Role of persisting basement membrane in the reorganization of myofibres originating from myogenic cell grafts in the rat

Abstract

Satellite cells grafted at the site of an irreversible muscle injury regenerate normal myofibres that become organized in fascicles. The role of the basement membrane in organization of the newly formed muscle fibres was investigated using polyclonal antibodies against laminin, fibronectin, type IV collagen and heparan sulphate proteoglycan. In ungrafted muscles, original basement membranes were reactive to these antibodies at 7, 14 and 45 days after injury. Labelling of satellite cells with FITC-latex beads showed the labelled myoblasts and new myofibres within the remnants of old basement membranes at 7 days after cell implantation and thereafter. Electron microscopy of injured-ungrafted muscles showed persistence of electron dense material corresponding to thin layers of old basal laminae partially interrupted. After cell grafting, myotubes developed within these structures and were surrounded by redundant basal laminae. These results suggest that grafted cells are able to migrate inside the basement membranes which serve as scaffolding for their development.