Exp Neurobiol.  2018 Feb;27(1):16-27. 10.5607/en.2018.27.1.16.

Functional Analysis and Immunochemical Analyses of Ca²⁺ Homeostasis-Related Proteins Expression of Glaucoma-Induced Retinal Degeneration in Rats

• Lee JY
• Oh SJ

• KMID: 2405305
• DOI: http://doi.org/10.5607/en.2018.27.1.16

Abstract

The retinal degeneration resulting from elevated intraocular pressure was evaluated through functional and morphological analyses, for better understanding of the pathophysiology of glaucoma. Ocular hypertension was induced via unilateral episcleral venous cauterization in rats. Experimental time was set at 1 and 3 days, and 1, 2, 4, and 8 weeks post-operation. Retinal function was analyzed using electroretinography. For morphological analysis, retinal tissues were processed for immunochemistry by using antibodies against the calcium-sensing receptor and calcium-binding proteins. Apoptosis was analyzed using the TUNEL method and electron microscopy. Amplitudes of a- and b-wave in scotopic and photopic responses were found to be reduced in all glaucomatous retinas. Photopic negative response for ganglion cell function significantly reduced from 1-day and more significantly reduced in 2-week glaucoma. Calcium-sensing receptor immunoreactivity in ganglion cells remarkably reduced at 8 weeks; conversely, protein amounts increased significantly. Calcium-binding proteins immunoreactivity in amacrine cells clearly reduced at 8 weeks, despite of uneven changes in protein amounts. Apoptosis appeared in both photoreceptors and ganglion cells in 8-week glaucomatous retina. Apoptotic feature of photoreceptors was typical, whereas that of ganglion cells was necrotic in nature. These findings suggest that elevated intraocular pressure affects the sensitivity of photoreceptors and retinal ganglion cells, and leads to apoptotic death. The calcium-sensing receptor may be a useful detector for alteration of extracellular calcium levels surrounding the ganglion cells.

Keyword

electroretinography; Ca²⁺-sensing receptor; retinal ganglion cell; apoptosis; glaucoma; rats

MeSH Terms

Amacrine Cells
Animals
Antibodies
Apoptosis
Calcium
Calcium-Binding Proteins
Cautery
Electroretinography
Ganglion Cysts
Glaucoma
Immunochemistry
In Situ Nick-End Labeling
Intraocular Pressure
Methods
Microscopy, Electron
Ocular Hypertension
Rats*
Receptors, Calcium-Sensing
Retina
Retinal Degeneration*
Retinal Ganglion Cells
Retinaldehyde*
Antibodies
Calcium
Calcium-Binding Proteins
Receptors, Calcium-Sensing
Retinaldehyde