Experimental Studies Of The Protective Effects Of Puerarin On Focal Cerebral Ischemic Injury And Spinal Cord Ischemic Injury

Objective: To investigate the protective effects and mechanisms of Puerarin on focal cerebral ischemic injury and spinal cord ischemic injury , providing the theoretic base for Puerarin to treat the neuronal ischemic injury.Methods: 1. sixty male SD rats were randomly divided into two groups(thirty in each group) : control group and puerarin group. The animals in each group were randomly allocated into six subgroup(n=5) according to the time points at 6,12,18,24,48 and 72h reperfusion following 90min middle cerebral artery occlusion(MCAO). In puerarin group, puerarin 60mg/Kg were administered intraabdominally 10min before MCAO. In control group, 0.9% saline of the same volume was used as puerarin group. Right MCAO was induced in all animals by a 4-0 nylon thread with round tip inserted cranially into right internal carotid artery and maintained for 90 min. HSP70 mono-clone antibody immunocytochemistry was used to detect the changes of HSP70 expression in rat cortex at 6, 12,18,24,48 and 72h reperfusion in conjunction with histopathological analysis of rat brain. 2. Twenty male New Zealands white rabbits wererandomly divided into two groups: control group (n=10) and puerarin group (n=10) . Spinal cord ischemia was induced in all animals by occluding infrarenal abdominal aorta for 20min. In puerarin group, puerarin 30mg/kg was administered intravenously lOmin before aortic occlusion. In control group , 0.9% saline was used as puerarin group. The production of MDA -, the activities of SOD -, the levels of plasma TXB2 and 6-keto-PGFla were assayed before,during and after cross-clamping. Neurologic status was scored at 4,8,12,24,48 hours after reperfusion. All animals were killed 48h after reperfusion and the spinal cords were studied histopathologically. Results: 1. In control group, HSP70 expression could be observed at 6h reperfusion ,and it reached peak at 24h reperfusion. In puerarin group, the expression of HSP70 was elevated at 6,12,18,24 and 48h reperfusion compared with control group , and it reached peak at 18h reperfusion in advance. Under optical microscope , less degree of cerebral ischemic injury was seen in puerarin group at different time points after reperfusion compared to control group. 2. During and after cross-clamping ,the production of MDA in puerarin group was lower than those in control group (p <0.05), but the activities of SOD in puerarin group were higher than those in control group (p <0.05); At 20min ischemia and 18h reperfusion, compared with control group , the level of plasma TXB2 in puerarin group was lower, but at 20min ischemia, the level of plasma 6-keto-PGFla in puerarin group was higher. The Neurologic function scores at 4, 8, 12, 24, 48h after reperfusion were higher in puerarin group than those in control group (p <0.05); Compared to control group, less degree of injury was seen in puerarin group under optical microscope 48h after reperfusion.Conclusions: 1. puerarin could enhance the expression of HSP70 induced by focal cerebral ischemia , advance the peak of HSP70 expression and also alleviate cerebral ischemic changes histopathologically. 2. Puerarin could protect rabbit spinal cord ischemic injury . The protective mechanisms of puerarin are associated with the effect of strengthening antioxidation and improving the imbalance of TXA2-PGI2 following rabbit spinal cord ischemic injury.