Using macrophage cell culture to study the processes that result in removal of blood from bruises

Abstract

Macrophages are responsible for removing the extravasated blood that forms a bruise. Aspects of this process, such as how long it takes for erythrocytes to be phagocytosed and for iron to be demonstrated using Perls stain, are not established. This work sought to assess the possibility of using macrophages in cell culture to address some of the unknowns in the processes of resolution of a bruise. Human peripheral blood monocytes were obtained from buffy coats provided by the Australian Red Cross Blood Service. Monocytes were isolated by adherence to tissue culture plastic and differentiated into macrophages. Human blood clot was added with Dulbecco’s Modified Eagle Medium (DMEM) in combination with Fetal Calf Serum (FCS) and/or Heat inactivated human serum (HI HUS). After 24 hours the blood in the supernatant was washed off and replaced with fresh medium. It was noted red blood cells could be seen in macrophages. After 4 days, the macrophages showed prominent blue colour with Perls stain indicating the presence of hemosiderin. This pilot study has shown that in a cell culture system, macrophages can breakdown erythrocytes to produce hemosiderin. This model system may be used to investigate the processes behind resolution of bruises.