Figure 1. Proton-induced X-ray emission (PIXE) microanalysis of iron and potassium in 2-, 3-, and 4-week-old rd10 and wild-type mouse retinas. A-B: Concentrations in μg/g dry weight of potassium (A) and iron (B) correspond to area of photoreceptor segments from 2-, 3-, and 4-week-old rd10 and wild-type (WT) mouse retinas. White bar represents WT mice and black bar rd10 mice. Values were means±SEM (n=7–11; *p<0.05, ** p<0.01, *** p<0.001; ns: not significant). C-F: Bidimensional maps represent potassium (C, E) and iron (D, F) distribution in 4-week-old WT (C-D) and rd10 (E-F) mice. Concentrations, expressed in counts per pixel, increase according to the color scale, from white to black. The different retinal layers were identified after staining with toluidine blue and are outlined with dotted lines. Dimension of the scan are 150×150 μm². Abbreviations: ch is choriocapillaris; inl is inner nuclear layer; ipl is inner plexiform layer; is is inner segments of photoreceptors; onl is outer nuclear layer; opl is outer plexiform layer; os is outer segments of photoreceptors; rpe is retinal pigmented epithelium; sc is sclera.