l-Theanine and NEP1-40 promote nerve regeneration and functional recovery after brachial plexus root avulsion

Biochem Biophys Res Commun. 2019 Jan 22;508(4):1126-1132. doi: 10.1016/j.bbrc.2018.11.124. Epub 2018 Dec 12.

Abstract

Brachial plexus root avulsion causes severe sequelae Treatments and prognosis face many problems, including inflammatory reaction, oxidative damage, and myelin related inhibitory effect. l-Theanine has anti-inflammatory, anti-oxidative, and neuroprotective effects. NEP1-40 competitively inhibits Nogo-66 receptor (NgR1) promotes axonal regeneration. Forty-eight Sprague-Dawley rats were randomly assigned into four groups to establish an animal model of brachial plexus root avulsion. Inflammation and oxidative damage were evaluated by spectrophotometry and motor function of the upper limbs was assessed via Terzis grooming test after modeling. Immunofluorescence and hematoxylin and eosin staining were utilized to determine the content of reactive oxygen species, activation of microglial cells, neuroprotection, and nerve regeneration. Compared with the control group, the L-Theanine + NEP1-40 group had significantly decreased myeloperoxidase, malondialdehyde, interleukin-6, reactive oxygen species, and microglial cells, significantly increased score on the Terzis grooming test, increased motor neuron content, and thickened muscle fibers, increased area, and appearance of large and clear motor endplate structures. The results of this study suggest that l-Theanine combined with NEP1-40significantly promoted nerve regeneration after brachial plexus root avulsion, and may be a potential treatment for promoting nerve regeneration. Possible mechanisms underlying these results are alleviation of oxidative damage and inflammatory responses in the injured area and antagonism of myelin inhibition.

Keywords: Brachial plexus root avulsion; Inflammatory response; Myelin-associated inhibitors; Nerve regeneration; Oxidative damage; Transitional zone.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anterior Horn Cells / drug effects
  • Anterior Horn Cells / metabolism
  • Anterior Horn Cells / pathology
  • Brachial Plexus / drug effects
  • Brachial Plexus / injuries*
  • Brachial Plexus / pathology
  • Brachial Plexus / physiopathology*
  • Cell Survival / drug effects
  • Drug Therapy, Combination
  • Female
  • Glutamates / pharmacology
  • Glutamates / therapeutic use*
  • Interleukin-6 / metabolism
  • Malondialdehyde / metabolism
  • Microglia / drug effects
  • Microglia / metabolism
  • Motor Endplate / drug effects
  • Motor Endplate / physiopathology
  • Motor Neurons / drug effects
  • Motor Neurons / metabolism
  • Motor Neurons / pathology
  • Muscle Fibers, Skeletal / drug effects
  • Muscle Fibers, Skeletal / metabolism
  • Nerve Regeneration / drug effects*
  • Peptide Fragments / pharmacology
  • Peptide Fragments / therapeutic use*
  • Peroxidase / metabolism
  • Radiculopathy / drug therapy*
  • Radiculopathy / pathology
  • Radiculopathy / physiopathology*
  • Rats, Sprague-Dawley
  • Reactive Oxygen Species / metabolism
  • Recovery of Function / drug effects*
  • Spinal Cord / drug effects
  • Spinal Cord / metabolism
  • Spinal Cord / pathology
  • Spinal Cord / physiopathology

Substances

  • Glutamates
  • Interleukin-6
  • Peptide Fragments
  • Reactive Oxygen Species
  • Malondialdehyde
  • theanine
  • Peroxidase