The Study Of Protective Effect Of β-Aescinate Against Focal Cerebral Ischemia-reperfusion Injury In Rats

Cerebral infarction is a common disease leading to neuronal injury and has been the third lethal disorder.Once happened, it will seriously influence the survival quality of patients.A lot of studies have been started to investigate the mechanisims of cerebral ischemic injury. The effects of many therapies including traditional Chinese medicine and western medicine are unsatisfying.The ischemic torlerance induced by ischemic or drug preconditioning has been a hot spot in recent ten years, which provides a new method for cerebral protection. β -Aescinate can improve microcirculation around infarct area by its strong effects in anti-bleeding, clearing out oxygen free radicals, alleviating the injuries of vascular endothelial cells and other histiocytic cells, and its protective role was favored in cardiovascular system. In this experiment the protective effect of β -Aescinate was investigated in focal cerebral ischemia/reperfusion(I/R) model in rats, which provided scientific foundation for its applying to clinic.Experiment 1Objective: To investigate the protective effect of β-Aescinate against focal cerebral I/R injury in rats. Methods: Forty male SD rats were randomly divided into four groups(?10 in each group): Control group, β-Ae-5, β-Ae-10 and β-Ae-20 protective groups. In protective groups, β -Aescinate was injected into abdominal cavity indoses of 5, 10 or 20mg/kg respectively 30min before cerebral ischemia.The control group was injected with an equal volume of saline. After 120 min middle cerebral artery occlusion (MCAO) with 3-0 nylon suture via the right internal carotid artery, the suture was removed and the brain was reperfused.The neurologic outcome was evaluated until 24h after reperfusion. The brain infarct volume was then determined by TTC staining. Results: In control group the neurologic dysfunction was gradually aggravated. The neurologic deficit scores (NDS) in each protective groups at 24h after reperfusion were significantly lower than those of control group (P<0.05). The infarct volumes of protective groups were (87.921.3)mm3, (68.2 15.2)mm3 and (63.8 18.3)mm3 respectively,also significantly smaller than that of control group(P<0.05). Conclusion: The protective effect of β -Aescinate against focal cerebral I/R injury in rats was not dose-dependent.Experiment 2Objective: To investigate the relation between NO and cerebral ischemic injuries and the influence of β -Aescinate on the relations. Methods: In the MCAO model, we detected the contents of NO and MDA in brain tissue and the activity changes of NOS and SOD during I/R.We also observed the influence of β -Aescinate on the activity changes of NOS and SOD. Results: After MCAO, the contents of NO and MDA increased, the activity of NOS became higher and that of SOD got lower. However, β -Aescinate reversed the changes described above. Conclusion: The high level of oxidizing response leading to high contents of NO in early stage was a main cause of cerebral ischemic injury, while β -Aescinate may play a protective role by influence the level of NO in brain in early stage.Experiment 3Objective: To investigate the changes of cox-2 and neuronal apoptosis after cerebral I/R injury and to observe the effect of 3 -Aescinate on them. Methods: In the MCAO model, the evolvement of cell structure was observed by HE staining.The cox-2 expression was measured by immunohistochemistry method.The neuronal apoptosis was tested by TUNEL's. Results: In microscopic examination, either cellular swelling or death in 3 -Aescinate protected group was alleviated significantly and the expression of cox-2 protein decreased, which coincided with neuronal apoptosis. Conclusion: Cox-2 could induce neuron apoptosis after ischemia and enlarge the infarct area, while 3 -Aescinate might play a protective role.Experiment 4Objective: To investigate the changes of CGRP and ET-1 in brain after I/R injury and to observe the effect of 3 -Aescinate on them. Methods: In the MCAO model, The effect of 3 -Aescinate on CGRP and ET-1 in...