Figure 9.

Balloon injury promotes red blood cell phagocytosis. Rats were either subjected to intravenous injections of senescent RBCs once a week for 2 weeks or were not. Subsequently, a subset of the rats was submitted to ballooning of the abdominal aorta. [line (A)] Aorta from a rat injected with senescent RBCs without ballooning. Masson’s trichrome staining (A1) of the aorta associated with an adjacent lymph node. Areas positive for Perls + DiAminoBenzidin (DAB) stainig (A2, A2′) were observed throughout the media, indicating the presence of redox-active iron (negative for Perls or DAB alone, not shown). Perls staining (A3, A3′) revealed a continuum of iron transport and metabolism between the arterial wall and the local LN. (B) Aorta of a rat injected with senescent RBCs after ballooning. Masson’s trichrome staining (B1) showing intimal proliferation. Perls + DAB staining (B2, B2′) indicating the presence of redox-active iron in the intima and media. Perls alone staining (B3), showing an accumulation of ferric iron (sequestered form potentially linked to ferritin) in the arterial wall. (C) Concentrations (logarithmic scale) of iron in the aortas of different groups of rats following senescent RBC injections, ballooning and/or splenectomy (n = 10 for each group), as determined by spectrophotometry. *p < 0.05 and **p < 0.01; Mann–Whitney’s test.