Cholestanol induces apoptosis of corneal endothelial and lens epithelial cells

PURPOSE. TO determine whether cholestanol induces cornea endothelial and le ns epithelial cell death in vitro. METHODS. Cornea endothelial and lens epithelial cells were cultured in mini mum essential media with 10% fetal bovine serum containing 10 mu g/ml chole sterol in ethanol, 10 mu g/ml cholestanol in ethanol, or 1% ethanol. These cells, stained using the terminal deoxynucleotidyl transferase (TdT) dUTP n ick-end labeling (TUNEL) method, were analyzed by laser cytometer. The acti vities of ICE and CPP32 proteases in cells were also measured. RESULTS. Both cornea endothelial and lens epithelial cells cultured with 10 mu g/ml cholestanol showed a significant loss of viability. The nuclei of these cells cultured with 10 mu g/ml cholestanol were more frequently stain ed than those exposed to 10 mu g/ml cholesterol or 1% ethanol. Quantitative analysis of apoptotic DNA fragmentation confirmed that the cholestanol ind uced apoptosis of these cells in a time-dependent manner. The activities of interleukin-1 beta-converting enzyme (ICE) and CPP32 proteases for cells c ultured with 10 mu g/ml cholestanol were significantly higher than those ob served in control cells. CONCLUSIONS. In vitro, cholestanol was taken up by corneal endothelial cell s and lens epithelial cells, an event that led to apoptosis of these cells.