Abstract
Purpose: :
To determine the extent of dendritic and axonal atrophy of retinal ganglion cells in diabetic mice.
Methods: :
Heterozygous male Ins2Akita mice (stock #003548) were crossed with female mice that express a transgenic construct for yellow fluorescent protein (YFP) under the Thy–1 gene promoter (stock #003782, Jackson Laboratory). The male progeny were used in the analysis. At 4 months of age, the retinas were fixed in paraformaldehyde and isloated. The YFP labeling was enhanced with rabbit anti–GFP conjugated to Alexa 488 (Molecular Probes) and analyzed using confocal microscopy.
Results: :
In both diabetic and non–diabetic control littermates, 20 to 40 retinal ganglion cells expressed the YFP gene, rendering the entire dendritic structure fluorescent under 488 nm laser excitation. Each ganglion cell was classified by measuring the dendritic field area, depth of the dendrites in the inner plexiform layer and total dendritic length. In retinas from diabetic mice, several subtypes of ganglion cells had a prominent thinning of their axons soon after the axon hillock, whereas others had uncharacteristic swelling of their primary dendrites.
Conclusions: :
This model is an ideal method to study the pathological changes of retinal ganglion cells in the Ins2Akita diabetic mouse. The morphology of a subpopulation of ganglion cells were altered by diabetes. The structural atrophy of retinal ganglion cells may contribute to the loss of vision function in diabetes.
Keywords: diabetic retinopathy • retinal degenerations: cell biology • ganglion cells