Abstract
Purpose: :
Glial Fibrillary acidic protein (GFAP) is a well known indicator of retinal stress and its level has been found to be up–regulated in Müller cells in age related macular degeneration. The aim of the present study was to determine whether GFAP expression was increased in Müller cells in the Monocyte Chemoattractant Protein (MCP–1) mutant mice, an animal model of AMD.
Methods: :
MCP–1 mutant mice were obtained from an existing colony at Feinberg School of Medicine at Northwestern University. For immunocytochemistry, animals were enucleated and the eyes were fixed in 4% paraformaldehdye. Cryostat sections of the eye (20µm) were treated with a polyclonal antibody against GFAP and the antibody binding was visualized using a TRITC–conjugated secondary antibody
Results: :
In retinas from six month old animals, there was strong labeling of astrocytes but the Müller cells appeared to be negative. In the far peripheral retina, however, there was evidence of retinal thinning and Müller cells expressed GFAP. The retinas from a seventeen month old–animal showed GFAP in Müller cells throughout the retina. Moreover, the GFAP staining was not limited to a radial distribution but was found in small patches in the retina. This was most likely due to severe disorganization of the inner retina
Conclusions: :
The present study shows that there is an increase in GFAP expression in retinal Müller cells as the MCP–1 mutant mice grow older. GFAP expression in Müller cells might be a useful marker for following the time course of retinal changes in this animal model of AMD.
Keywords: age-related macular degeneration • Muller cells