Effects of Posttraumatic Hypothermia in an Animal Model of Traumatic Brain Injury(TBI) - Immunohistochemical Stain by TUNEL & β-APP -

실험적 외상성 뇌손상모델에서 외상 후 저체온법의 효과 - TUNEL과 β-APP Immunohistochemical Stain -

  • An, Byeong Kil (Department of Neurosurgery, College of Medicine, Inha University) ;
  • Ha, Young Soo (Department of Neurosurgery, College of Medicine, Inha University) ;
  • Hyun, Dong Keun (Department of Neurosurgery, College of Medicine, Inha University) ;
  • Park, Chong Oon (Department of Neurosurgery, College of Medicine, Inha University) ;
  • Kim, Joon Mee (Department of Anatomical Pathology, College of Medicine, Inha University)
  • 안병길 (인하대학교 의과대학 신경외과학교실) ;
  • 하영수 (인하대학교 의과대학 신경외과학교실) ;
  • 현동근 (인하대학교 의과대학 신경외과학교실) ;
  • 박종운 (인하대학교 의과대학 신경외과학교실) ;
  • 김준미 (인하대학교 의과대학 해부병리학교실)
  • Received : 1999.07.06
  • Accepted : 1999.10.05
  • Published : 2000.04.28

Abstract

Objective : Many investigators have demonstrated the protective effects of hypothermia following traumatic brain injury(TBI) in both animals and humans. It has long been recognized that mild to moderate hypothermia improves neurologic outcomes as well as reduces histologic and biochemical sequelae after TBI. In this study, two immunohistochemical staining using terminal deoxynucleotidyl-transferase-mediated biotin dUTP nick end labeling(TUNEL), staining of apoptosis, and ${\beta}$-amyloid precursor protein(${\beta}$-APP), a marker of axonal injury, were done and the authors evaluated the protective effects of hypothermia on axonal and neuronal injury after TBI in rats. Material and Method : The animals were prepared for the delivery of impact-acceleration brain injury as described by Marmarou and colleagues. TBI is achieved by allowing of a weight drop of 450gm, 1 m height to fall onto a metallic disc fixed on the intact skull of the rats. Fourty Sprague-Dawley rats weighing 400 to 450g were subjected to experimental TBI induced by an impact-acceleration device. Twenty rats were subjected to hypothermia after injury, with their rectal temperatures maintained at $32^{\circ}C$ for 1 hour. After this 1-hour period of hypothermia, rewarming to normothermic levels was accomplished over 30-minute period. Following 12 hours, 24 hours, 1 week and 2 weeks later the animals were killed and semiserial sagittal sections of the brain were reacted for visualization of the apoptosis and ${\beta}$-APP. Results : The density of ${\beta}$-APP marked damaged axons within the corticospinal tract at the pontomedullary junction and apoptotic cells at the contused cerebral cortex were calculated for each animal. In comparison with the untreated controls, a significant reduction in ${\beta}$-APP marked damaged axonal density and apoptotic cells were found in all hypothermic animals(p<0.05). Conclusion : This study shows that the posttraumatic hypothermia result in substantial protection in TBI, at least in terms of the injured axons and neurons.

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