MECANISMO DE MUERTE DE CÉLULAS FOTORRECEPTORAS POR EXPOSICIÓN A LA LUZ A BAJA INTENSIDAD

CONTIN MARIA ANA; ARIETTI, MILAGROS; GUIDO MARIO EDUARDO

Huerta Grande

Congreso; Sociedad Argentina de Neuroquimica; 2011

Sociedad Argentina de Neuroquimica

Retinal degeneration by defect in phototransduction mechanism is characterized by apoptosis of photoreceptors cells. Constant low light exposure produces photoreceptor cell death through the activation of downstream signal transduction. The present study examined the time course and molecular apoptotic mechanism occurring during retinal degeneration after continuous low light intensity exposure. Wistar rats were exposed to constant illumination with cool white fluorescent light (LL) of 200 lux for 1 to 10 days and compared with controls kept in the dark (DD) or exposed to a regular 12:12 h (LD) cycle. Histological analysis showed a significant reduction of the outer nuclear layer (ONL) after 4 days of LL as compared with LD or DD controls. Retinal analysis by flow cytometry showed an increase of apoptosis in light-exposed rats. Moreover there was a progressive collapse of the outer segments (OS) and inner localization of rhodopsin immunoreactivity in the photoreceptor somas during LL exposure. The study of activated caspase-3 demonstrated a caspase-3 independent mechanism by both Western blot and enzyme activity assays.