토끼 망막에서 NMDA에 의한 아포프토시스의 발현

N-Methyl-D-Aspartate (NMDA)-induced Apoptosis in Rabbit Retina

Purpose: To evaluate the involvement of apoptosis in N-methyl-D-aspartate (NMDA)-induced excitotoxicity in the rabbit retina. Methods: After intravitreal injection of 680 and 2,000 nmoles of NMDA in rabbit eyes, the eyes were enucleated at 2, 16, and 60 hours and 1 and 2 weeks. The apoptotic cell death was determined with TdT-mediated biotin-dUTP nick end labeling (TUNEL) stain, and immunohistochemical stains of Bcl-2, Bax, and caspase-3 were performed. Results: TUNEL showed increased labeling scattered in the ganglion cell layer and inner nuclear layer from 16 to 60 hours. The number of TUNEL-positive nuclei decreased at 60 hours, and none was observed at 2 hours, 1 week, and 2 weeks. More TUNEL-positive nuclei were seen with injection of 2,000 nmoles compared to 680 nmoles. Bcl-2, Bax, and caspase-3 were seen histologically as early as 2 hours in the ganglion cell layer and inner nuclear layer; there was no stained nuclei with the TUNEL stain. At 2 hours after intravitreal NMDA injection, Bcl-2, Bax, and caspase-3 were also stained in Müller cells. Conclusions: This study showed that apoptosis is involved in NMDA-induced excitotoxicity in the rabbit retina. Bcl-2, Bax, and caspase-3 may play important roles in modulating the apoptosis in NMDA-induced excitotoxicity, and Müller cells are involved in the apoptotic pathway. J Korean Ophthalmol Soc 49(7):1146-1153, 2008