Examining diabetic retinopathy in the zebrafish (Danio rerio) model

According to NIDDKD, 12,000--24,000 new cases of blindness due to diabetic retinopathy are reported yearly in the United States (Diseases 2005). This disease has well established models in mice and rats, but they have little genetic tractability, small sample sizes, and are expensive (Goldsmith, 2001). As an alternative researchers have begun looking at zebrafish, Danio rerio, as a model of diabetic retinopathy. Our work provides further information on the pathology of diabetic retinopathy in zebrafish by looking at GFAP and VEGF expression and pericyte cell changes following prolonged exposure to hyperglycemia. We found that GFAP expression has some fluctuations within the first month and noted expression is limited to Muller cell processes and endfeet. We were unable to detect VEGF expression, but provide suggestions to enhance detection. Lastly, we applied a trypsin digest protocol to eye tissue, to visualize vascular pericyte and endothelial cells. In some samples, we had difficulties identifying pericyte cells, but propose markers that will ease identification for future studies.