Figure 9: Evaluation of changes in the expression of VEGF with osteogenesis in the presence or absence of collagen. (A) The fluorescence microscopy photograph shows a calcein and alizarin-labeled new bone front in the tunnel. (B) A light microscope photograph showing angiogenesis in tunnels stained with VEGF on same section of A. (C) A comparison (mm2/tunnel) of the area of angiogenesis (stained brown) per tunnel (inside of each yellow-dotted line) in 37H and Col37H (*p<0.01).