Changes in cortical and subcortical energy metabolism after repetitive and single controlled cortical impact injury in the mouse.

In the present investigation we examined regional ATP, glucose, and lactate content in the cortical and subcortical region, in a mouse model of controlled cortcal impact (CCI) injury. In serial tissue sections, bioluminescence imaging of ATP, glucose, and lactate was performed 1 h after a single CCI injury or sham surgery and 15 min, 1, 24, and 48 h after the induction of a second CCI injury 24 h later or sham surgery. Bioluminescence images were analyzed by computer-assisted densitometry at the lesion site, at the contralateral site, and in a subcortical region. After repetitive CCI injury, the cortical ATP content decreased bilaterally at 15 min and 1 h, and reached a significant minimum at 24 h, as compared with sham. At 48 h the ATP content bilaterally reached base level again. No significant changes in ATP were found in the subcortical region. After repetitive CCI injury, the lactate content increased bilaterally, reached a significant level at 15 min at the trauma site, and bilaterally reached a significant maximum at 1 h. Thereafter, lactate content decreased below base level without reaching significance and reached baseline again at 48 h. In the ipsilateral subcortical region, lactate content increased transiently above the baseline at 1 h and decreased to a significant minimum at 24 and 48 h. No significant changes were found in the contralateral subcortical area. No significant differences between glucose content in sham animals and the cortical and subcortical area could be measured over time; the subcortical glucose content was bilaterally lower than cortical content at all time points and reached a significant minimum bilaterally at 48 h after repetitive CCI injury compared with cortical glucose content. Single CCI injury did not affect ATP, glucose, and lactate contents at any time point. Repetitive CCI injury caused a more severe depression in cerebral metabolism at early time points after trauma compared with a single CCI injury and indicates that lactate might be an early indicator of post-traumatic metabolic disruption.