Tissue nonheme iron contents in BALB/c fch/fch mice and their control littermates. (A) Tissue nonheme iron per gram weight tissue was measured in liver, spleen, kidney, and heart of wild-type (▪) or fch/fch (□) 12- to 14-week-old females. (B) Total iron content in each organ calculated as tissue nonheme iron content per weight of tissue × organ weight. Total iron contents in fch/fch compared with wild-type were significantly decreased in liver, kidney, and heart and increased in spleen, leading to a redistribution of iron from the organs to the spleen in fch/fch mice. Mean ± SD is shown for 6 mice per genotype. Asterisks indicate the significance of the influence of the fech mutation on the modifications of each parameter (*P < .01; **P < .001; n.s., not significant). (C) Perls staining of the spleens of BALB/c wild-type and fch/fch mice. Comparable intensity of the iron stain is observed in fch/fch mice compared with their wild-type littermates, associated with regular iron coloration, more condensed in the perifollicular zone surrounding the white pulp follicle. Original magnification, × 25. Images were taken with a 10×/0.1 PL Fluotar objective lens attached to a DMRB microscope (Leica Microsystems). The numerical aperture of the lens was 10×/0.30. Image digitization was performed with a Tri CCD Sony camera (Sony) with TRIBVN ICS Software (TRIBVN, Châtillon, France). Images were processed using Adobe Photoshop 5.0. wp indicates white pulp; pz, perifollicular zone; gc, germinal center; Ta, T lymphocyte area. (D) Electron microscopy of the spleen from a fch/fch mouse. At this low magnification, several spleen cells are visible. M indicates macrophage; L, lymphocyte; N, neutrophil. Original magnification, × 3000. Electron-dense intracytoplasmic vesicles containing iron deposits are visible in macrophages (arrows), especially at higher magnification (inset; original magnification, × 10 000).