Figure 3. Changes in platelet-derived growth factor (PDGF) receptor (PDGFR)-β-mediated pathways in senescent vascular smooth muscle cells (VSMCs). Cells were treated with different concentrations of CoCl2 for 72 hr. Expression and activation levels of PDGFR-β were analyzed using an RT-PCR (A) and Western blotting (B), respectively. The phosphorylation levels of the downstream signaling molecules of PDGFR-β were examined after 15 min of stimulation with 25 ng/ml PDGF-BB under serum-free condition (C). * p < 0.05, ** p < 0.01 compared to the group treated with 10% FBS or PDGF-BB alone.