J Korean Ophthalmol Soc.  2006 Jun;47(6):977-985.

Expression of Nitric Oxide Synthase Isoforms in a Rat Model of Chronic Glaucoma

• Kim YH
• Park CK

Abstract

PURPOSE: This study investigated the expression of three isoforms of nitric oxide synthase (NOS): neuronal (nNOS), inducible (iNOS), and endothelial (eNOS) in an experimental rat model of chronic glaucoma. The aim was to research the role of nitric oxide (NO) as a neurotoxic molecule in connection with damage to and the degeneration of retinal ganglion cells in glaucoma.
METHODS
Retinal tissues were obtained after inducing chronic elevation of intraocular pressure by cauterization of episcleral vessels. We then performed quantification and localization of NOS isoforms through western blot and immuno-fluorescence staining of the tissues.
RESULTS
The expression of nNOS and iNOS increased significantly but that of eNOS did not. nNOS expressed in the amacrine and displaced amacrine cell of the normal retinal tissue, as well as in retinal ganglion cells in the experimental group. iNOS that expressed in the microglia of the normal retinal tissue was also expressed in the cell thought to be an astrocyte or Muller cell end-feet in the experimental group. Administration of L-NAME (NG-nitro-L-arginine-methyl-esther), a non-specific NOS inhibitor, tended to reduce retinal ganglion cell loss, but this result was without statistical significance.
CONCLUSIONS
These results showed that the cytotoxicity of excessive NO took part in retinal ganglion cell loss in glaucoma, and the expression of nNOS in retinal ganglion cells suggests that it may play an important role in the selective death of the retinal ganglion cell.

Keyword

Chronic glaucoma; NO; NOS; Retinal ganglion cell loss

MeSH Terms

Amacrine Cells
Animals
Astrocytes
Blotting, Western
Cautery
Glaucoma*
Intraocular Pressure
Microglia
Models, Animal*
Neurons
NG-Nitroarginine Methyl Ester
Nitric Oxide Synthase*
Nitric Oxide*
Protein Isoforms
Rats*
Retinal Ganglion Cells
Retinaldehyde
NG-Nitroarginine Methyl Ester
Nitric Oxide
Nitric Oxide Synthase
Protein Isoforms
Retinaldehyde