Retinal changes induced by neonatal cocaine exposure in the rat

Retinal abnormalities have been described in both animals and humans exposed to cocaine during development. The present study was designed to examine the morphological repercussions of neonatal exposure to cocaine on the developing retina of the rat. Male Wistar rats were given 15 mg/kg body weight per day of cocaine hydrochloride subcutaneously on postnatal days (PND) 0-6, 13 and 29 and sacrificed at PND 7, 14 or 30; controls were given saline. The retinas were processed for electron microscopy. Retinal quadrants were embedded flat and vertical semithin and ultrathin sections obtained. PND 7 sections showed discrete intraretinal hemorrhages, PND 14 sections showed massive intraretinal hemorrhages and images of ischemic necrosis in the nerve fiber layer and PND 30 sections showed cavity lesions in the hemorrhagic areas, gliosis and pigmented macrophage-rich epiretinal membranes; photoreceptor rosettes were also found. These results are the first morphological demonstration of retinal hemorrhages and associated epiretinal membranes following neonatal exposure to cocaine in the rat. These changes are probably related to the ischemia/hypoxia induced by cocaine.