Effects of uv-visible irradiation of rabbit cornea in the presence of chlorpromazine

Abstract

The phototoxic effects of ultraviolet (UV)-visible irriadiation in the presence of chlorpromazine (CPZ) on the endothelial cells of rabbit cornea in vitro were investigated. For comparison, three types of controls were employed: (1) cornea not irradiated but incubated in the dark in the absence of CPZ (control A), (2) cornea not irradiated but incubated in the dark in the presence of CPZ (control B), (3) cornea irradiated in the absence of CPZ (control C). For identifying the cytotoxic damage we used two criteria: (1) 51Cr release from labeled corneal endothelial cells and (2) changes in cellular morphology as seen with specular, light, and scanning electron microscopy. Our results demonstrated that the corneal endothelial cells were damaged when they were irradiated in the presence of CPZ (5 μg/ml); cellular damage was not observed in the control corneas. It may therefore be concluded that this effect is due to a definite phototoxic mechanism. The cellular damage in the experimental cornea was manifested both morphologically and by the leakage of 51Cr from the labeled corneas. Our experiments showed that it is possible to label the endothelial cells of intact corneas with 31Cr and that this labeling technique can be used successfully to quantify the damage of corneal endothelium under different experimental conditions in vitro. These results also show that corneal organ culture containing the endothelial monolayer of cells is a suitable model for studying cytotoxic effects of various agents, including light and drugs.