Figure 6. Working mechanism of metformin in the INFH rat model. (A) Immunohistochemical staining of ALPL, DMP1, vWF, and TRAP in the femoral head epiphysis. Black arrows indicate positive expression of vWF, a marker of endothelial cells of blood vessels. (B) Percentage of vascular density in the four groups. Vascular density (%) was calculated as vascular area stained by antibody for vWF-related antigen/total area of each image. Values are presented as the mean ± STD. (n = 4). *p < 0.01 versus Sham Control, #p < 0.01 versus INFH Control. (C) Number of TRAP-positive cells per unit area. Values are presented as the mean ± STD (n = 4). **p < 0.001 versus Sham Control, ##p < 0.001 versus INFH Control. Black bars = 50 μm.