Bone regeneration by BMP-2 enhanced adipose stem cells loading on alginate gel

Adipose stem cells (ASCs) have the potential to differentiate into a variety of cell lineages both in vitro and in vivo. In this study, ASCs were harvested from normal Sprague-Dawley (SD) rats and transfected by BMP-2 gene before they were loaded on alginate. The ability of bone regeneration was determined in rat critical-size cranial defects. An 8-mm diameter defect was created in the calvarias of 36 rats; these rats were divided into three groups. In experimental group, the defects were filled with alginate gel combined with BMP-2 transfected ASCs; in negative control group, the defects were filled with alginate gel mixed with normal ASCs; in blank controls, the defects were filled with cell-free alginate gel. Four rats of each group were killed and the cranial defect sites were observed at 4, 8 and 16 weeks after surgery. There was complete repair of cranial defects in experimental group using the alginate gel loading BMP-2 transfected ASC, but only partial repair in negative controls and in the blank control. The engineering approach combining BMP-2 enhanced ASCs with alginate gel can therefore stimulate bone regeneration and repair for the large size bone defects.