title: Effect of mechanical compression on the lumbar nerve root: localization and changes of intraradicular inflammatory cytokines, nitric oxide, and cyclooxygenase.
abstract: METHODS
  Investigation of intraradicular inflammation induced by mechanical compression.
  
  
  OBJECTIVE
  To investigate the mechanism of nerve root pain, this study used a lumbar nerve root compression model.
  
  
  BACKGROUND
  The manifestation of pain at sites of inflammation has a close relationship with the release of mediators from macrophages. However, the mediators involved in inflammation of nerve roots as a result of mechanical compression remain almost unknown.
  
  
  METHODS
  In this study, the seventh lumbar nerve root of dogs was compressed with a clip for 3 weeks to observe the changes caused by compression. Immunohistochemistry was performed using the avidin-biotin-peroxidase complex method to observe the changes of T cells (CD45) and macrophages (Mac-1) after compression. Antibodies against as interleukin-1 (IL-1), tumor necrosis factor-alpha (TNF-alpha), inducible nitric oxide synthase (i-NOS), and cyclooxygenase (COX)-1 and 2 were used to examine the localization and changes of these mediators caused by nerve root compression.
  
  
  RESULTS
  In control animals, resident T cells were detected, but there were no macrophages. IL-1beta and COX-2 were positive in the Schwann cells and vascular endothelial cells, while COX-1 was detected in the vascular endothelial cells. However, no cells showed TNF-alpha or i-NOS positively. After nerve root compression, numerous T cells and macrophages appeared among the demyelinized nerve fibers. The macrophages were positive for IL-1beta, TNF-alpha, i-NOS, and COX-2.
  
  
  CONCLUSIONS
  Inflammatory cytokines, NO, and COX-2 may be deeply involved in radiculitis caused by mechanical compression, and these mediators seem to be important in the manifestation of root pain.
authors.affiliation: Department of Orthopaedics and Rehabilitation Medicine, Fukui University School of Medicine, Matsuoka, Fukui, Japan. kshigeru@fmsrsa.fukui-med.ac.jp
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Hisatoshi
authors.initials: H
authors.lastname: Baba
authors.forename: Kenzo
authors.initials: K
authors.lastname: Uchida
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Kokubo
authors.forename: Chikara
authors.initials: C
authors.lastname: Kubota
authors.forename: Syuuich
authors.initials: S
authors.lastname: Yamada
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Hidezo
authors.initials: H
authors.lastname: Yoshizawa
mesh_terms: D000818:Animals; D016207:Cytokines / Q000032:analysis / Q000096:biosynthesis*; D004285:Dogs; D008159:Lumbar Vertebrae / Q000737:chemistry / Q000378:metabolism / Q000473:pathology; D009408:Nerve Compression Syndromes / Q000378:metabolism / Q000473:pathology; D009569:Nitric Oxide / Q000032:analysis / Q000096:biosynthesis*; D011451:Prostaglandin-Endoperoxide Synthases / Q000032:analysis / Q000096:biosynthesis*; D011843:Radiculopathy / Q000378:metabolism* / Q000473:pathology; D013126:Spinal Nerve Roots / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D013314:Stress, Mechanical
chemical_list: D016207:Cytokines; D009569:Nitric Oxide; D011451:Prostaglandin-Endoperoxide Synthases