours, rabbit FLS were treated with serial concentrations of levofloxacin (0,14,28,56,112 and 224 μM) for 24 hours. The proliferation of FLS was assayed using the CCK-8 reagent. The mRNA expression levels of MMP-1, MMP-3, TIMP-1, COX-2, PEG2, IL-6, and caspase-3, -8 and -9 were evaluated using real-time PCR. In addition, active caspase-3 and MMP-3 were detected by immunocytochemical assay. When treated with levofloxacin for 24 hours, cell viability decreased in a concentration-dependent manner. Furthermore, the protein expression level of active caspase-3 increased, while the protein expression level of MMP-3 revealed no significant changes. In addition, the mRNA levels of MMP-1, MMP-3 and TIMP-1 all increased. Moreover, the mRNA levels of IL-6 and COX-2 decreased, while the mRNA levels of Caspase-3 and -8 increased, both in a concentration-dependent manner. The anti-inflammatory and anti-proliferative effects of levofloxacin on FLS are mediated by inhibiting inflammatory cytokines and inducing apoptosis in rabbits. Thus, quinolones might possess a special effect to treat synovitis and relieve inflammatory joint disease.