FIG. 6.

Surgical repair of VML with muscle-derived rat extracellular matrix (RAMM). Unrepaired (A, C, E, G) and RAMM-repaired (B, D, F, H) TA muscles harvested 2 months after injury were analyzed using immunohistochemistry. (A, B) Regenerating myosin-positive muscle fibers (white arrows) in isolation from the remaining muscle mass were only observed in the defect area of RAMM-repaired muscles. (C, D) Collagen I deposition was prominent in the defect area of both unrepaired and RAMM-repaired muscle. However, the extent of collagen 1 deposition was qualitatively greater in RAMM-repaired muscle [area to left of yellow line is fascia, between lines is scar tissue, and to right of white line is muscle remaining muscle mass; no fascia is depicted in (D)]. (E, F) Macrophages (CD68) were present in the remaining muscle mass (yellow arrows) or in the area of collagen 1 deposition in the defect area (white arrows). The area to the left of the yellow line in E is fascia. (G, H) Vascularization (white arrows) in the defect area was detected using von Willebrand (vWF) staining. Nuclei were stained with DAPI. Stains are identified for each slide with color coded text in the left margin of each row; WG, wheat germ agglutinin. Scale bars=50 μm. (I) Rats were perfused with Indian ink at 3, 7, or 14 days after implantation of RAMM to demonstrate an integrated vascular network with the host circulation.