Experimental challenge for the treatment of Duchenne muscular dystrophy using a vascularized free muscle graft.

Following free vascularized normal muscle graft in mice, a study was made to determine whether dystrophin expression is possible in dystrophin-deficient muscles. In this study, dystrophic C57BL/10 ScSn-mdx mice were used as recipients and normal C57BL/10 ScSn mice as donors. A free vascularized quadriceps muscle 8.0 x 6.0 x 6.0 mm in size was orthotopically transplanted into a muscle defect produced in the recipient mouse. The diameter of the sutured vessels was about 0.4 mm. Transplantation was successful in 7 of 20 mice. At 12 weeks after the transplantation, the grafted muscle was examined by immunocytochemical stain using anti-dystrophin antibody. This study showed that dystrophin was expressed in the transplanted muscle but not in the adjacent recipient quadriceps muscle, suggesting that grafted donor cells with dystrophin failed to migrate into dystrophic muscle cells and fuse together. However, since the grafted normal skeletal muscle successfully survived and normal dystrophin was expressed in almost all the grafted muscle fibers, the possibility was suggested that the function of muscular dystrophy muscle can be compensated by complete replacement with a larger muscle.