Figure 4. Increased retinal ganglion cell survival in the RGS2−/− mice. To determine the effect of RGS2 on retinal ganglion cell survival in the RGS2−/− mice, we used retinal cryosections derived from 12 to 15-month old male mice and immunolabeled ganglion cells with Brn-3-specific antibody. The same specimens were also stained with Hoechst 33258 dye to count the total number of cells in the ganglion cell region. Panels A and B show Brn-3-specific immunostaining (red), C and D show Hoechst staining (blue), and E and F depict the overlapping of Brn-3 and Hoechst staining. G: Quantitative changes in the Brn-3-positive retinal ganglion cells between the RGS2−/− and wild-type mice. H: Quantitative changes in the total number of cells in the ganglion cell region of the retina in RGS2−/− and wild-type mice. The RGS2−/− mice show a significant increase in Brn-3-positive cells in the ganglion cell region of the central retina as compared to the wild-type mice. The total number of cells in the ganglion cell region of the central retina based on Hoechst staining did not show significant difference between two groups of the mice. Cell number is expressed per unit area, and values are expressed as mean±SEM (n=4). The asterisk indicates a p<0.05. Abbreviations: ganglion cell layer (GCL); inner plexiform layer (IPL); inner nuclear layer 563 (INL); outer nuclear layer (ONL); outer plexiform layer (OPL). Scale bar represents 100 μm.