Rat aorta isografts possess nerve regeneration-promoting properties in silicone Y chambers

Recent investigations using synthetic entubation materials have demonstrated that nerve regeneration across a gap requires peripheral nervous tissue as a distal component within the chamber. Regeneration fails if the distal end of the regeneration chamber remains open to the environment, or is filled with tendon or skin. These results are contrary to those of Weiss and Taylor (1944) who used homologous aorta as a chamber material and found that regeneration was successful across a gap regardless of the distal tissue, even in the branches of the aorta that were closed or open. In the present report, silicone Y chambers were implanted with the distal branch remaining open, or filled with pieces of nerve, tendon, or isologous aorta. A homogenous fibrin matrix formed in all the chamber branches by 1 week postimplantation. At 4 weeks, regeneration across a 10-mm gap failed in the chamber branches that were open or filled with tendon. However, regeneration was successful in those branches containing aorta or nerve. These experiments strongly support the hypothesis that aorta tissue, like peripheral nervous tissue, is a source of regeneration-promoting materials. The results provide a probable explanation for and a reconciliation of the discrepancies between the earlier observations of Weiss and Taylor and those of more recent investigators.