Destruction of osteoblastic niche during GVHD. (A-B) Histopathology of BM in [B6→BDF₁] transplantation model (n = 3 in each group; more than 5 sections per mouse were analyzed). (A) Arrows indicate osteoblasts (magnification ×400). (B) Staining for alkaline phosphatase (ALP) activity was performed on day 8 after allo-HSCT (magnification ×20). (C) Calcein double labeling and toluidine blue staining of tibiae in recipient mice (“Histopathologic analysis, immunofluorescence staining, and histomorphometric analysis”). Arrows indicate osteoblasts. (D) Real-time RT-PCR analysis of crushed whole tibia on day 14. Osteoblast differentiation markers Runx2, Twist, Msx2, Osterix, Dlx5, and osteocalcin were analyzed. Data are mean and SE (n = 4). Experiments were performed at least twice. *P < .05, vs untreated control group.