Myoblast-acellular skeletal muscle matrix constructs guarantee a long-term repair of experimental full-thickness abdominal wall defects

To obtain a valuable treatment of congenital muscle defect, cell-matrix constructs composed of satellite cell-derived myoblasts (XY karyotype) seeded on muscle acellular matrices were used to repair a previously created full-thickness defect of abdominal wall of 18 1-month-old female Lewis rats. Acellular abdominal matrices, obtained by a detergent-enzymatic method, were positive for both basic fibroblast growth factor and transforming growth factor-beta, and were able to support in vitro cell adhesion. All animals survived the surgery, without signs of infection or implant rejection, and were humanely killed at 1, 3, or 9 months after surgery. The implants appeared well preserved, were integrated in the host tissue, and maintained their original dimension and thickness until 9 months. Vesicular acetylcholine transporter was expressed on the surface of muscle fibers from 1 month postsurgery. Finally, implanted male myoblasts were present inside the patches until 9 months, as demonstrated by the expression of SrY mRNA and by the presence of Y chromosome probe signal. These results allow us to conclude that cell-matrix constructs could represent a promising approach to the repair of muscle defects, because they are repopulated in vivo by skeletal muscle cells and nervous elements and maintain their structural integrity over the long term.