BACKGROUND In order to develop new strategies for the pharmacological modulation of posttraumatic and postsurgical wound healing of the corneal stroma, the effect of Trapidil, a competitive platelet-derived growth factor (PDGF) antagonist, on the proliferation of cultured bovine stromal fibroblasts (BSF) was investigated. METHODS BSF, obtained from explant cultures, were seeded at a cell density of 100/mm2. The effect of various concentrations of Trapidil on cell viability and cell proliferation was determined using three different culture conditions: (1) serum-free medium (WM/F12), (2) serum-containing medium (WM/F12 + 10% FCS), and (3) serum-free medium + 50 ng/ml PDGF-BB. Trapidil was added in concentrations ranging from 100 micrograms/ml to 400 micrograms/ml. Cell numbers were determined 2 and 5 days after addition of Trapidil, using a computer-based cell-counting system. Cell viability was evaluated morphologically and by means of a repopulation assay. RESULTS Addition of Trapidil (100-400 micrograms/ml) led to a significant, dose-dependent inhibition of both serum- and PDGF-BB-induced proliferation of BSF. In contrast, treatment of quiescent BSF, cultured in serum-free medium, did not result in a significant reduction of cell number. No cytotoxic effects were observed. CONCLUSIONS The results of the present study demonstrate an inhibitory effect of Trapidil on the proliferation of BSF. It can be assumed that application of Trapidil might be a useful tool in the prevention of corneal complications after trauma (e.g., scarring, astigmatism and--with respect to photorefractive procedures--formation of haze and regression of the refractive effect).