Photoreceptor cell death in low light retinal exposure.

BUSSI CLAUDIO; GUIDO MARIO EDUARDO; CONTIN MARIA ANA

Huerta Grande

Congreso; Sociedad Argentina Neuroquímica (SAN) XXV Reunión Anual.; 2010

Sociedad Argentina Neuroquímica (SAN)

PHOTORECEPTORS CELL DEATH IN RETINAL LOW LIGHT DAMAGE Cláudio Bussi, DM Verra 1, ME Guido 1 and  MA Contín 1 1CIQUIBIC (CONICET) ? Dpto Qca Biol, Fac Cs Químicas, UNC-Córdoba; mcontin@mail.fcq.unc.edu.ar Retinitis pigmentosa (RP) or A vitamin deficiencies are characteristic of leading to progressive death of rod and cones photoreceptors with subsequent retinal degeneration.  Typical symptoms are night blindness, decrease in visual field and finally blindness. It is known in some kind of RP and in A vitamin deficiencies the photoreceptor death is due a constitutive activation of the phototransduction mechanism, but the nature of the biochemical events of these apoptosis is unknown to the present. Our objective is to study the molecular mechanism of retinal degeneration in Wistar rat retina kept in dim light (200 lux) during different period of times to maintain the phototransduction mechanism activated. Our results showed a significant reduction of outer nuclear layer (ONL) thickness in rat retina maintained during ten days in dim light. Analysis by Western blot showed the active form of caspase 3 and the possible degradation of rhodopsin and melanopsin during the first five days of exposure. These results indicate that the continuous activation of phototransduction mechanism produce the beginning of  apoptosis cell whiting first five days of light activation whit a caspase 3 dependent mechanism which ONL reduction is visible after ten days of exposure.