Post-traumatic moderate systemic hypothermia reduces TUNEL positive cells following spinal cord injury in rat.
METHODS
A standardized animal model of contusive spinal cord injury (SCI) with incomplete paraplegia was used to test the hypothesis that moderate systemic hypothermia reduces neural cell death. Terminal deoxynucleotidyl transferase [TdT]-mediated deoxyuridine triphosphate [dUTP] nick-end labeling (TUNEL) staining was used as a marker of apoptosis or cell damage.


OBJECTIVE
To determine whether or not moderate hypothermia could have a neuroprotective effect in neural cell death following spinal cord injury in rats.


METHODS
Kagawa Medical University, Japan.


METHODS
Male Sprague-Dawley (SD) rats (n=39) weighing on average 300 g (280-320 g) were used to prepare SCI models. After receiving contusive injury at T11/12, rats were killed at 24 h, 72 h, or 7 days after injury. The spinal cord was removed en bloc and of examined at five segments: 5 and 10 mm rostral to the center of injury, center of injury, and 5 and 10 mm caudal to the center of injury. Rats that received hypothermia (32 degrees C/4 h) were killed at the same time points as those that received normothermia (37 degrees C/3 h). The specimens were stained with hematoxylin and eosin, and subjected to in situ nick-end labeling (TUNEL), a specific method for visualizing cell death in the spinal cord.


RESULTS
At 24 h postinjury, TUNEL positive cells (TPC) decreased significantly 10 mm rostral to center of injury in hypothermic animals compared to the normothermia group. At 72 h post-SCI, TPC also decreased significantly at 5 mm rostral, and 5 and 10 mm caudal to the lesion center compared to normothermic animals. At 7 days postinjury, a significant decrease of TPC was observed at the 5 mm rostral and 5 mm caudal sites compared to normothermic animals.


CONCLUSIONS
These results indicate that systemic hypothermia has a neuroprotective effect following SCI by attenuating post-traumatic TPC.
Shibuya
S
S
Department of Orthopaedic Surgery, Kagawa Medical University, Miki-cho, Kagawa, Japan.
Miyamoto
O
O
Janjua
N A
NA
Itano
T
T
Mori
S
S
Norimatsu
H
H
D000818:Animals; D007036:Hypothermia, Induced / Q000379:methods*; D020287:In Situ Nick-End Labeling / Q000379:methods*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013119:Spinal Cord Injuries / Q000473:pathology* / Q000628:therapy*