title: Autophagy-mediated stress response in motor neuron after transient ischemia in rabbits.
abstract: OBJECTIVE
  Spinal cord injury is considered to be related to a vulnerability of spinal motor neurons to ischemia. However, the mechanisms underlying this vulnerability are not fully understood. We investigated the role of autophagy, which is an intracellular bulk degradation process, at motor neuron as a potential mechanism of neuronal death by immunohistochemical analysis for microtubule-associated protein light chain3 (LC3) and gamma-aminobutyric-acid type-A-receptor-associated protein (GABARAP) which are considered as markers of autophagy.
  
  
  METHODS
  We used a rabbit spinal cord ischemia model with the use of a balloon catheter. The spinal cord was removed at 8 hours, 1, 2, or 7 days after 15 minutes of transient ischemia, and histologic changes were examined with hematoxylin-eosin staining. Western blot analysis for LC3 and GABARAP, temporal profiles of LC3 and GABARAP immunoreactivity, and double-label fluorescence immunocytochemical studies were performed.
  
  
  RESULTS
  In the ischemia group, about 85% of motor neurons were preserved until 2 days after reperfusion, but were selectively lost at 7 days (P < .001 compared with sham group). Western blot analysis demonstrated slight immunoreactivity for LC3 and GABARAP in the sham-operated spinal cords. In contrast, the ischemia group LC3 and GABARAP immunoreactivity became apparent at 8 hours after reperfusion. With quantitative analysis we found that ischemia affected expression profiles of LC3-II and GABARAP. At 8 hours after reperfusion, co-labeling of LC3 and GABARAP were observed in the same motor neurons that eventually died.
  
  
  CONCLUSIONS
  These data suggest that autophagy was induced in motor neurons by transient spinal cord ischemia in rabbits.
authors.affiliation: Department of Cardiovascular Surgery, Kyushu University Graduate School of Medicine, Fukuoka, Japan. hironbab@heart.med.kyushu-u.ac.jp
authors.forename: Hironori
authors.initials: H
authors.lastname: Baba
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sakurai
authors.forename: Koji
authors.initials: K
authors.lastname: Abe
authors.forename: Ryuji
authors.initials: R
authors.lastname: Tominaga
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D007124:Immunoenzyme Techniques; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D009046:Motor Neurons / Q000378:metabolism* / Q000473:pathology; D011817:Rabbits; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism; D020760:Spinal Cord Ischemia / Q000378:metabolism* / Q000503:physiopathology*; D018709:Statistics, Nonparametric
chemical_list: D008869:Microtubule-Associated Proteins