Transgenic models of nerve repair and nerve regeneration

Objective: The mainstays of peripheral nerve research have historically involved quantifying nerve regeneration by the staining of fixed specimens at multiple time points and by assessing the function of innervated targets. We review advances in transgenic techniques that significantly improve upon standard nerve imaging. Methods: The emergence of transgenic mice whose axons or Schwann cells constitutively express chromophores and techniques enabling direct visualization of nerve regeneration over time after a nerve injury are evaluated. Results: These techniques have enabled investigators to monitor the behaviors of single axons after injury over time. Discussion: Transgenic tools that overexpress proteins or desired factors at certain targets are available, thus circumventing methodological difficulties in drug delivery, maintenance of constant neurotrophic factor concentrations and the comorbidities associated with achieving these aims. In this chapter, we will outline the advancements made in peripheral nerve research using transgenic mouse models. We focus on transgenic tools that have fluorescing nervous system components, overexpress factors at desired targets, or knockout mice with hereditable or modifiable deficits.