Extended Data Fig. 5: P3HT nanoparticles do not promote proinflammatory effects in dystrophic retinas.

Transversal sections of representative retinas dissected at 30 DPI (a–c) and 240 DPI (d–f) from healthy controls (RCS-rdy) and dystrophic RCS rats that were untreated (RCS) or injected with either P3HT-NPs (RCS + P3HT) or control Glass-NPs (RCS + Glass). Sections were immunolabelled for: the astrocyte/Müller cell marker GFAP (a,d), the microglial marker Iba-1 (b,e) and the retinal trophic factor FGF2 (c,f). Images were acquired from corresponding fields in the various retinas by taking the injection site as reference point (2 slices/retina; 3 fields/slice). Immunostainings were merged with bisbenzimide nuclear labelling (blue). The bar plots on the right (means±sem with superimposed individual data points) report the quantitative analysis of the integrated fluorescence intensity. Dystrophic retinas display higher densities of activated astrocytes, microglial cells and FGF2-positive cells compared to RCS-rdy, as a result of the ongoing degeneration. All the RCS groups show a similar density of GFAP/Iba-1/FGF2 positive cells demonstrating that the presence of either P3HT-NPs or Glass-NPs did not promote a significant tissue inflammatory reaction. *** p < 0.001, **** p > 0.0001, vs RCS-rdy controls; one-way ANOVA/Dunnett’s tests. Sample size (experimental animals) @ 30 DPI: GFAP 11, 10, 10, 11; Iba-1 11, 12, 12, 12; FGF2 8, 7, 7, 8; for RCSrdy, RCS, RCS + P3HT and RCS + Glass, respectively. Sample size (experimental animals) @ 240 DPI: GFAP 7, 6, 6, 7; Iba-1 8, 9, 8, 8; FGF2 4, 4, 4, 4; for RCSrdy, RCS, RCS + P3HT and RCS + Glass, respectively). For exact p values, see Supplementary Table 3. ONL, outer nuclear layer; INL, inner nuclear layer; GCL, ganglion cell layer. Scale bar, 50 μm.