Regeneration of critical size defects in calvaria of nude mice. (a) Masson trichrome staining (MT) of calvaria defects after 8 weeks shows bone in green and biphasic calcium phosphate (BCP) in gray. Scale bars: 2.5 mm and 500 μm for images in the left and right columns respectively. (b), (c) Histomorphometry of MT sections revealed that there was significantly more (aP <0.05) newly formed bone and bone marrow formed with the scaffolds of the BCP + BMSCs group compared with BCP discs without cells. BMSCs, bone marrow stromal cells.