HO-1 participates in optimal iron re-utilization.

(A) H&E staining of the spleen sections from hmox^+/+ or hmox^+/− cell recipients at day 14 post-transplantation is shown. The arrows indicate hemosiderin-laden macrophages. The transplantation of HO-1-deficient BM cells leads to an increase of hemosiderin. The magnification is 400×. The photograph shown is a representative of three experiments. (B) Prussian blue iron staining of the spleen sections from hmox^+/+ or hmox^+/− cell recipients at day 14 post-transplantation is shown. The transplantation of HO-1-deficient BM cells leads to an increase of Prussian blue-positive cells. The magnification is 100×. The photograph shown is a representative experiment out of the three that were performed. (C) The total and free iron levels in the splenic homogenates from hmox^+/+ or hmox^+/− cell recipients at day 14 post-transplantation are shown. The transplantation of HO-1-deficient BM cells leads to a decrease of soluble iron. The mean ± SEM is shown for six mice per genotype; *P≤0.05.