A method to reorganize the bone marrow-like tissue with suspension of bone marrow cells

To elucidate the mechanism of hematopoiesis and bone marrow (BM) diseases, the realization of BM three-dimensional (3D) culture system is very important. Because more than 90% of the BM cells are non-adherent blood cells, it is difficult to organize the dispersed-state BM cells with the conventional aggregation methods e.g. hanging drop method. The objective of this study is to reproduce the BM-like tissue from dispersed-state BM cells in vitro. We reported a method of forming aggregates using methylcellulose (MC) medium [1]. This method can make a 3D aggregation state rapidly regardless of adhesive property of the cells. This method applied to the BM cells, they gathered in 10 minutes and formed tissue-like spheroids within 24h. Formed BM-like tissue could remove from MC medium on the Day 1. By hematoxylin-eosin staining, the blood cells were maintained for 3 days. By staining with anti-CD68 antibody, macrophages in the BM-like tissue were found at the same frequency as those in the intact BM tissue. It was confirmed that mesenchymal cells, for example CXCL12⁺ reticular cells, PDGFRα⁺ cells were maintained in the BM-like tissues. From these results, the method using MC medium was suitable to reconstitute the BM-like tissue.