MORPHOLOGICAL AND NEUROCHEMICAL ASSESSMENT OF REGENERATED PERIPHERAL NERVES IN BRIDGING CONDUITS

Abstract

This research evaluated the use of proteins associated with neurite outgrowth, synapse formation, and Schwann cell proliferation as surrogate measures for morphological measurement of rat sciatic nerve regeneration across a 10-mm gap in silicone rubber conduits (SRCs), genipin-crosslinked gelatin conduits (GGCs), and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC)/N-hydroxysuccinimide (NHS)-crosslinked gelatin conduits (ENGs). After eight weeks, axonal growth of regenerated nerves was determined using light microscopy and computer-based quantitative image analysis. Expression of the axonal growth-associated protein 43 (GAP-43), the synaptic protein synapsin I, and the transforming growth factors type β (TGF-βs) in regenerated nerves was assessed simultaneously by Western blot. As a result, the nerve regenerates in the SRCs and the ENGs had a significantly larger endoneurial area containing more myelinated axons compared to those in the GGCs at p < 0.05. The levels of GAP-43 and synapsin I, but not TGF-β, correlated well with axonal growth in the regenerated nerves. These data suggest that the combined techniques can be used to assess the status of regenerating axons in bridging conduits with different construction and physical properties.