Figure 3.

Resveratrol suppressed AGEs-stimulated AP-1 signaling. Similar to Figure 2A, Chondrocytes pretreated with various doses of resveratrol were stimulated with 100 μg/ml AGEs and the cells were collected and the nuclear extracts were prepared for determining DNA-binding activity of AP-1 and SP-1 by EMSA (a). The total cell lysates from chondrocytes treated with 100 μg/ml AGEs for 4 h in the presence or absence of pretreatment with various doses of resveratrol were prepared to measure the levels of both un-phosphorylated and phosphorylated ERKs by Western blot (b). In (c), cells were treated in the presence or absence of resveratrol and the total cell lysates were prepared and then immune-precipitated with anti-JNK antibodies. The kinase assays were performed with GST-c-Jun as the substrate. The protein levels of total JNK and β-actin determined by Western blot were presented as controls. In (d), the effects of resveratrol on AGEs-induced AP-1 transcriptional activity were determined. The results were shown as fold inductions of luciferase activity as compared to the unstimulated sample. Values are means ± standard deviations (error bars) for three independent experiments. *: P < 0.05 compared to the AGE-stimulated in the absence of resveratrol treatment.