Changes in regional energy metabolism after closed head injury in the rat

We examined in the present investigation regional ATP, glucose, and lactate content in the cortical and subcortical structures, in a rat model of closed head injury (CHI). In serial tissue sections bioluminescence imaging of ATP, glucose, and lactate was performed at 4 h, 12 h and 24 h (n=4/5 per time point with) after the induction of CHI or sham surgery. Bioluminescence images were analyzed by computer-assisted densitometry, at the lesion site, in remote cortical areas, and in the subcortical structures (thalamus and caudate nucleus). ATP content was significantly decreased at the lesion site after 4 h and in the remote cortex at 12 h post-injury. At 12 h, the ATP content reached baseline levels on the ipsilateral side and at 24 h also at remote lateral parietal sites. In the contralateral cortex, ATP increased transiently above the baseline at 12 h. No significant changes in ATP were found in the thalamus and caudate nucleus. Cortical glucose and lactate contents could not be discerned over time. Following CHI there is an acute and progressive, yet transient, ischemic cortical profile, which is not reflected in subcortical areas.