Background: Traumatic muscle loss often results in poor functional restoration. Skeletal muscle injuries cannot be repaired without substantial fibrosis and loss of muscle function. Given its regenerative properties, the authors evaluated outcomes of fetal tissue-derived decellularized matrix for skeletal muscle regeneration. The authors hypothesized that fetal matrix would lead to enhanced myogenesis and suppress inflammation and fibrosis. Methods: Composite tissue composed of dermis, subcutaneous tissue, and panniculus carnosus was harvested from the trunk of New Zealand White rabbit fetuses on gestational day 24 and from Sprague-Dawley rats on gestational day 18 and neonatal day 3, and decellularized using a sodium dodecyl sulfate-based negative-pressure protocol. Six, 10-mm-diameter, full-thickness rat latissimus dorsi wounds were created for each treatment, matrix was implanted (excluding the defect groups), and the wounds were allowed to heal for 60 days. Analyses were performed to characterize myogenesis, neovascularization, inflammation, and fibrosis at harvest. Results: Significant myocyte ingrowth was visualized in both allogeneic and xenogeneic fetal matrix groups compared to neonatal and defect groups based on myosin heavy chain immunofluorescence staining. Microvascular networks were appreciated within all implanted matrices. At day 60, expression of Ccn2, Col1a1, and Ptgs2 were decreased in fetal matrix groups compared to defect. Neonatal matrix-implanted wounds failed to show decreased expression of Col1a1 or Ptgs2, and demonstrated increased expression of Tnf, but also demonstrated a significant reduction in Ccn2 expression. Conclusions: Initial studies of fetal matrices demonstrate promise for muscle regeneration in a rat latissimus dorsi model. Further research is necessary to evaluate fetal matrix for future translational use and better understand its effects.
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