Survival of Alpha and Intrinsically Photosensitive Retinal Ganglion Cells in NMDA-Induced Neurotoxicity and a Mouse Model of Normal Tension Glaucoma.

PURPOSE

We assess if α retinal ganglion cells (αRGCs) and intrinsically photosensitive retinal ganglion cells (ipRGCs) survive in mouse models of glaucoma.

METHODS

Two microliters of N-methyl-D-aspartate (NMDA; 1 mM) or PBS were injected intraocularly 7 days before sacrifice. Immunohistochemical analyses of the retina were performed using antibodies against RNA-binding protein with multiple splicing (RBPMS), osteopontin, and melanopsin. Immunohistochemical analyses also were performed in adult mice with glutamate/aspartate transporter (GLAST) deletion (GLAST knockout [KO] mice), a mouse model of normal tension glaucoma.

RESULTS

NMDA-induced loss of RBPMS-positive total RGCs was 58.4% ± 0.4% compared to PBS-treated controls, whereas the loss of osteopontin-positive αRGCs was 5.0% ± 0.6% and that of melanopsin-positive ipRGCs was 7.6% ± 1.6%. In GLAST KO mice, the loss of total RGCs was 48.4% ± 0.9% compared to wild-type mice, whereas the loss of αRGCs and ipRGCs was 3.9% ± 0.4% and 9.3% ± 0.5%, respectively. The distribution of survived total RGCs, αRGCs, and ipRGCs was similar regardless of the location of the retina.

CONCLUSIONS

These results suggest that αRGC and ipRGC are highly tolerant to NMDA-induced neurotoxicity and NTG-like neurodegeneration in GLAST KO mice.