Although systemic cooling had recently been reported as effective in improving the neurological outcome after
traumatic brain injury, several problems are associated with whole-body cooling. The present study was conducted to test the effectiveness of brain cooling without interference with the core temperature in rats after fluid percussion
traumatic brain injury (TBI). Brain
dialysates ischemia (e.g.,
glutamate and
lactate-to-
pyruvate ratio) and injury (e.g.,
glycerol) markers before and after TBI were measured in rats with mild brain cooling (33 degrees C) and in the
sham control group. Brain cooling was accomplished by infusion of 5 mL cold saline via the external jugular vein under
general anesthesia. The
weight loss was determined by the difference between the first and third day of
body weight after TBI. The maximum grip angle in an inclined plane was measured to determine motor performance, whereas the percentage of maximal possible effect was used to measure blockade of proprioception. The
triphenyltetrazolium chloride staining procedures were used for
cerebral infarction assay. As compared with those of the
sham-operated controls, the animals with TBI had higher values of extracellular levels of
glutamate,
lactate-to-
pyruvate ratio, and
glycerol in brain and intracranial pressure, but lower values of cerebral perfusion pressure. Brain cooling adopted immediately after TBI significantly attenuated the TBI-induced increased
cerebral ischemia and injury markers,
intracranial hypertension, and cerebral hypoperfusion. In addition, the TBI-induced
cerebral infarction, motor and proprioception deficits, and
body weight loss evaluated 3 days after TBI were significantly attenuated by brain cooling. We successfully demonstrate that brain cooling causes attenuation of TBI in rats by reducing
cerebral ischemia and injury resulting from
intracranial hypertension and cerebral hypoperfusion. Because jugular venipuncture is an easy procedure frequently used in the emergency department, for preservation of brain function, jugular infusion of cold saline may be useful in
resuscitation for
trauma patients.