The Protective Effect Of Astragalus Injection Pretreatment On The Spinal Cord Ischemia-reperfusion Injury(IRI) In Rats

ObjectivePostoperative neurologic deficit due to spinal cord ischemia-reperfusion injury is the devastating complication following thoracoabdominal aortic aneurysm repairs. In Chinese Traditional Medicine documents, Astragalus is effective for neurologic deficit caused by spinal cord injury. In this study, We should try to explain Whether and How Astragalus injection pretreatment on the spinal cord ischemia-reperfusion injury(IRI) in rats has the protective effect.Methods SD rats were randomly divided into sham operation group(group A), ischemia reperfusion group(group B), Astragalus injection pretreatment group(group C). In the group C(Astragalus injection pretreatment group), Astraga Lus injection(6.41 m L/kg) was injected intraperitonea LLy 30 min prior to aortic clamping. Similar Ly, 0.9% saline was injected intraperitoneally in the group B. ALL experiment anima Ls were anesthetized with 1% sodium pentobarbital solution(40mg/kg) intraperitoneally and operated under sterile conditions. The group A subjected to operation without abdominal aortic occlusion. But in the group B and C, ischemia of the spinal cord was induced by occlusion over the right renal artery for 32 min. Neuro Logical outcome of all experiment animals was scored after reperfusion. At hour 2,8,12,24,48 following reperfusion, the vein blood of right ventricle was took out for measureed and the L2-4 segment spinal cord of mode Ls were collectd to observe the change of Ca2+, AQP4 and apoptosis cells.Results1. BBB scoring system evaluated the nerve function. Compared to group A, group B and group C showed a significant functional deficit(P<0.05).At each time point(2, 8,12,24,48h), the BBB scores of group B were Lower significantly than those in Group C(P<0.05).2. The concentrations of NSE in blood serum after ischemia reperfusion in Group B and C were higher significantly compared with those in Group A(P<0.01).But the concentrations in Group C were lower significantly than those in Group B(P<0.01).3. The concentrations of Ca2+ in L2-4 spinal cord in group A were decreased significantly than those in group B and group C. But the concentrations in Group B were increased significantly than those in Group C at each time point(P<0.01).4. Western blot analysis measured the express of AQP4 protein in each group. The AQP4 level of group B and C were higher significantly than those in group A. The expression of AQP4 in group B and C increased gradually, but the group B reached its peak at 12 h time piont and the group C at 24 h time piont. At each time piont, the expression of AQP4 in group C was markedly Lower than those in group B. 5、TUNEL staining could detect the apoptotic cell in spinal cord tissue after ischemia reperfusion. In our expriment, the apoptotic index of group A was Lowest in three groups. Compared with group C, the apoptotic index of group B was increased markedly.Conlusion: 1. Astragalus injection could decrease the expression of AQP4, Ca2+and the concentrations of NSE in blood serum induced by spinal ischemia reperfusion,defer the peak of expression of AQP4 and also alleviate spinal ischemic reperfusion injury changes histopathologically.2. Astragalus injection has protective effect in rats spinal cord ischemic reperfusion injury.The protective mechanisms of Astragalus injection are associated with the effect of reducing spinal cord oedema and alleviating the apoptosis following rats spinal cord ischemic reperfusion injury.