Abstract
Purpose :
To characterize the retinal phenotype of a series of mouse models for X-linked retinoschisis (XLRS). These models include a knock-out (KO) of retinoschisin (Rs1) and two knock-in mutants for two human disease-causing point mutations (C59S, R141C).
Methods :
Outer retinal function was evaluated by dark-adapted (DA-) and light-adapted (LA-) full-field electroretinograms (ERGs). Retinal architecture was assessed by optical coherence tomography (OCT).
Results :
In comparison to wild type control, the DA-ERG b-wave was greatly diminished in Rs1-/Y hemizygous KO males and Rs1-/- homozygous females. The DA-ERG a-wave was also reduced in amplitude. DA-ERG results were similar in the two point mutant models. The LA-ERG was also reduced in each of the Rs1 mutants. ERG abnormalities were relatively stable from 8 to 28 weeks of age, and we are following these mice to still older ages. Each model showed prominent schisis in the outer plexiform layer in OCT. In addition, hyper-reflective morphological changes were observed in the photoreceptor layer, namely between the IS/OS transition and cone outer segments. The retinal phenotype of Rs1+/- heterozygous females was comparable to control littermates, with normal amplitude ERGs and no schisis apparent on OCT imaging.
Conclusions :
The results indicate that the phenotype of Rs1 mutant mice replicates that seen in XLRS patients, and varies with the nature of the genetic mutation. These mice will be of value for examination of experimental treatments for this human condition.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.