Distribution of beta-amyloid precursor and B-cell lymphoma protooncogene proteins in the rat retina after optic nerve transection or vascular lesion

The expression of beta-amyloid precursor protein (APP) and B-cell lymphoma protooncogene protein (Bcl-2) in retinal cells in the rat was studied using immunocytochemistry at different times after intraorbital optic nerve transection or vascular lesion. Three hours to one month after transection of the optic nerve, a significant increase in APP and Bcl-2 immunostaining was observed in retinal Müller glia but not in retinal neurons. In contrast, injury to blood vessels that supply the eye without cutting the optic nerve resulted in a complete loss of APP and Bcl-2 immunostaining in Müller cells and an increase in immunoreactivity in distinct populations of retinal neurons. The overall pattern of APP immunostaining in Müller cells and neurons was essentially the same as that of Bcl-2 under identical experimental conditions. These results suggest that the expression of APP and Bcl-2 in retinal cells is dependent on the nature and severity of injury, and that rapid and common mechanisms are involved in regulating the expression of these molecules.