Immunocytochemical localization of gentamicin in the rabbit retina following intravitreal injection.

The localization of gentamicin in the retina after a single intravitreal injection in the rabbit eye was examined by indirect immunofluorescent staining with goat antigentamicin antiserum. Eight hours after the injection of 400 micrograms of gentamicin, staining was observed in the ganglion cell layer, the inner plexiform layer, the inner nuclear layer, and the photoreceptors. By 12 hours, the staining was also observed in the retinal pigment epithelium. Howeever, by 24 hours the staining was predominantly found in the retinal pigment epithelium and choriocapillaris, and only occasional staining was seen scattered in the neurosensory retina. At 36 to 48 hours, the labeling was confined to the retinal pigment epithelium and choriocapillaris. Electron microscopy confirmed the cytoplasmic localization of gentamicin in the retina.