Abstract
Purpose: :
To evaluate whether RNA interference for ASK-1, a gene involved in the mitochondria and endoplasmic reticulum-mediated apoptosis, inhibits the photoreceptor death in retinal degeneration (rd) mice.
Methods: :
Rd mice were euthanized and the retinas were subjected to organ culture at 9 post-natal day. Small interfering RNAs (siRNA) for ASK-1 were transfected into the cultured retina at the onset of experiments. Retinas were fixed at 4 and 7 days of experiment and consecutive cryosections were made, then histological and immunohistochemical examinations were performed.
Results: :
In preliminary experiment, the incorporation of fluorescent siRNA was found in almost cells in the outer nuclear layer and few cells in the inner nuclear layer at the next day of transfection. The thickness of outer nuclear layers of control retinas were decreased with time while that of siRNA transfected retina were significantly preserved (150% of control at day 7, p=0.027). In TUNEL assay, siRNA for ASK-1 significantly decreased the TUNEL positive cells (49% and 42% of control at day 4 and 7, p=0.039 and 0.0028, respectively). The number of ASK-1 immunopositive cells was remarkably reduced in the retina treated with siRNA for ASK-1 compared to control.
Conclusions: :
The RNA interference for ASK-1 may be useful to inhibit the photoreceptor apoptosis in rd mice.
Keywords: retinal degenerations: cell biology • apoptosis/cell death • retinal culture