Platelet-derived growth factor receptor kinase inhibitor AG1295 and inhibition of experimental proliferative vitreoretinopathy

Purpose: Receptor tyrosine kinase (RTK) activation is critical for growth factor-mediated cell proliferation. The present study was designed to determine the effect of tyrphostin AG1295, a selective blocker of platelet-derived growth factor (PDGF) RTK, on proliferative vitreoretinopathy (PVR) development. Methods: Rabbit conjunctival fibroblasts cells (1x10(4)) were seeded into 96-well plates and maintained in Dulbecco's modified essential medium (DMEM) with 0.5% fetal bovine serum. The cells were exposed to 50 ng/mL PDGF-AA or PDGF-BB or phosphate-buffered saline with or without AG1295 (1 muM, 10 muM, and 100 muM). After 3 days, the viable cells in each well were measured by 3,(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Homologous rabbit conjunctival fibroblasts were injected intravitreally, followed by injection of 100 muM of AG1295. The development of tractional retinal detachment (TRD) was assessed to evaluate the effect of AG1295 in vivo. Electroretinography and histologic studies were performed after intravitreal injection of AG1295 into untreated eyes to evaluate toxicity. Results: Two concentrations of AG1295 (10 and 100 muM) significantly inhibited rabbit conjunctival fibroblast cell growth stimulated by PDGF-AA or PDGF-BB in vitro. Development of TRD was significantly attenuated (P<.01) with 100 μM of AG1295 until day 21. No significant histologic or retinal functional damage was found in the AG1295-treated group. Conclusions: PDGF receptor specific inhibitor AG1295 attenuated PVR without significant side effects in rabbits. This reagent could be a useful treatment to prevent PVR.