Figure 6.

Chondroprotective effects of cynaroside in rat explant organs (legs). Explanted legs were pretreated with cynaroside (40, 80, and 160 μM) for 1 h, followed by IL-1β (10 ng/mL) stimulation for 4 days. (a) Nitrite production was determined in the cultured medium using a Griess reagent. (b) PGE₂ production was determined in the cultured medium using ELISA. (c) Protein levels of iNOS, Cox-2, MMP-13, and ADAMTS-4 were determined using western blot analysis. (d) Quantitative data of (c) were analyzed using ImageJ software. α-Tubulin served as an internal control. (e) Histological analysis of proteoglycan loss was carried out by Safranin O staining and the Osteoarthritis Research Society International (OARSI) advanced Osteoarthritis Cartilage Histopathology Assessment System. Results are represented as mean ± SD of three independent experiments. ^##p < 0.01 compared with the control group; ^∗p < 0.05, ^∗∗p < 0.01, and ^∗∗∗p < 0.001 compared with the IL-1β-treated group. CON: control; RNS: reactive nitrogen species: PGE₂: prostaglandin E₂; iNOS: inducible nitrite oxide; Cox-2: cyclooxygenase-2; MMP: matrix metalloproteinase; ADAMTS-4; a disintegrin and metalloproteinase with thrombospondin motifs 4.