SDF-1β significantly increases 3-D bone morphometric parameters following BMSC tibial transplantation in irradiation-preconditioned recipients. 3-D bone morphometric paratmeters of the proximal tibia marrow space 4 weeks post-transplantation (ROI: starting immediately beyond the epiphyseal plate and extending 2 mm distally by transaxial tracing for 112 cuts). (A) Percent bone volume (BV/TV), (B) trabecular number (Tb.N), (C) trabecular thickness (Tb.Th), and (D) trabecular separation (Tb. Sp). Vehicle- and Tet-Off-SDF-1β (± Dox) or Tet-Off-EV BMSC-transplanted tibiae at 1.32 × 107 cells/ml (*p <0.05, **p <0.01, ***p <0.0001 BMSC-transplanted vs. vehicle controls; ap <0.05 Tet-Off-SDF-1β (−Dox) vs. Tet-Off-SDF-1β (+Dox) or Tet-Off-EV, n = 5/Tet-Off-SDF-1β (−Dox); n = 5/Tet-Off-SDF-1β (+Dox); n = 10/Tet-Off-EV).