Chondroprotective Effect of Cynaroside in IL-1β-Induced Primary Rat Chondrocytes and Organ Explants via NF-κB and MAPK Signaling Inhibition

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 of three independent experiments. ^## compared with the control group; , , and 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.

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