Fig. 4

PARP inhibition improves cone photoreceptor survival in rd2 organotypic retinal cultures. The TUNEL-positive cells (green) in rd2 retinal organotypic cultures treated with and without PARP inhibitors (B, F, J, N), DAPI (blue) was used as a nuclear counterstain (A, E, I, M); CAR staining for cones (red) (C, G, K, O) and merged images (D, H, L, P). Circles indicate colocalized cones stained with TUNEL, CAR, and in the merged image. CAR staining indicated a significantly increased percentage and density of cone photoreceptors in the ONL for 100 nM Olaparib and 3 nM BMN-673 treated groups (Q, R). Both the percentage and density of TUNEL-CAR colocalization indicated a significant reduction of photoreceptor death in all treatment groups (S, T). The TUNEL-positive cells significantly reduced in rd2 retinal organotypic cultures treated with PARP inhibitors (U). Comparison of rod, cone and total photoreceptor cell death in rd2 retinal organotypic cultures treated with PARP inhibitors (V). The percentage of cone cell death in total cones in rd2 retinal organotypic cultures treated with PARP inhibitors (W). Arrows indicate representative cone photoreceptors, and circles indicate representative dead cone photoreceptors. The images shown are representative for observations on at least three different specimens for each genotype/treatment condition. n ≥ 5, significance levels: ns > 0.05, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001, ANOVA test, and Dunnett’s test for multiple comparisons