Temporary cerebral ischemia. Effects of pentastarch or albumin on reperfusion injury.

Recent investigations have proposed that, after temporary ischemia, pentastarch may reduce microvascular permeability and reperfusion injury. However, this hypothesis has not been tested in the brain. Accordingly, after 180 min of temporary middle cerebral artery occlusion, the effect of pentastarch or albumin on blood-brain barrier permeability and cerebral injury was investigated in isoflurane-anesthetized rats. One of the following was maintained for the final 60 min of occlusion and throughout reperfusion: control-hematocrit was not manipulated; pentastarch-hematocrit was decreased to approximately 30% with pentastarch; or albumin-hematocrit was decreased (approximately 30%) with albumin. Part A (n = 21): 30 min of reperfusion was allowed, and blood-brain barrier permeability was determined with the indicator dye Evans Blue. Part B (n = 14): in different animals, 120 min of reperfusion was allowed, and cerebral injury (2,3,5-triphenyltetrazolium chloride stain) and edema (specific gravity) were assessed. Part C (n = 4): in different animals, the blood-brain barrier was evaluated by electron microscopy. Evans Blue (micrograms per gram brain tissue, mean +/- SD) was greater in the control (20.8 +/- 9.0) and albumin (15.5 +/- 7.3) groups versus the pentastarch (4.7 +/- 2.7) group (P less than 0.05). Brain injury (percent of hemisphere ipsilateral to occlusion) was less and specific gravity greater in the pentastarch (33 +/- 8 and 1.040 +/- 0.003 respectively) versus the albumin group (45 +/- 6 and 1.035 +/- 0.003). This study supports the hypothesis that during temporary cerebral ischemia, pentastarch decreases brain injury and edema.(ABSTRACT TRUNCATED AT 250 WORDS)