Figure 3.

Percentage of retinal ganglion cells (RGC) lost at 6 months in rat eyes with chronic, moderately elevated IOP. One week after Fluoro-Gold labeling, retinal ganglion cells were counted in both eyes of each animal (n = 6 for the aminoguanidine-treated group; n = 6 for the untreated group). RGCs were counted in the peripheral retina (A), approximately 4.0 mm from the optic disk, and in the central retina (B), approximately 1.0 mm from the optic disk. To demonstrate uniform bilateral distribution of Fluoro-Gold in retinal ganglion cells after bilateral injection into the superior colliculus, a separate group of normal animals (n = 6) was studied. These animals had normal IOP bilaterally. The mean ± SD of the ratios of retinal ganglion cell counts for left and right eyes were 0.99 ± 0.16 in the peripheral retina and 1.02 ± 0.05 in the central retina. These values were used for the determination of percent RGC lost at “0 Month” (CONT); % RGC lost = 1 − [RGC density in eye with elevated IOP/RGC density in eye with normal IOP] × 100%. In peripheral retina at 6 months, percent RGC lost in eyes with elevated IOP from animals that were not treated pharmacologically (NT) is statistically significantly different than control (P < 0.01), whereas percent RGC lost in eyes with elevated IOP from animals that were treated with aminoguanidine (AG) is not statistically significantly different than control (P > 0.1). All values are mean ± SD.