Effect of aminophylline on postischemic edema and brain damage in cats.

We attempted to ameliorate postischemic edema and brain tissue injury in cats by administering aminophylline to reduce the reactive hyperemia that supposedly aggravates both these sequelae. Forty-one cats were subjected to 1 hour of middle cerebral artery occlusion and were killed after 3 hours, 3 days, or 14 days of recirculation; one half of the cats received 0.916 ml/kg of a 25 mg/ml solution of aminophylline by infusion at a constant rate via the femoral vein starting 10 minutes before release of the occlusion and continuing for 5 minutes after initiation of recirculation; the other half received saline. Regional cerebral blood flow was monitored by the hydrogen clearance method and water content was evaluated by specific gravity measurements after 3 hours of recirculation; the status of the blood-brain barrier was assessed with Evans blue tracer. Morphologic observations were carried out in cats killed after 3 or 14 days of recirculation. Aminophylline-treated cats killed after 3 hours of recirculation showed significantly reduced hyperemia and edema and no leakage of Evans blue, which was present in all untreated cats killed after 3 hours or 3 days of recirculation. Morphologic observations revealed conspicuously more severe ischemic brain tissue damage in the untreated than in the aminophylline-treated cats after 3 and 14 days of recirculation. Our studies indicate the beneficial effect of administration of aminophylline in the amelioration of postischemic edema and brain tissue injury, which is presumably achieved by reduction of reactive hyperemia.