PROGRAMMED CELL-DEATH OF RETINAL GANGLION-CELLS DURING EXPERIMENTAL GLAUCOMA

The death of retinal ganglion cells during glaucoma is thought to resu lt from damage to their axons as they exit the eye through the lamina cribrosa. In this study, intraocular pressure in the rat was increased to twice the normal averge by cauterizing two limbal-derived veins. T o investigate whether retinal ganglion cells in the glaucomatous eye f ollow an apoptotic type of death, DNA breaks in nuclei were labeled in situ, using a method that specifically incorporates biotinylated deox ynucleotides by exogenous terminal deoxynucleotidyl transferase to the 3'-OH ends of DNA. The active nature of the death mechanism was demon strated by the reduction in numbers of biotin-labeled nuclei after adm inistration of the protein synthesis inhibitor, cycloheximide. Our res ults suggest that retinal ganglion cells of the adult rat die through apoptosis when the intraocular pressure is markedly increased. This ra ises new possibilities in the treatment of glaucomatous damage to the retina, by the potential interruptibility of a program for neuronal de ath. (C) 1995 Academic Press Limited