Figure 2.

Inhibitory effects of cynaroside on IL-1β-induced nitrite, ROS, PGE₂, TNF-α, iNOS, and Cox-2 in primary rat chondrocytes. Cells were pretreated with cynaroside (40, 80, and 160 μM) for 1 h, followed by IL-1β (10 ng/mL) stimulation for 24 h. (a) Nitrite production was determined in the cultured medium using a Griess reagent. (b) ROS levels were detected by H₂DCF-DA probe. (c, d) PGE₂ and TNF-α production was determined in the cultured medium by ELISA. (e) Expression of the iNOS, Cox-2, and TNF-α was determined using western blot analysis. (f) Quantitative data of (e) were analyzed using ImageJ software. α-Tubulin served as an internal control. Expression 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; ROS: reactive oxygen species; PGE₂: prostaglandin E₂; TNF-α: tumor necrosis factor-alpha; iNOS: inducible nitrite oxide; Cox-2: cyclooxygenase-2.