Fig. 4: Curcumin treatment reduces the retinal degeneration preventing the RGC loss in our ex vivo model of retinal degeneration.

A–D Immunofluorescence analysis of retinal sections collected immediately after the sacrifice (T0), after 24 h after the sacrifice (T24), 24 h pre-treated with 5 μM (5 μM) and 10 μM (10 μM) of curcumin. IF images indicated a decrease of RGC NeuN-positive cells (green dots) in samples collected after 24 h from eye removal (B–B′) compared to time 0 (A–A′). The 5 μM (C–C′) as well as 10 μM (D–D′) of curcumin treatment was able to prevent the RGC loss detected at time 24. Nuclei were stained with the nuclear marker DAPI (blue). Scale Bar: 20 μm. A′, B′, C′, D′ High magnification of merged images. Scale bar: 40 μm. GCL ganglion cell layer, IPL inner plexiform layer, INL inner nuclear layer, OPL outer plexiform layer, ONL outer nuclear layer. E Quantification of the RGCs NeuN-positive (NeuN+) number showed a reduction of RGC NeuN+ in retinas collected at time 24 compared to time 0. Both 5 and 10 μM curcumin administration was able to reduce RGC loss, increasing significantly RGC NeuN+ cells number. F Representative western blot and relative densitometric quantification showed a reduction of NeuN level in retina homogenates collected at time 24 and a significant increased NeuN level induced by the 5 and 10 μM curcumin administrations. **P < 0.01 and ****P < 0.0001 [n = 5]. Data were expressed as mean ± SEM. One-way ANOVA, Tukey’s post hoc test.