Ischemic brain damage induced by repeated brief occlusions of bilateral common carotid artery in rats

Two temporary occlusions of the bilateral common carotid artery for 15 min with an interval of 15 min induced severe brain tissue damage in normotensive Wistar rats. Although no lesions were seen after a single 15-min occlusion, severe ischemic lesions were found in 68% (49/72) of the rats injected to two consecutive occlusions for 15 min with an interval of 15 min, and the incidence was significantly higher than that in the rats subjected to a single 30-min occlusion (32%, 6/19) or two 15-min occlusions with an interval of 30 min (11%, 1/9). The local cerebral blood flow (lCBF) in the caudoputamen, however, was decreased by only 40-60% of pre-occlusion level during occlusions. These results suggest that intermittent incomplete disruption of CBF with short intervals could be more hazardous than a continuous interruption of the same duration.