Allogeneic Decellularized Muscle Scaffold Is Less Fibrogenic and Inflammatory than Acellular Dermal Matrices in a Rat Model of Skeletal Muscle Regeneration

Background: Skeletal muscle trauma can produce grave functional deficits, but therapeutic options remain limited. The authors studied whether a decellularized skeletal muscle scaffold would provide benefits in inducing skeletal muscle regeneration over acellular dermal matrices. Methods: Eighty-two rat muscle defects were surgically created and assigned to no intervention or implantation of AlloDerm, Strattice, decellularized rat muscle, or decellularized rat dermis to 30 or 60 days. Decellularized rat muscle and dermis were prepared using a negative pressure-assisted protocol. Assessment for cellularity, neovascularization, myogenesis, inflammation and fibrosis were done histologically and by polymerase chain reaction. Results: Histology showed relative hypercellularity of AlloDerm (p < 0.003); Strattice appeared encapsulated. Immunofluorescence for CD31 and myosin heavy chain in decellularized rat muscle revealed dense microvasculature and peripheral islands of myogenesis. MyoD expression in muscle scaffolds was 23-fold higher than in controls (p < 0.01). Decellularized rat muscle showed no up-regulation of COX-2 (p < 0.05), with less expression than decellularized rat dermis and Strattice (p < 0.002). Decellularized rat muscle scaffolds expressed tumor necrosis factor-α less than Strattice, AlloDerm, and decellularized rat dermis (p < 0.01); collagen-1a less than decellularized rat dermis and Strattice (p < 0.04); α-smooth muscle actin 7-fold less than AlloDerm (p = 0.04); and connective tissue growth factor less than Strattice, AlloDerm, and decellularized rat dermis (p < 0.02). Conclusion: Decellularized muscle matrix appears to reduce inflammation and fibrosis in an animal muscle defect as compared with dermal matrices and promotes greater expression of myocyte differentiation-inducing genes.