Fig. 5

XBD173 protects the light-exposed retina from cell death. a–c Representative panorama sections of the retina were stained with DAPI to further characterize structural changes. Light exposure caused severe degeneration particularly of the ONL. XBD173 administration reduced degeneration, represented by a clearly thicker photoreceptor layer, scale bar 200 μM. d–f Representative photomicrographs of TUNEL-stained retinal sections show the amount of apoptotic cells 4 days after light exposure. Light exposure caused a strong increase of apoptotic cells, especially in the ONL. Only very few TUNEL-positive cells were visible after XBD173 administration. Scale bar 50 μm (g). For quantification of retinal thickness, anterior and posterior areas were divided into ten sections with the optic nerve as reference and rows of photoreceptor nuclei were counted. Data show mean ± SEM (control n = 4, light exposure plus vehicle treatment n = 8, light exposure plus XBD173 treatment n = 10/group) with *p < 0.05; **p < 0.01; ***p < 0.001 light exposed + vehicle versus control (red color) and light exposed + XBD173 versus light exposed + vehicle (blue color). h mRNA analyses revealed a significantly lower expression of caspase 8 in light-exposed XBD173-treated mice compared to controls and vehicle-injected retinas. Data show mean ± SEM out of two independent experiments (control n = 4, light exposure plus vehicle treatment n = 8, light exposure plus XBD173 treatment n = 8/group, measured in triplicates) with **p < 0.01; ***p < 0.001