Absence of muscle regeneration after implantation of a collagen matrix seeded with myoblasts

Collagens are widely used as biomaterials for e.g. soft tissue reconstructi on. The present study was aimed at reconstruction of abdominal wall muscle using processed dermal sheep collagen (DSC) and myoblast seeding. Myoblasts were harvested from foetal quadriceps muscle of an inbred rat strain, cult ured, seeded as non-differentiated cells into DSC-discs and incubated in vi tro for 2 h. The discs were implanted in the abdominal wall defects in adul t rats. Non-seeded discs functioned as control. Implantation periods till w eek 6 were chosen. At day 1 and 2 after implantation infiltration of granul ocytes and macrophages was clearly more intense in the seeded discs than in the controls. Relatively large numbers of mast cells infiltrated from the side of the adhering omentum. In central areas of the discs, seeded cells w ere easily recognized till day 5, since non-seeded control discs did not co ntain such cells. Ingrowth of host cells and tissue at the margins proceede d faster with the seeded discs. Lymphocyte accumulations were observed in t he 3 week seeded specimen. At week 3 and week 6, in the seeded discs muscle tissue was not present, in contrast to very large giant-like cells. It is concluded that the chosen method of myoblast seeding did not result in the regeneration of muscle during this observation period. Unfavorable circumst ances such as humoral factors, direct cellular interactions (phagocytosis), indirect cellular interactions (cytokines), or initial absence of vascular ization, may play a role. Further studies are required. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.