Effects of Etoposide (VP16) on Vertebrate Retinal Function

Abstract

AbstractEtoposide (VP16), a clinically available anticancer compound known as a potent inhibitor of topoisomerase II, was demonstrated to inhibit irreversibly cytomegalovirus (CMV) replication. This study was performed to evaluate nontoxic concentrations of etoposide for intravitreal injection and vitrectomy infusion in patients with CMV retinitis. We used the isolated perfused vertebrate retina technique, an electrophysiological in vitro technique, for examination of retinal toxicity in higher vertebrates. Bovine and human retina preparations were perfused with an oxygen-preequilibrated standard solution. The electroretinogram (ERG) was recorded as transretinal potential using AgAgCl electrodes. The ERG serves as an indicator of the integrity of the photoreceptors, the first retinal synapse, and higher retinal neurons. After recording of stable ERG amplitudes, the drug was added to the solution for 45 min in the following concentrations: 0.0063, 0.021,0.063,0.21, mMol/L. The preparation was then reperfus...