title: The oxidative response in the chronic constriction injury model of neuropathic pain.
abstract: BACKGROUND
  In the chronic constriction injury model of rat neuropathic pain, oxidative stress as well as antioxidants superoxide dismutase and reduced glutathione (GSH) are important determinants of neuropathological and behavioral consequences. Studies of the chronic constriction injury model observed (indirect) signs of inflammation. We, therefore, investigated the level of oxidative stress and antioxidant enzymes in skeletal muscle tissue of the rat hind paw and (jugular vein) plasma at d 7 after nerve injury.
  
  
  METHODS
  The level of reactive oxygen and nitrogen species (RONS) was determined as a measure of oxidative stress. Reduced GSH levels and the ceruloplasmin/transferrin ratio were determined as measures of overall antioxidant activity. RONS and overall antioxidant activity were measured in skeletal muscle tissue of the hind paw and jugular vein plasma. The level of RONS in muscle was determined using spin trapping combined with electron paramagnetic resonance spectroscopy. Using electron paramagnetic resonance spectroscopy, we also determined plasma levels of transferrin and ceruloplasmin. GSH levels were determined using high-performance liquid chromatography.
  
  
  RESULTS
  In skeletal muscle tissue, the level of RONS was lower in nerve-injured hind paws than in controls. The plasma level (jugular vein) of RONS did not differ between nerve-injured and control rats. In skeletal muscle tissue, the level of GSH was higher in nerve-injured hind paws than in controls. The ceruloplasmin/transferrin ratio tended to be higher in (jugular vein) plasma of nerve-injured rats as compared to controls.
  
  
  CONCLUSIONS
  This study shows that, at d 7 after nerve injury, oxidative stress-induced changes are present also in skeletal muscle tissue of the rat hind paw. Our findings of a decreased level of RONS in combination with an increased level of the antioxidant GSH suggest that an overshoot of antioxidant activity overrules initial oxidative stress.
authors: Department of General Surgery, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. E.Tan@chir.umcn.nl
authors: Edward C T H
authors: EC
authors: Tan
authors: Soheyl
authors: S
authors: Bahrami
authors: Andrey V
authors: AV
authors: Kozlov
authors: Harry A J M
authors: HA
authors: Kurvers
authors: Henk J
authors: HJ
authors: Ter Laak
authors: Hans
authors: H
authors: Nohl
authors: Heinz
authors: H
authors: Redl
authors: R Jan A
authors: RJ
authors: Goris
mesh_terms: D000818:Animals; D002570:Ceruloplasmin / Q000378:metabolism*; D003251:Constriction, Pathologic; D005978:Glutathione / Q000378:metabolism*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology; D018384:Oxidative Stress; D051381:Rats; D017207:Rats, Sprague-Dawley; D026361:Reactive Nitrogen Species / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012585:Sciatica / Q000378:metabolism* / Q000473:pathology; D014168:Transferrin / Q000378:metabolism*
chemical_list: D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; D014168:Transferrin; D002570:Ceruloplasmin; D005978:Glutathione