title: Potential long-term benefits of acute hypothermia after spinal cord injury: assessments with somatosensory-evoked potentials.
abstract: OBJECTIVE
  Neuroprotection by hypothermia has been an important research topic over last two decades. In animal models of spinal cord injury, the primary focus has been assessing the effects of hypothermia on behavioral and histologic outcomes. Although a few studies have investigated electrophysiological changes in descending motor pathways with motor-evoked potentials recorded during cooling, we report here hypothermia induced increased electrical conduction in the ascending spinal cord pathways with somatosensory-evoked potentials in injured rats. In our experiments, these effects lasted long after the acute hypothermia and were accompanied by potential long-term improvements in motor movement.
  
  
  METHODS
  Laboratory investigation.
  
  
  METHODS
  University medical school.
  
  
  METHODS
  Twenty-one female Lewis rats.
  
  
  METHODS
  Hypothermia.
  
  
  RESULTS
  All animals underwent spinal cord contusion with the NYU-Impactor by a 12.5-mm weight drop at thoracic vertebra T8. A group (n = 10) was randomly assigned for a systemic 2-hr hypothermia episode (32 ± 0.5°C) initiated approximately 2.0 hrs postinjury. Eleven rats were controls with postinjury temperature maintained at 37 ± 0.5°C for 2 hrs. The two groups underwent preinjury, weekly postinjury (up to 4 wks) somatosensory-evoked potential recordings and standard motor behavioral tests (BBB). Three randomly selected rats from each group were euthanized for histologic analysis at postinjury day 3 and day 28. Compared with controls, the hypothermia group showed significantly higher postinjury somatosensory-evoked potential amplitudes with longer latencies. The BBB scores were also higher immediately after injury and 4 wks later in the hypothermia group. Importantly, specific changes in the Basso, Beattie, Bresnahan scores in the hypothermia group (not seen in controls) indicated regained functions critical for motor control. Histologic evaluations showed more tissue preservation in the hypothermia group.
  
  
  CONCLUSIONS
  After spinal cord injury, early systemic hypothermia provided significant neuroprotection weeks after injury through improved sensory electrophysiological signals in rats. This was accompanied by higher motor behavioral scores and more spared tissue in acute and postacute periods after injury.
authors: Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors: Anil
authors: A
authors: Maybhate
authors: Charles
authors: C
authors: Hu
authors: Faith A
authors: FA
authors: Bazley
authors: Qilu
authors: Q
authors: Yu
authors: Nitish V
authors: NV
authors: Thakor
authors: Candace L
authors: CL
authors: Kerr
authors: Angelo H
authors: AH
authors: All
mesh_terms: D000818:Animals; D001831:Body Temperature; D004195:Disease Models, Animal; D004567:Electrodes, Implanted; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D007036:Hypothermia, Induced / Q000379:methods*; D009416:Nerve Regeneration / Q000502:physiology; D011897:Random Allocation; D051381:Rats; D011917:Rats, Inbred Lew; D020127:Recovery of Function; D012016:Reference Values; D018570:Risk Assessment; D013119:Spinal Cord Injuries / Q000175:diagnosis* / Q000628:therapy*; D016896:Treatment Outcome