Background Sulforaphane [SFN; 1-isothiocyanato-4-(methylsulphinyl)-butane], a naturally occurring isothiocyanates (ITC) obtained through the consumption of broccoli, is one of the most potent inducers of the phase 2 enzymes implicated in carcinogen detoxification . In addition to its chemopreventive activity, SFN inducers have been recently found to have anti-inflammatory activity . Recent study suggests that SFN suppresses matrix metalloproteinase (MMP) production from articular chondrocytes stimulated with either IL-1 or TNF-a and that SFN inhibits NF-KB and JNK activation in pro-inflammatory cytokine-stimulated articular chondrocytes .
Objectives In this study, chondrocytes derived from OA pateints were used for in vitro model to investigate the protective effect of SFN on inflammatory damage induced by lipopolysaccharide (LPS). In addition, we devised SFN delivery system using biodegradable poly(lactide-co-glycolide) (PLGA) and demonstrated that the system has enduring chondroprotective effect on inflammatory damage induced by LPS.
Methods Articular cartilages were obtained from knee OA patients and were cultured in monolayers. The cells were pretreated with 1 mg/ml LPS for 6 h and subsequently with 0–20 mM SFN for 18 h. Effect of PLGA-based SFN delivery system on cartilage protection was examined by the experiments using transwell insert. The cell cytotoxicity was determined by MTT assay and the expression of COX-2, ADMATS-5, MMP-2 and TIMP-2 was evaluated by western blotting and RT-PCR.
Results SFN was not toxic to chondrocytes upto the dose of 5 mM. However, SFN at 5 mM significantly inhibited mRNA expression and protein level of ADAMTS-5 and MMP-2 without cytotoxicity in chondrocytes. In addition, slow release SFN delivery system (SFN-PLGA) inhibited mRNA and protein level of COX-2, ADAMTS-5 and MMP-2 by LPS in chondrocytes. TIMP(tisuue inhibitor of MMPs)-2 mRNA expression and protein level were increased by SFN-PLGA system.
Conclusions These results indicated that SFN has chondroprotective effect on inflammatory damage induced by LPS. PLGA-based delivery system may provide a effective tool for the controlled release of SFN.
Acknowledgements: This work was supported by a grant from the Korea National Research Foundation of Korea (Grant No 2011-0027473).
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Disclosure of Interest None Declared