Effect of a prostacyclin derivative (OP-41483) and a hyperosmotic agent (glycerol) on brain edema and metabolism in cerebral ischemia.

A PGI2 derivative, OP-41483, and a hyperosmotic agent, glycerol, were tested for possible beneficial effects on brain edema, metabolism and pathological changes in cerebral ischemia. Combination treatment with these agents was also tested. Cerebral ischemia was produced in spontaneously hypertensive rats, using bilateral common carotid artery ligation (BLCL). OP-41483 was administered four times, hourly (500 ng/kg x 4, i.p.). Ten percent glycerol was administered intravenously (6.6 ml/kg). And, for the combination treatment, OP-41483 was administered three times, hourly (500 ng/kg x 3, i.p.), and 10% glycerol was administered intravenously (6.6 ml/kg) in the same manner as the glycerol treated group. In ischemic controls, saline was administered intravenously (6.6 ml/kg). After 3 h of ischemia, brain water content and metabolites were determined and pathological observation was conducted using electron microscopy. OP-41483 treated animals maintained higher levels of ATP concentration and reduced accumulation of lactate, but showed no difference in brain water content compared to saline treated controls. Glycerol treated animals showed significance in terms of reduction of brain water content and accumulation of lactate. Glycerol abated the depletion of ATP concentration. OP-41483+glycerol treated animals showed the most significant effect on the reduction of brain water content and accumulation of lactate. The combination treatment also maintained higher levels of ATP concentration. Additionally, swelling of astrocytic foot processes and mitochondria with destroyed crista were not observed pathologically in the combination treated animals. These results show that OP-41483, glycerol and combination treatment are beneficial in the treatment of cerebral ischemia. They also indicate that the combination treatment significantly enhances the protective effects compared to individual treatment.