Objective: Kashin-Beck Disease (KBD) is an endemic,age-related degenerative osteoarthritis and its cause is hypothesised to involve Fusarium mycotoxins,commonly associated with inappropriate storage of crops.This study sought to investigate the Fusarium mycotoxin Nivalenol (NIV),widely distributed in the cereals of KBD afflicted areas,on the metabolism of articular chondrocytes in vitro.Methods: The effect of 0.1,0.2 or 0.5μg/ml NIV,on primary bovine articular chondrocyte matrix metabolism was investigated using quantitative PCR to analyse transcript levels of matrix proteins e.g.types Ⅰ and Ⅱ collagen,aggrecan,matrix metalloproteinases (MMPs),aggrecanases (ADAMTS) and the tissue inhibitors of MMPs (TIMPs).Amounts of sGAG,MMPs and TIMPs released by the chondrocytes were assessed using the Dimethylmethylene Blue assay,gelatin zymography and reverse gelatin zymography respectively.Cytoskeletal element organisation was analysed using immunofluorescence in conjunction with scanning laser confocal microscopy,and expression levels measured by quantitative PCR and Western blot analysis.Results: A NIV dose-dependent increase in aggrecan transcription,concomitant with sulphated glycosaminoglycan retention in the cell lysate was observed.Furthermore,NIV significantly increased MMPs 2,-3 and -9,ADAMTS-4 and -5,and TIMPs 2 and -3 transcript expression.In contrast,NIV inhibited type I collagen,MMP 1 and TIMP 1 mRNA levels.NIV promoted extensive cytoskeletal network remodelling,particularly evident for vimentin where there was dose-dependent peri-nuclear aggregation.Conclusion: Our studies have shown that NIV decreased matrix deposition,whilst enhancing catabolic enzyme production,suggesting its potential pro-catabolic ability in chondrocytes.We hypothesise that the observed reduction in matrix production may be attribouted to the extensive remodelling and/or disassembly of the cytoskeletal elements in response to NIV.Collectively,these findings support the hypothesis that trichothecenes mycotoxins,and in particular NIV,has the potential to induce both matrix catabolism and propagate the pathogenesis of KBD.