Neuroprotective Effect of Small Interfering RNA Targeting Against Caspase on Rat Retinal Ganglion Cells Damage Induced by N-methyl-D-aspartate

Abstract

Purpose:: Apoptotic cell death is induced in retinal ganglion cells after intravitreous injection of N-methyl-D-aspartate(NMDA). Caspases play an important role in apoptosis. The purpose of this study was to determine whether small interfering RNA (siRNA) targeting against caspases could protect retinal ganglion cells from apoptosis in rat retina.

Methods:: Seven week- old male Wister rats were used. Prior to the present experiments, we had confirmed the transfection of siRNA into retinal ganglion cells using Alexa fluor 546 labeled siRNA injection into the vitreous. SiRNA specific for rat caspase 3 or caspase 8 were injected into the vitreous 24 hours prior to injection of 20 nmol NMDA (study group). Non- silencing negative control siRNA were injected prior to injection of NMDA (control group). Retinal ganglion cells were labeled with Fluoro-Gold retrogradely and flatmounts of fixed retina were examined by fluorescence microcopy. The number or retinal ganglion cells were compared each groups. The levels of caspase 3 mRNA were analyzed by real-time RT-PCR and were also compared each groups.

Results:: Compared with control group, retinal ganglion cell loss and the expression of caspase3 RNA were suppressed in siRNA targeting caspase 3 injected eyes group. There ware no significant difference between siRNA targeting caspase 8 injected eyes and control group in number of retinal ganglion cells.

Conclusions:: The siRNA targeting caspase3 may protect the retinal ganglion cells damage induced by NMDA.

Keywords: neuroprotection • apoptosis/cell death • ganglion cells