Trapidil Effects on Intimal Thickening and mRNA Levels for Platelet-derived Growth Factor A in Human Saphenous Vein Smooth Muscle Cells

Background: Platelet-derived growth factor (PDGF) A chain, basic fibroblast growth factor (bFGF), and tissue-type plasminogen activator (tPA) from smooth muscle cells (SMCs) have been postulated to initiate SMC proliferation and migration in the process of intimal thickening. Objective: In this study we tested whether trapidil, which is reported to reduce intimal thickening, would suppress mRNA increases for all or only some of these genes in human SMC. Methods: Cultured human saphenous vein SMCs made quiescent by 72-hour incubation in 0.5% serum were stimulated with 3U/mL α-thrombin ± trapidil. Changes in mRNA transcript levels were analyzed by Northern blot. Results: Trapidil decreased thrombin-induced mRNA levels for bFGF and appeared to decrease mRNA for PDGF-A chain, but not for tPA. Conclusion: These results suggest that trapidil may reduce intimal thickening at least partly via the suppression of increased bFGF and PDGF-A chain mRNA levels in vascular SMCs.