The mechanism of 3-methoxy puerarin on decreasing the cerebral ischemia-reperfusion injury in rats

The aim of this study was to explore the mechanism of 3-methoxy puerarin on decreasing the cerebral ischemia-reperfusion injury in rats. Before the model of cerebral ischemia-reperfusion injury was made, the rats in one group (3-methoxy puerarin group, 3-MP group) were pretreated with 3-methoxy puerarin (100 mg/kg) by gavageing two times per day for seven days. At an hour before operation, the rats in the 3-MP group were additionally given 3-methoxy puerarin by gavageing once. The level of prostacyclin (PGI2) and the expression of endothelin-1 (ET-1) mRNA in cerebral tissue, the activity of plasma tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI) were measured. Cerebral tissue pathologic changes were also observed. The levels of PGI2 in cerebral tissue and the activity of plasma t-PA in 3-MP group were significantly higher than those in the group of cerebral ischemia-reperfusion injury (CIRI group) (p<0.01). The activity of plasma PAI and the expression of ET-1 mRNA in cerebral tissue in 3-MP group were significantly lower than those in CIRI group (p<0.01). The cerebral tissue pathologic changes were significant in CIRI group, which were significantly ameliorated in the 3-MP group. The study showed, in the rat model of cerebral ischemia-reperfusion injury, 3-methoxy puerarin can not only increase the level of PGI2 in cerebral tissue and the activity of plasma t-PA, but also inhibit the activity of plasma PAI and the expression of ET-1 mRNA in cerebral tissue. Those findings might be the mechanisms behind the protecting effects of 3-methoxy puerarin on the cerebral ischemia-reperfusion injury.