| Objective:To study the dynamic changes of AQP4 expresion and the blood brain barrier in cerebral ischemia reperfussion in rats and the influence of the Radix Salviae Miltiorrzhizae and Ligustrazin.Methods:35 healthy Sprague-Dawley male rats were randomly allocated into 7 groups, sham-operation group (n=5)and operation group(n=20)which divided into 4 groups according to different time after cerebral ischemia reperfusion (6h,24h,48h,72h).Then on the time of the highest expression of AQP4 and the most damage of the blood brain barrier set up 2 groups (n=10) which one was drug group and another was saline group.The trsient focal ischemia reperfusion injury was induced by introducing a silicone-coated monofilament nylon suture from the right external carotid artery to the origin of the middle cerebral artery.The filament was removed after 2 hours to alow reperfusion.All the rats were tested for Longa neurological behavior,then killed by decapitation and the brains were taken out at each selected time. The permeability of blood brain barrier was measured by the amount of EB in the brain, and we observed the expression of AQP4 by immunohistochemistry staining.Results:①The neurological deficit symptoms appeared significantly after the rats suffered from the brain ischemia reperfusion injury.It showed an aggravated trend during the 6h-48h after reperfusion.However,the neurological symptoms started to alleviate at 72h.②At 24h after reperfusion the EB exudation was significant (P<0.05).The peak of EB exudation appeared at 48h after injury,and then EB exudation started to decrease.③The dynamical expression of AQP4 also increased significantly at 6h after ischemia reperfusion.At 48h after reperfusion it reached the summit. Then it remained such trend until 72h.Compared 48h with 72h, there was no significant difference.④There was significantly positive correlation between AQP4 expression and BBB permeability after the brain ischemia reperfusion injury in rats(r=0.87,P<0.01).⑤After gave the injection of Radix Salviae Miltiorrzhizae and Ligustrazin at 48h after reperfusion when the blood brain barrier was the most damaged,the AQP4 expresion and EB were significantly decreased compared with the saline group.Conclusion:①The upgrated AOP4 expression correlated tightly with the increased BBB permeability.and both are involved in the formation of edema induced by cerebral ischemia reperfusion in rats.②the Injection of Radix Salviae Miltiorrzhizae and Ligustrazin can improve neurological function deficits.The mechanical maybe by reduce brain edema through inhibiting of AQP4 expression to decrease the permeability of BBB. |
