Muerte de células fotorreceptoras por exposición a la luz a baja intensidad..

BUSSI CLAUDIO; GUIDO MARIO EDUARDO; CONTIN MARIA ANA

Córdoba

Congreso; VII congreso nacional de investigación en visión y oftalmología (AIVO).; 2010

VII congreso nacional de investigación en visión y oftalmología (AIVO).

MUERTE DE CÉLULAS FOTORRECEPTORAS POR EXPOSICIÓN A LA LUZ A BAJA INTENSIDAD PHOTORECEPTOR CELL DEATH IN LOW LIGHT RETINAL EXPOSURE Claudio Bussi, E. Guido  and  Maria A Contín CIQUIBIC (CONICET) ? Dpto Qca Biol, Fac Cs Químicas, UNC-Córdoba; mcontin@mail.fcq.unc.edu.ar Retinal degenerations, including Retinitis Pigmentosa (RP) and vitamin A deficiencies, exhibit progressive death of rod and cone photoreceptors with subsequent loss of vision.  Typical symptoms are night blindness, decreases in visual field and eventually blindness. In some types of RP as well as vitamin A deficiencies, photoreceptor death is due to constitutive activation of the phototransduction pathway, but the biochemical events underlying apoptosis are presently unknown. To answer this question, we are studying the molecular mechanisms involved in retinal degeneration in Wistar rats kept in moderate light (200 lux) to activate phototransduction for different periods of time. Our results showed a significant reduction in outer nuclear layer (ONL) thickness in rat retinas after ten days of continuous light exposure. Western blots detected the active form of caspase 3, and in preliminary results we observed degradation of rhodopsin and melanopsin, during the first five days of exposure. These results indicate that continuous activation of the phototransduction cascade initiates photoreceptor apoptosis within five days of light exposure, and involves a caspase 3-dependent mechanism which leads to measurable cell loss after ten days.