Effects of epidural hypothermic saline infusion on locomotor outcome and tissue preservation after moderate thoracic spinal cord contusion in rats.
OBJECTIVE
Regionally delivered hypothermia has advantages over systemic hypothermia for clinical application following spinal cord injury (SCI). The effects of local hypothermia on tissue sparing, neuronal preservation, and locomotor outcome were studied in a moderate thoracic spinal cord contusion model.


METHODS
Rats were randomized to four treatment groups and data were collected and analyzed in a blinded fashion. Chilled saline was perfused into the epidural space 30 minutes postcontusion to achieve the following epidural temperatures: 24 +/- 2.3 degrees C (16 rats), 30 +/- 2.4 degrees C (13 rats), and 35 +/- 0.9 degrees C (13 rats). Hypothermia was continued for 3 hours when a 45-minute period of rewarming was instituted. In a fourth group a moderate contusion only was induced in 14 animals. Rectal (core) and T9-10 (epidural) temperatures were measured continuously. Locomotor testing, using the Basso-Beattie-Bresnahan (Ba-Be-Br) scale, was performed for 6 weeks, and rats were videotaped for subsequent analysis. The lesion/preserved tissue ratio was calculated throughout the entire lesion cavity and the total lesion, spinal cord, and spared tissue volumes were determined. The rostral and caudal extent of gray matter loss was also measured. At 6 weeks locomotor recovery was similar in all groups (mean Ba-Be-Br Scale scores 14.88 +/- 3.71, 14.83 +/- 2.81, 14.50 +/- 2.24, and 14.07 +/- 2.39 [p = 0.77] for all four groups, respectively). No significant differences in spared tissue volumes were found when control and treatment groups were compared, but gray matter preservation was reduced in the infusion-treated groups.


CONCLUSIONS
Regional cooling applied 30 minutes after a moderate contusive SCI was not beneficial in terms of tissue sparing, neuronal preservation, or locomotor outcome. This method of cooling may reduce blood flow in the injured spinal cord and exacerbate secondary injury.
Casas
Carlos E
CE
The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami, Florida 33136, USA.
Herrera
Loren P
LP
Prusmack
Chad
C
Ruenes
Gladys
G
Marcillo
Alexander
A
Guest
James D
JD
D000704:Analysis of Variance; D000818:Animals; D001831:Body Temperature / Q000502:physiology; D003288:Contusions / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D005260:Female; D007036:Hypothermia, Induced / Q000379:methods*; D016014:Linear Models; D008124:Locomotion / Q000502:physiology*; D008991:Monitoring, Physiologic; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012965:Sodium Chloride / Q000008:administration & dosage*; D013116:Spinal Cord / Q000473:pathology*; D013119:Spinal Cord Injuries / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D014021:Tissue Preservation / Q000379:methods*; D016896:Treatment Outcome
D012965:Sodium Chloride