Fibroblast growth factor effects on peripheral nerve regeneration in a silicone chamber model

We have developed a silicone nerve regeneration chamber that is partitioned into two compartments by a strip of nitrocellulose paper. The modified two-compartment chamber allows the investigation of the effects on rat sciatic nerve regeneration of trophic or growth factors that are initially bound to the nitrocellulose partition. In this study we compared the effects of untreated nitrocellulose, a siliconized nitrocellulose strip, and a strip that had been soaked in a basic fibroblast growth factor (FGF) solution. FGF is a known angiogenic factor and a mitogen for endothelial cells, fibroblasts, and Schwann cells. All of these cell types are present in the peripheral nerve. In vitro analyses, using 3T3 cells as test cells, showed that some of the bound FGF remained active on the nitrocellulose paper for at least 8-10 days. In vivo experiments, examined at 16 days post-implantation, revealed that spatial migration of all cellular elements (perineurial-like cells, vasculature, and Schwann cells) across the chamber gap was slower with untreated nitrocellulose strips than with siliconized strips but was most advanced with FGF-treated ones. Most striking was the well-developed vascular arborization of the regenerate within the FGF chambers. Histologic sections from the proximal one-half of the chamber revealed that the regenerate in untreated strip chambers consisted of fibrin matrix and erythrocytes, whereas a well-developed structure with all the cellular elements of a regenerating nerve was seen in several of the FGF strip chambers. We conclude that FGF stimulates peripheral nerve regeneration in this model.