Effects of an <i>in Vitro</i> Reconstructed Three-dimensional Hematopoietic Microenvironment on Bone Regeneration in a Rat Calvarial Defect Model

Abstract

The regeneration of large bone defects is limited by reduced angiogenesis and cell migration from the remaining bone and tissue. Although scaff olds are required as autogenous bone grafts or artifi cial substrates for effi cient bone tissue engineering, cellular implants can also facilitate bone regeneration, and bone marrow is frequently applied to treat such defects. Here, we attempted to reconstruct a three-dimensional hematopoietic environment on a newly developed porous polyimide membrane using a modifi ed Dexter culture method and found that the membrane could maintain CD34-, CD45-, and TER-119-positive cells. We further applied membrane-enclosed, hematopoietic-lineage cells to a rat calvarial bone defect model to evaluate the eff ects of a multicellular environment on bone regeneration. Our results suggested that the cultured hematopoietic environment on the porous membrane facilitated new bone formation. The bone volume and bone mineral content values of the coculture group at 8 weeks post-surgery were signifi cantly higher than those in samples where only bone marrow stromal cells were used. Thus, coculture with multiple cell types accelerated bone formation, and culturing diverse cells on a membrane may facilitate cell transplantation in bone tissue engineering.