Histological findings at 2 weeks after tendon-to-bone repair. (A) Repair only. (B) Repair + CS. (C) Repair + P407 (hematoxylin and eosin; magnification, ×100). Capillary proliferation as well as development and maturity of connective tissue were greater in the repair + P407 specimens than in the repair only and repair + CS specimens. Arrows indicate angiogenesis, and dashed arrows indicate mature collagen fibers. Scale bars, 100 μm. (D) Repair only. (E) Repair + CS. (F) Repair + P407 (immunohistochemical staining with rabbit monoclonal anti-CD34, ×200). Capillary proliferation was stained with a brown color and was marked in the repair + P407 specimens than in the repair only and repair + CS specimens. Scale bars, 200 μm.