Toxic effect of chloromycetin on the ultrastructures of the motor neurons of the Chinese tree shrew (Tupaia belangeri)

Can J Physiol Pharmacol. 2004 Apr;82(4):276-81. doi: 10.1139/y04-022.


This paper describes the toxic effects of chloromycetin on the motor neurons of the Chinese tree shrew (Tupaia belangeri chinensis) with horse radish peroxidase (HRP) as the labeling enzyme. When chloromycetin was administered orally at 2.5 mg/kg (body weight)/day for 3 days, Chinese tree shrews showed evidence of neurotoxicity. This included damage in cortical motor neuron synapses ending on neurons of the red nucleus and the ultrastructural changes in the mitochondria such as swelling of these organelles and blurring of their cristae. There was an increase of the mitochondrial matrix density and of the thickness of the synaptic membranes. These observations indicate that chloromycetin can lead to ultrastructural change of terminals of the cortical motor axons, and that Chinese tree shrews are sensitive animal model for chloromycetin neurotoxicity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Animals
  • Anorexia / chemically induced
  • Chloramphenicol / administration & dosage
  • Chloramphenicol / adverse effects*
  • Chloramphenicol / blood
  • Drug Administration Schedule
  • Drug Evaluation, Preclinical / methods
  • Drug-Related Side Effects and Adverse Reactions / chemically induced*
  • Female
  • Horseradish Peroxidase
  • Male
  • Microscopy, Electron / instrumentation
  • Microscopy, Electron / methods
  • Mitochondria / drug effects
  • Mitochondria / pathology
  • Mitochondria / ultrastructure
  • Motor Neurons / drug effects*
  • Motor Neurons / pathology
  • Motor Neurons / ultrastructure*
  • Neurotic Disorders / chemically induced
  • Red Nucleus / pathology
  • Red Nucleus / ultrastructure
  • Synaptic Membranes / drug effects
  • Synaptic Membranes / ultrastructure
  • Synaptic Vesicles / drug effects
  • Synaptic Vesicles / ultrastructure
  • Time Factors
  • Tupaiidae / physiology*


  • Chloramphenicol
  • Horseradish Peroxidase