NO, PGE2, MMP-13, collagen II and aggrecan quantification
Nitrate/Nitrite colorimetric assay and prostaglandin E2 Enzyme Immunoassay (EIA) kits were obtained from Cayman Chemical (Ann Arbor-MI, USA). Human ELISA Kits for MMP-13, Collagen II and Aggrecan detection were purchased from Abcam® (Paris, France). The NO, PGE2, MMP-13 and Aggrecan level measurements were performed according to manufacturer’s instructions in cell supernatants whereas collagen II amount was measured in cell lysate. For human serum, measurements were performed in quadruplicates for each sample of the ten volunteers.