Fig. 1: Wound contraction and associated wound healing response in three adult injury models in the absence (spontaneous healing) and presence of a DRT graft. | npj Regenerative Medicine

Fig. 1: Wound contraction and associated wound healing response in three adult injury models in the absence (spontaneous healing) and presence of a DRT graft.

From: Mammals fail to regenerate organs when wound contraction drives scar formation

Fig. 1

ae guinea pig full-thickness excised skin wound. fj fully transected rat sciatic nerve. ko excised rabbit conjunctival stroma. a, f, and k Schematic of the corresponding injury site model. b, d, g, i, l, and n Immunohistochemical localization of αSMA+ myofibroblasts (red brown) 10 days after skin injury (b, d)20, 7 days after peripheral nerve transection (g, i)20, or 14 days after conjunctiva injury (l, n)27. b, g, and l Lack of DRT grafting or grafting with control grafts led to large, dense, highly-aligned MFB configurations. d, i, and n DRT grafting led to significantly fewer dispersed, and almost randomly aligned MFBs. Scale bars: skin and nerves, 100 μm; conjunctiva, 10 μm. c, e, h, j, m, and o Evaluating the structure of the resulting tissue. c, e In full-thickness skin wounds birefringence microscopy of collagen fibers demonstrates the formation of scar in ungrafted wounds (c) and the synthesis of the nearly-physiological dermis in DRT-grafted wounds (e)18,26,30. h In DRT-ungrafted peripheral nerve wounds electron microscopy reveals that 26 months following transection, the original nerve fibers have been replaced by a dense sheaf of collagen fibrils that enclose groups of Schwann cells (Büngner bands, Bb)32. j In contrast, histological micrographs of cross-sections from DRT-grafted peripheral nerve wounds demonstrate the formation of neural tissue whose histomorphometric (equivalent diameter, number of myelinated fibers, number of A-fibers) and electrophysiological assays were similar to those for the autograft31. m, o In conjunctiva wounds, immunohistochemical analysis and birefringence microcopy demonstrate scar formation in ungrafted wounds (m, note marked orientation of birefringent collagen fibers) and synthesis of near-normal conjunctival stroma collagen fibers (absence of orientation) in DRT-grafted wounds (o)27. Scale bars: skin, 50 μm; peripheral nerves, neural scar (top), 1 μm; peripheral nerve, regenerated nerve (bottom), 25 μm; conjunctiva, 50 μm. Figure 1a, f was reproduced with permission from Springer Nature29. Fig. 1b, d, g, i, and j were reproduced with permission from Biomaterials, 33, 4783–91, ©Elsevier (2012). Figure 1c, e were reproduced with permission from MIT30. Figure 1h was reproduced with permission from J. Anat., 192, 529–39, ©Wiley (1998). Figure 1l–o was reproduced with permission from Invest. Ophthalmol. Vis. Sci, 41, 2404–11, ©Association for Research in Vision and Ophthalmology (2000).

Back to article page