[Expression of glutamate receptor 2 in retinal ganglion cells in the eyes with chronic elevated intraocular pressure: experiment with rats].
OBJECTIVE
To investigate the mechanism of selective damage of retinal ganglion cells (RGCs) in glaucoma.


METHODS
(1) The right eyes of 12 SD rats underwent ligation of 2 episcleral veins and subconjunctival injection 5-fluoro-uracilum so as to establish chronic elevated intraocular pressure glaucoma rat model. Six SD rats were used as controls. Intraocular pressure (IOP) was measured every week. (2) One week and 4 weeks after the operation 6 glaucoma rats and 3 control rats were killed with their eyes taken out to undergo immuno-histological assays to observe the expression of glutamate receptor (GluR)-2 and neurofilament (NF)-68 in the RGCs with different sizes by confocal laser scanning microscope.


RESULTS
(1) The IOP was increased since 1 week after the operation. The elevated IOP was consistently maintained for up to 4 weeks in the glaucoma group. (2) All the RGCs of both groups were NF-68 positive, especially the larger RGCs. (3) GluR2 was not expressed in the larger RGCs of both the glaucoma and control groups, and was expressed in the small and intermediate RGCs of the glaucoma group up to the end of experiment. However, 4 weeks after the operation the residual NF-68 positive larger RGCs of the glaucoma group showed GluR-2 expression.


CONCLUSIONS
The vulnerability of the RGCs may be related to the specific deficiency of GluR-2 expression.
Ling
Zhi-hong
ZH
Department of Ophthalmology, EENT Hospital, Fudan University, Shanghai 200031, China.
Sun
Xing-huai
XH
D000818:Animals; D002908:Chronic Disease; D004195:Disease Models, Animal; D007150:Immunohistochemistry; D008297:Male; D018613:Microscopy, Confocal; D016900:Neurofilament Proteins / Q000096:biosynthesis*; D009798:Ocular Hypertension / Q000473:pathology / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000096:biosynthesis*; D012165:Retinal Ganglion Cells / Q000378:metabolism*
D016900:Neurofilament Proteins; D018091:Receptors, AMPA; C066858:neurofilament protein NF 68; C104722:glutamate receptor ionotropic, AMPA 2