Fig. 5.

Histology of tibial nerve in individual nerve repair (INR) model. Tibial nerve distal to the nerve transection repair site was harvested, cut into semi-thin (1 μm) sections and stained with Toluidine Blue. Cross section images (400x) were used for comparison by light microscopy. A1, Left tibial naïve nerve untransected and vehicle-treated - numerous axons tightly packed and surrounded by distinct myelin sheaths; A2, Right tibial transected and repaired nerve vehicle-treated - fewer axons, less distinct, reduced myelination, reduced nerve fiber density, increased axonal degeneration, and some regenerating axons (small diameter). B1, Left tibial naïve nerve untransected and MSC treated – numerous axons tightly packed and surrounded by distinct myelin sheath as in A1; B2, Right tibial transected and repaired nerve MSC treated – increased large size axons, nerve fiber density, myelination and regenerating axons, and reduced axonal degeneration compared to vehicle-treated control A2. a, normal axons (axons visible as blue annulae with myelination evident); b, degenerating axons (axons less distinct, myelination decreased, and myelin debris evident); c, regenerating axons (axons visible with distinct myelination and more nerve fiber density); MSC, mesenchymal stem cells. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)