Muscle-derived decellularised extracellular matrix improves functional recovery in a rat latissimus dorsi muscle defect model.

PURPOSE: Craniofacial maxillary injuries represent nearly 30% of all battlefield wounds, often involving volumetric muscle loss (VML). The physical loss of muscle results in functional deficits and cosmetic disfigurement. Although surgical solutions are limited, advances in biomaterials offer great promise for the restoration of form and function following VML. The primary purpose of this study was to determine whether muscle function could be restored in a novel VML rat model using muscle-derived extracellular matrix (M-ECM).

METHODS: Ten percent of the mass of the latissimus dorsi (LD) was excised. Three groups were examined: 1) no repair of defect (DEF), 2) repair with M-ECM and 3) sham (all procedures except muscle excision). Four and 8 weeks post-surgery, the isometric contractile properties of the LD were assessed in situ and selected histological properties were evaluated.

RESULTS: The defect resulted in an initial reduction in peak isometric force (Po) of 30%. At 8 weeks the difference between DEF and sham was 20.5%. At the same time, M-ECM was only 8.4% below sham. Although the histological analysis revealed a narrow, but well-formed band of muscle running along the middle of the M-ECM, it was judged to be too small to account for the observed improvement in muscle force.

CONCLUSIONS: Repair of VML with M-ECM can dramatically improve muscle function independent of muscle regeneration by providing a physical bridge that accommodates force transmission across the injury site. This method of repair may provide an easily translatable surgical method for selected forms of VML.