Comparison In Two Methods Of Making PMCAO And The Effect Of Catalpol

Stroke is a widespread disease affecting human health, especially Ischemic Cerebrovascular Disease, ICVD, accounted for about85%. Ischemic cause kinds of neurological dysfunction, and seriously affect the quality of life in patients with heavy economic and psychological burden to patients’ family and all society.Therefore, searching for new drugs for prevention and treatment of ischemic disease is becoming a concerning point in current pharmaceutical academic researches. Making model of ischemia in animal provides a powerful means for drugs screening. Simulating the characteristics of cerebral ischemia, making cerebral ischemia in animal, and studing the variation of ischemia pathology and pathogenesis are of great significance in looking for therapeutic targets of stroke.Objectives:In order to identify the characteristics of the two methods and to provide experimental evidence for correct choice of ischemia models in animal pathological pathophysiological mechanisms and new drug development, we study that comparison of two methods in making ischemia in animal and the effect of Catalpol.Part I:The comparative study on two methods of making the permanent middle cerebral artery occlusionMethods:Study chose two methods of making Permanent Middle Cerebral Artery Occlusion (pMCAO). One is induced by permanent focal cerebral ischemia via surgical insertion of a nylon filament into the internal carotid artery. Another is induced by the electrocoagulation on the middle cerebral artery. Then we observed feature in making stroke with two method after neurological behavior score (Neuromuscular function score, Hanging Wire test, Bederson score, Beam walking test) and TTC staining detection.Results:Ischemia was induced by permanent focal cerebral ischemia via surgical insertion of a nylon filament into the internal carotid artery. Infarct size expanded with the time going. Infarct size was up to25.6%和44.9%24h and48h after brain injuried. Infarct size was the most serious condition in our experiment, reaching45.7%72h after injuried. Mortality rate was up to28.57%. Neuromuscular function score and Hanging Wire test was used in our study. The longer the time, the more severe of the injury. But there was no significant difference between each group in neurological behavior score (P<0.05).Ischemia was induced by electrocoagulation of the middle cerebral artery. Infarct size was the most serious condition in our experiment, reaching25.05%72h after brain injuried. Mortality rate was zero. There was no significant difference between each group in neurological behavior score. Infarct size was depend on the location of the middle cerebral artery by electrocoagulation, such as cortex, subcortex. The method of making ischemia which induced by electrocoagulation of the middle cerebral artery has a high success rate and low mortality rate. Infarct size expanded with the time going on. Infarct size of brain is2.61%、7.76%、19.26、20.16%和25.05%in brain after6h,12h,24h,48h and72h stroke. The mortality rate was zero. In the study, we choose three methods to evaluate animal neurologic deficit evaluation:Bederson score, Hanging Wire test, Beam walking test. There was no significant difference in each group for neurologic deficit evaluation.Part Ⅱ:Effect of Catalpol on pMCAO making by two methodsMethods:Study used two methods of making animal Permanent Middle Cerebral Artery Occlusion. Then animal treated with Catalpol, we observed pathological changes after pMCAO by neurological behavior score (Neuromuscular function score, Hanging Wire test, Bederson score, Beam walking test) and TTC staining detection. The study aims to indicate the effect of Catalpol in two aspects:(l)therapeutic time-window (2)dose-effect. Western Blot analysis of the expression of VEGF、 STAT3and p-STAT3in cortex and the effect of Catalpol.Results:Short-term study results showed that Catalpol with doses at7mg/kg and14.2mg/kg reduced infarct size significantly, but there was no significant difference in neurologic deficit. The results of neurologic deficit evaluation was different from infarct size analysis. Therapeutic time-window of protection of Catalpol was investigated by changing its first administration (0.5h before stroke, lh,24h after stroke) after surgery. Although reduced the infarct size which the first administration was24h after stroke, it was better to choose the first administration in0.5h before and1h after stroke. There was no significant difference in each group for neurologic deficit evaluation.Long-term study results showed that Catalpol significantly attenuated neurologic deficit and reduced infarct size induced by pMCAO. The highest dose (lOmg/kg) not only reduced Bederson score and beam-walking score, but also increased muscle strength after7and15d stroke. The results of neurologic deficit evaluation showed that differences exist between the model group and the Catalpol group. Therefore, Catalpol have a function of repairation on neurologic deficit. There methods of neurologic deficit evaluation on Bederson score, Hanging Wire and Beam-walking score could evaluate neurologic deficit and show the protection effect of Catalpol.Study showed the level of the protein expression after ischemia in different point. Results showed that the expression of protein was increased with the time going by. Stroke reduce the expression of protein after15d. Catalpol significantly increased the level of the protein after15d ischemia, the same as21d.Conclusion:(1) Ischemia which induced by permanent focal cerebral ischemia via surgical insertion of a nylon filament into the internal carotid artery was injuried seriously and have a high mortality rate. It suit to treat acute ischemia injury.(2) The mortality rate of ischemia induced by the electrocoagulation on the middle cerebral artery was low extremely. The infarct size of ischemia was able to control effectively. It was beneficial to select ischemia drug effectively, and it suit for the study of nerve repairment(3) TTC assay reflected the infarct area with the time going by. In the study, we choose three methods to evaluate animal neurologic deficit evaluation:Bederson score, Hanging Wire test, Beam walking test. There was no significant difference in each group for neurologic deficit evaluation.(4) Catalpol could reduce infarct size with dose dependent. It could reduced the infarct size which the first administration were0.5h before and1h after stroke. (5) It was related to JAK2/STAT3/VEGF signal protein in stroke treatment with Catalpol.