Abstract
Purpose: :
X–linked juvenile retinoschisis is a common macular degeneration that affects males early in life. It is chararacterized by a splitting of the retina and a reduction in the b–wave of the ERG. We have recently shown that 14 day old Rs1h knockout (KO) mice injected with recombinant adeno–associated viral vector containing RS1 (AAV–RS1) show a normal pattern of RS1 expression and distribution 5 months after injection. This is associated with an enhanced ERG response, increased rod and cone survival, and significant improvement in retinal cell and synaptic organization. The goal of this study is to examine the time course of RS1 expression and distribution, ERG response and retinal cell organization in Rs1h KO mice injected with AAV–RS1.
Methods: :
AAV– RS1 serotype 5 under the control of a mouse opsin promoter was injected into the subretinal space of the right eye of 14 day old Rs1h KO mice. At various times after injection, ERG recordings were carried out and RS1 expression and distribution and retinal cell structure was examined by confocal scanning microscopy.
Results: :
RS1 expression was observed in a few photoreceptors across the retina 1 week after injection. By week 3, there was a significant increase in RS1 expression and distribution both laterally across the outer retina and longitudinally within the bipolar region of the inner retina that continued to increase with time. An increased in the scotopic ERG b–wave response was observed in the injected eye after 4 weeks.
Conclusions: :
Our studies indicate that, after an initial lag period, progressive increase in RS1 expression in photoreceptors and localization to the outer plexiform layer and inner nuclear layer correlates with the recovery of retinal cell and synaptic structure and an increase in the ERG response.
Keywords: gene transfer/gene therapy • retinal degenerations: cell biology • retina