Photofabricated gelatin-based nerve conduits:: Nerve tissue regeneration potentials

There is a strong demand for development of nerve guide conduit with prompt nerve regeneration potential for injury-induced nerve defect. Prior to study on nerve tissue engineering using Schwann cells or nerve stem cells, the effectiveness of photofabricated scaffolds based on photocurable gelatin was examined. This study describes the evaluation of in vivo nerve tissue regeneration potentials of three custom-designed and -fabricated prostheses (inner diameter, 1.2 mm; outer diameter, 2.4 mm; wall thickness, 0.60 mm; and length, 15 mm) made of photocured gelatin: a plain photocured gelatin tube (model 1), a photocured gelatin tube packed with bioactive substances (laminin, fibronectin, and nerve growth factor) coimmobilized in a photocured gelatin rod (model 11), and a photocured gelatin tube packed with bioactive substances coimmobilized in multifilament fibers (model 111). These prostheses were implanted between the proximal and distal stumps 10 mm of the dissected right sciatic nerve of 70 adult male Lewis rats for up to I year. The highest regenerative potentials were found using the model III prosthesis, followed by the model 11 prosthesis. Markedly retarded neural regeneration was observed using the model I prosthesis. These were evaluated from the viewpoints of functional recovery, electrophysiological responses, and tissue morphological regeneration. The significance of the synergistic cooperative functions of multifilaments, which serve as a platform that provides contact guidance to direct longitudinal cell movement and tissue ingrowth and as a cell adhesive matrix with high surface area, and immobilized bioactive substances, which enhance nerve regeneration via biological stimulation, is discussed.