Chapter 21 - Peripheral Nerve Regeneration

Abstract

This chapter describes peripheral nerve regeneration. Regeneration after injury to the peripheral nerves may depend on the extent of injury to these membranes. If the endoneurial tube is intact after mild compression injury, then the axon regenerates smoothly and the synapse is reestablished in the area of the degenerated endplate. On the other hand, transection injury, in which a guidance or navigation tube is absent, results in delayed reinnervation of the muscle. Thus, to examine or facilitate nerve regeneration and subsequent reinnervation, it is important to understand the behavior of factors that are linked to degeneration. One of the main factors that contributes to degeneration and regeneration of peripheral nerves is the transport of axoplasm, which carries a wide range of substances, including proteins, membranous vesicles, neurotransmitters, lipids, mitochondria, and RNA. Approximately 70% of these nutrients are lost during transport from the neuronal cell body to the peripheral target. The speed of axoplasmic transport contributes to the rate of regeneration of the nerves. The fast axonal transport system is used to pass membrane-bound materials and depends on the availability of energy; it can be blocked by metabolic and energy system inhibitors. Inhibition of fast axonal transport, thus, interferes with synaptic transmission and, consequently, nerve regeneration of the axon.