Fig. 7

ECM-adherent UCB-NHSCs display a pluripotent phenotype and the capacity to regenerate skeletal muscle after cryoinjury. a ECM-adherent NHSCs were loaded onto Gelfoam or HA/TCP particles and implanted subcutaneously into immunodeficient mice. Implants were harvested after 8 weeks, processed for histological analysis, and stained with H&E (upper panels); Bielschowsky’s silver stain was used to identify nerve (see lower panel of “Nerve”) [26]. Sections were also immunostained for human nuclear ribonucleoprotein to confirm the origin of the cells responsible for neotissue formation (see middle row of panels except “bone”) [27]. Skeletal tissue (Bone) is only stained with H&E. Key to labels: a, artery; b, bone; c, capillary; e, endothelial cells; f, fat; g, gland; m, muscle; and n, nerve. b BM-MSCs were loaded onto Gelfoam carriers and implanted as controls. All procedures for experimental and control groups were performed at the same time. H&E stained sections demonstrated that BM-MSCs did not form heterogeneous tissues. c Histological cross sections of cryoinjured muscle tissue from immunodeficient mice treated with Matrigel alone (vehicle), Matrigel containing skin fibroblasts, or Matrigel containing extracellular matrix (ECM)-adherent umbilical cord blood (UCB) cells for 28 days. The perimeter of the wound is demarcated using dark blue dots. d Tissue morphology after H&E staining. UCB cells resulted in healing and a greater number of myogenic cells around the wound. Scale bar = 100 μm. e GFP-labelled UCB cells were injected into cryoinjured muscle to confirm that the cells were of human origin. Immunofluorescent (IF) staining demonstrated muscle regeneration by the labeled cells