Influence of Alginates on Tube Nerve Grafts of Different Elasticity - Preliminary in Vivo Study

This preliminary research project has been conducted to evaluate different elastic polymer materials in terms of their applicability in peripheral nerve regeneration. Poly(tetrafluoroetylene-co-difluorovinylidene-co-propylene), poly(Llactide-co-D,L-lactide), and polyurethane were used for the manufacture of tubular implants. Alginate sodium gel and fibers were used as a scaffold to fill in tube nerve grafts and enhance nerve regeneration. The tubes were implanted to reconstruct a 10 mm gap in the sciatic nerve in rats. After 3, 7, 14, 28 days the tubes were retrieved for histological examination. Among tested tubes polyurethane implants were found to be the most suitable because of their mechanical and surgical properties. Other tested implants were found to be unfavorable due to their inappropriate rigidity, elasticity or surgical convenience. Alginate transformation into dense gel form was observed that hindered inner tube space cellular colonization. In consequence of this transformation nerve regeneration was inhibited inside tube nerve grafts. Histological examination showed massive colonization of the implants with Schwann cells, and growth of new axons was found within Schwann cells growing on tubes external surface. Appropriate time rates for alginate gelation and dissolveing must be determined to allow undisturbed tissue growth and maturation.