Effect of mild hypothermia on brain dialysate lactate after fluid percussion brain injury in rodents.
OBJECTIVE
To investigate the effects of mild hypothermia on brain microdialysate lactate after fluid percussion traumatic brain injury (TBI) in rats.


METHODS
Brain dialysate lactate before and after fluid percussion brain injury (2.1 +/- 0.2 atm) was measured in rats with preinjury mild hypothermia (32 degrees C), postinjury mild hypothermia (32 degrees C), injury normothermia (37 degrees C), and the sham control group. Mild hypothermia (32 degrees C) was induced by partial immersion in a water bath (0 degrees C) under general anesthesia and maintained for 2 hours.


RESULTS
In the normothermia TBI group, brain extracellular fluid lactate increased from 0.311 +/- 0.03 to 1.275 +/- 0.08 mmol/L within 30 minutes after TBI (P < 0.01) and remained at a high level (0.546 +/- 0.05 mmol/L) (P < 0.01) at 2 hours after injury. In the postinjury mild hypothermic group, brain extracellular fluid lactate increased from 0.303 +/- 0.03 to 0.875 +/- 0.05 mmol/L at 15 minutes after TBI (P < 0.01) and then gradually decreased to 0.316 +/- 0.04 mmol/L at 2 hours after TBI (P > 0.05). In the preinjury mild hypothermic group, brain extracellular fluid lactate remained at normal levels after injury (P > 0.05).


CONCLUSIONS
The cerebral extracellular fluid lactate level increases significantly after fluid percussion brain injury. Preinjury mild hypothermia completely inhibits the cerebral lactate accumulation, and early postinjury mild hypothermia significantly blunts the increase of cerebral lactate level after fluid percussion injury.
Jiang
Ji-Yao
JY
Department of Neurosurgery, RenJi Hospital, Shanghai Second Medical University, Shanghai, People's Republic of China. jiangjyb@online.sh.cn
Liang
Yu-Ming
YM
Luo
Qi-Zhong
QZ
Zhu
Cheng
C
D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D001831:Body Temperature / Q000502:physiology; D020833:Diffuse Axonal Injury / Q000473:pathology / Q000503:physiopathology; D045604:Extracellular Fluid / Q000378:metabolism; D005625:Frontal Lobe / Q000473:pathology / Q000503:physiopathology; D016489:Head Injuries, Closed / Q000473:pathology / Q000503:physiopathology*; D007036:Hypothermia, Induced; D019344:Lactic Acid / Q000378:metabolism*; D008297:Male; D017551:Microdialysis; D051381:Rats; D017207:Rats, Sprague-Dawley
D019344:Lactic Acid