Herbimycin A in the treatment of experimental proliferative vitreoretinopathy: toxicity and efficacy study

Background: Proliferative vitreoretinopathy (PVR) is partially caused by pe ptide growth factors, stimulating the cell by binding to a transmembrane ty rosine kinase receptor. We studied the effects of herbimycin A (HA), a tyro sine kinase inhibitor, in PVR. Methods: Toxicity studies: Electroretinography and histological studies wer e performed after intravitreal injection of HA. Efficacy studies: Homologou s rabbit dermal fibroblasts were injected intravitreally, followed by injec tion of HA. The presence of tractional retinal detachment (TRD) and severit y of inflammation were assessed. Results: Toxicity studies: Eyes injected with HA exhibited decrease in B-wa ve amplitude initially, with subsequent recovery. Histologically, damage to photoreceptors was evident after injection of high but not of low doses of HA. Efficacy studies: Inflammatory response and the development of TRD wer e significantly reduced with all doses of HA. Conclusions: HA (20 mu M) was found to be effective and safe in preventing the development of inflammation and TRD.