Nerve regeneration across a 25-mm gap bridged by a polyglycolic acid-collagen tube: a histological and electrophysiological evaluation of regenerated nerves

Abstract

In the study reported here we have examined the nerve regeneration that occurs over a 25-mm gap using a novel biodegradable nerve guide tube. The tube was a composite of polyglycolic acid (PGA) mesh coated with collagen which was filled with neurotrophic factors. The left sciatic nerve of ten adult cats was dissected. The stumps were connected by the tube, and fixed gap. Histological examinations carried out 4-16 months after implantation of the tube revealed regeneration of well vascularized nerve tissue. Regeneration of both myelinated, unmyelinated axons and Schwann cells was confirmed by electron microscopy 5 months after surgery. Following injection of horseradish peroxidase (HRP) into a site peripheral to the regenerated segment of the sciatic nerves, motoneurons in the ventral horn of the spinal cord, afferent terminals in the medial portion of the dorsal column of the medulla oblongata, and sensory afferent nerve terminals in the dorsal horn of the spinal cord were labelled. Electrophysiological examinations revealed restoration of evoked electromyograms and sensory evoked potentials (SEPs) recorded from the cerebral cortex as well as the spinal cord. We also found that some of the regenerated motor axons exhibited branching in the regenerated segments. In two cases, a single motoneuronal axon from the regenerated side projected to both flexors and extensors, simultaneously. Our results indicate that the PGA-collagen composite tube is a promising tool for use as a nerve guide tube in peripheral nerve regeneration.

Types of neural guides and using nanotechnology for peripheral nerve reconstruction

“…Japanese researchers using polymeric PGA mesh and collagen sponge inside the tube could reconstruct a peripheral nerve gap of about 3 cm. 32,33 This structure is shown in Figure 6.…”

Schwann cells, neurotrophic factors, and peripheral nerve regeneration

“…29,30 Some of these have proved to be more potent in promoting peripheral nerve regeneration if Schwann cells were introduced. 30,31 Schwann cells play an indispensable role in promoting regeneration in three ways: first, by increasing their synthesis of surface cell adhesion molecules (CAMs), such as N-CAM, Ng-CAM/L1, N-cadherin, and L2/HNK-1; second, by elaborating basement membrane that contains many extracellular matrix proteins, such as laminin (LN), fibronectin (FN), heparan sulphate proteoglycans (HSP), and tenascin; and third, by producing many neurotrophic factors and their receptors.…”

Estudo experimental comparativo da ação das neurocinas cardiotrofina-1 e oncostatina-m na regeneração nervosa periférica

“…Apesar In spite of discordance (KIYOTANI et al, 1996;SUZUKI et al, 1999), several trials studied the axonal growth through empty tubes and concluded that 10 mm was the maximum distance to achieve an appropriate regeneration (BRUNELLI et al, 1994;DEN DUNNEN et al 1996;FRANCEL et al, 1997 (LUNDBORG et al 1982;WILLIAMS et al 1983;DA SILVA, 1987;LANGONE, 1991).…”