THE BIPHASIC OPENING OF THE BLOOD-BRAIN-BARRIER IN THE CORTEX AND HIPPOCAMPUS AFTER TRAUMATIC BRAIN INJURY IN RATS

This study examined the time course of the blood-brain barrier (BBB) o pening and correlated this with brain edema formation after a lateral controlled cortical impact (CCI) brain injury in rats. Quantitative me asurement of Evans blue (EB) extravasation using fluorescence was empl oyed at 2, 4, 6 h and 1, 2, 3, 4 and 7 days after injury. Brain edema was measured by specific gravity of the tissue at corresponding time p oints. Two prominent EB extravasations were observed at 4-6 h and 3-da y after injury in the injury-site cortex and the ipsilateral hippocamp us. Brain edema became progressively more severe over time and peaked at 24 h after injury and began to decline after day 3. These results s uggest that there is a biphasic opening of the BBB after CCI brain inj ury and the second opening of the BBB does not contribute to a further increase in edema formation. (C) 1997 Elsevier Science Ireland Ltd.