Abstract
Purpose:
The purpose of this study was to examine the changes of the expression of synapses at the retina in a chronic ocular hypertension rat model.
Methods:
Chronic ocular hypertension was induced by three episcleral vein cauterization. Expression of synaptophysin was co-localized with ganglion cell marker (NeuN), rod bipolar cell marker (PKCα), and A2-amacrine cell marker (parvalbumin). Electron microscopic examination was done at 1 week, 2 weeks, 4 weeks, and 8 weeks after cauterization.
Results:
Expression of synaptophysin was increased throughout the layers of the retina, especially in the inner and outer plexiform layers. Co-localization with NeuN, PCKα, and parvalbumin shows that there are increase in synapses between ganglion cells and rod bipolar cells and between rod bipolar cells and photoreceptors. Immunohistochemical staining shows dendrites of the retinal ganglion cell increases. Electron microscopy shows increase of the dendrites of retinal ganglion cell and increase in the number of ribbon synapses in the inner and outer plexiform layers.
Conclusions:
This data suggest that there is increase in synapses between retinal cells after ocular hypertension. The role of this phenomenon needs further investigation.
Keywords: 531 ganglion cells •
435 bipolar cells