ZeEfficacy – Efficacy Services

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Retinal Degeneration Model

Dry Age-related Macular Disease (Dry-AMD) is a common eye disorder leading to gradual reduction of vision, characterized by progressive loss of the photoreceptor cell population in the retina

Given the high anatomic and functional conservation between human and zebrafish retina, adult zebrafish are very suitable to model human eye disorders.

We offer a comprehensive and biologically translatable method to study human retinal degeneration pathogenesis and evaluate the efficacy of Dry-AMD therapies.

Applications

  • Study retinal degeneration and regeneration processes.
  • Study the molecular and physiological mechanisms of Dry-AMD.
  • High throughput screening of compounds with potential capacity to protect from degeneration or enhance regeneration of photoreceptors in the retina.

Advantages

Zebrafish and human retina are highly conserved both anatomically and functionally.

Fast development of the eye.

Transparency of the model.

Method description

The assay is divided into different phases. For testing compound’s capacity to protect from degeneration the order of phases is the following:

  1. Adaptation of adult fish in complete darkness
  2. Intravitreal injection of the compound of interest
  3. Constant light exposure (60 hours) for inducing retinal damage (Light-Induced Degeneration, LID)

For testing pro-regenerative compounds, the injection of the molecule is performed after retinal damage is achieved.

Treated and control eyes are enucleated and fixed. Cryosections of the eyes are immuno-stained against a photoreceptor marker to evaluate this cell population. Imaging is done by confocal microscopy; and analysis is performed through a custom image analysis software that allows process automation and unbiased analysis between samples.

Figure 1. Retinal cryosections of adult zebrafish eyes immunostained for a photoreceptor marker (red) and nucleus marker (blue). A) Negative control: fish not exposed to constant light (without retinal damage); B) Fish exposed to 60 h LID; C) Fish exposed to 60 h LID upon injection with vehicle; D) Fish exposed to 60 h LID upon injection with an active compound that protect from regeneration. The Outer Nuclear Layer (ONL) is marked with a white bar.

Readouts

  • The thickness and cell number of the Outer Nuclear Layer (ONL), the retinal layer populated by rod and cone photoreceptors.
Figure 2. ONL cell thickness and cell number evaluation on four different conditions. Negative control (fish not exposed to constant light, without retinal damage); Fish exposed to 60 h LID; Fish exposed to 60 h LID upon injection with vehicle; Fish exposed to 60 h LID upon injection with an active compound that protect from regeneration.