A basic fibroblast growth factor slow‐release system combined to a biodegradable nerve conduit improves endothelial cell and Schwann cell proliferation: A preliminary study in a rat model

Abstract

A basic fibroblast growth factor (bFGF) slow-release system was combined to a biodegradable nerve conduit with the hypothesis this slow-release system would increase the capacity to promote nerve vascularization and Schwann cell proliferation in a rat model. Slow-release of bFGF was determined using Enzyme-Linked ImmunoSorbent Assay (ELISA). A total of 60 rats were used to create a 10 mm gap in the sciatic nerve. A polyglycolic acid-based nerve conduit was used to bridge the gap, either without or with a bFGF slow-release incorporated around the conduit (n = 30 in each group). At 2 (n = 6), 4 (n = 6), 8 (n = 6), and 20 (n = 12) weeks after surgery, samples were resected and subjected to histological, immunohistochemical, and transmission electron microscopic evaluation for nerve regeneration. Continuous release of bFGF was found during the observation period of 2 weeks. After in vivo implantation of the nerve conduit, greater endothelial cell migration and vascularization resulted at 2 weeks (proximal: 20.0 ± 2.0 vs. 12.7 ± 2.1, P = .01, middle: 17.3 ± 3.5 vs. 8.7 ± 3.2, P = .03). Schwann cells showed a trend toward greater proliferation and axonal growth had significant elongation (4.9 ± 1.1 mm vs. 2.8 ± 1.5 mm, P = .04) at 4 weeks after implantation. The number of myelinated nerve fibers, indicating nerve maturation, were increased 20 weeks after implantation (proximal: 83.3 ± 7.5 vs. 53.3 ± 5.5, P = .06, distal: 71.0 ± 12.5 vs. 44.0 ± 11.1, P = .04). These findings suggest that the bFGF slow-release system improves nerve vascularization and Schwann cell proliferation through the biodegradable nerve conduit.