Abstract
Purpose:
The doublecortin-dsRed transgenic reporter rat was designed to analyze neurogenesis in the aged brain. Doublecortin (DCX) is specifically and transient active in neuronal precursors and young neurons. The aim of this study was to characterize possible DCX-dsRed positive cells in the adult rat retina and to analyze whether the DCX-dsRed rat might represent an appropriate model to study neuronal de- and regeneration in the rat eye in different pathological situations (e.g., ocular hypertension, optic nerve transection, diabetes).
Methods:
Whole mounts and sections of adult DCX-dsRed rat retinas were prepared for immunohistochemistry and tested for the neuronal markers DCX, NF200, Brn3a1, SOX2, calbindin, calretinin, PKCa, ChAT as well as the glial markers GFAP and CRALBP. Co-localization with dsRed positive cells was analyzed via confocal laser-scanning microscopy.
Results:
In adult DCX-dsRed transgenic rats, dsRed-positive cells were detected in the inner nuclear layer (INL), the ganglion cell layer (GCL) and in perivascular cells. DsRed positive cells in the INL showed co-localization with the horizontal cell marker calbindin and were also positive for NF200 and DCX, but were lacking the Müller glia marker CRALBP, the rod bipolar marker PKCa, the amacrine cell marker ChAT, and the progenitor marker SOX2. About half of all dsRed positive cells in the INL were lacking the above mentioned markers and could not be classified yet. In the GCL the majority of dsRed positive cells showed co-localization with the ganglion cell marker Brn3a, while a minority displayed immunoreactivity for calbindin only (probably representing displaced amacrine cells). A subpopulation was enmeshed by GFAP positive filaments and showed perivascular localization.
Conclusions:
In adult rat retina, DCX-dsRed cells in the GCL were identified as retinal ganglion cells, amacrine cells and perivascular cells, while in the INL part of dsRed positive cells represented horizontal cells. Although the DCX-dsRed staining in the retina do not seem to mark retinal neuronal progenitor cells specifically, as seen in the brain, this model represents an useful tool to study retinal ganglion cells in pathological conditions, such as glaucoma.
Keywords: 419 anatomy •
688 retina