Effects of mechanical stimulation on cell-embedded decellularized extracellular matrix patches for the treatment of muscle defects

Current therapeutical approaches to skeletal muscle defects, such as volumetric muscle loss, are based on the use of synthetic materials for surgical repair. However, synthetic patches can cause several side effects, including the inability to match physiological muscle growth and the risk of recurrence, with consequent multiple surgeries. To overcome these problems, decellularized extracellular matrix (dECM) has been recently tested in vitro as biological alternative for tissue replacement, being able to closely replicate the native tissue microenvironment by preserving the original structure and components. Moreover, dECM retains cell growth factors, which can enhance cell migration, proliferation, and differentiation, enabling skeletal muscle remodeling. In this study, dECM hydrogel patches were manufactured, enriched with human muscle cells and fibroblasts, and mechanically stimulated by applying a physiological strain protocol using a bioreactor. This approach can promote cell alignment and improve the maturation and regenerative capacity of patches, as muscle cells are sensitive to mechanical stimulation signals. The effects of patch culture and application of the mechanical stimulation were tested using Live/Dead assays, immunofluorescence analyses, and DNA amount quantification. The ultimate goal of this approach is to promote the alignment of muscle fibers according to the architecture of native tissue, therefore to enable its potential use in future skeletal muscle regeneration applications.