Abstract
Purpose: :
To study astroglial changes in the retina of apoE knock-out (apoE-/-) adult mice, and their relation with the vascular endothelial growth factor (VEGF) availability.
Methods: :
apoE-/- C57BL/6 mice (n=12) and wild-type counterparts (WT) (n=12) 12 months old were used. Retinal whole mounts were immunostained with antibodies against GFAP. The VEGF levels were determined by enzyme-linked immunosorbent assay (ELISA) in the retinal homogenates.
Results: :
In comparison with naïve, astrocytes in apoE-/- mice showed several changes: i) they were significantly reduced in number when the analysis was made both by the whole retina (p<0.001) and by zones of the retina (p<0.003 for the peripapillary zone and p<0.000 for the intermediate and peripheral zone; ii) their GFAP immunoreactivity (IR) decreased; iii) they had fewer processes and most cell bodies and processes were thinner; iv) the astroglial plexus was unrecognizable in most areas of the retina. GFAP-IR of Müller cells in apoE-/- eyes was increased in comparison with naïve. VEGF expression was significantly lower (p<0,001) in the apoE-/- retina than in the WT.
Conclusions: :
Seeking to provide precise molecular facts that would help in managing retino-vascular damage and visual impairment, we found that apoE seems to be essential for retinal astrocyte survival and homeostasis and as a consequence for neuroprotecion.
Keywords: retinal glia • astrocyte • immunohistochemistry