Experimental Studies On Improvement Of Cerebral Ischemia And Reperfusion Injury By Bajisu

Objective:The cerebrovascular disease, which has these characteristics of higher morbidity, higher disability, higher mortality and higher relapse rate, has become the primary cause of death and disability in the elderly. The incidence of the ischemic stroke is about 59. 8% of the rate of stroke. It is significant to study the ischemic stroke. When it is in cerebral ischemia-reperfusion, lots of inwards-flow ways of calcium lead to Ca²⁺ overload , which can cause a series of pathologic reactions, activate cell death gene transcription at last and induce serious cerebral injury , such as the programmed cell death . Ca²⁺ overload is "the last common way" of neural cell death. The opening of the L-type calcium channel will be useful to influx pathways of Ca²⁺ and rise the intracellular Ca²⁺ concentration. The cerebral ischemia pertains to the stroke in Traditional Chinese Medicine (TCM) and the therapy of TCM is centuries old, which has accumulated abundant experiences. The research, which apply the modern technology and from the general level and cell-and-molecule level respectively, study the cerebral protective function of acute cerebral ischemia in mice and the intracellular Ca²⁺ concentration and L-type calcium channel in CA1 pyramidal neurons of rat hippocampus in cerebral ischemia-reperfusion rats by bajisu extracted from Chinese herb named Morinda officinalis How, which provide experimental evidence for exploitation of medicines protecting cerebral neuronal.MethodsThe general level experiment was applied acute cerebral ischemia or anoxia experimental method. Twenty-seven weighting from 21g to 24g KM mice was divided into three groups at random ,0.9%NaCl solution control group, bajisu low dose(100mg/kg) group and bajisu high dose (200mg/kg) group . Each group was have given injecta by intraperitoneum injection five days, one time a day . One hour after last intraperitoneum injection, every mouse was given quick decapitation and record the gasping time after quick decapitation. Use gasping time and times of breath as indexes to observe protective effects of bajisu on acute cerebral ischemia or anoxia.Cell-and-molecule level experiment consulted the modified Pulsinelli' s tetra-vessel occlusion to prepare the global cerebral ischemia rats. The experiment was divided into 10 groups: the sham-operated group, ischemia group, reperfusion at time points(30min, 2h, 6h)groups and bajisu groups(including 5 groups, each group was each group above after being given bajisu). On the basis of the global cerebral ischemia and reperfusion models, Each group CAl pyramidal neurons of rat hippocampus was acquired in the acute separation method, then, record and analyze the intracellular Ca²⁺ concentration in nine cells by TillVision. Single L-type calcium channel current of six cells was recorded in cell-attached patches collected into the computer by Pulse & PulseFit and the current average open time was analyzed by TAC&TACFit .Result:1. At the general level , experimental groups compared with 0.9%NaCl solution control group , bajisu low dose group and bajisu high dose group could all significantly prolong the gasping time of mice and increase times of breath after quick decapitation (P<0.05 and P<0.01 respectively) .There is an up-tendency of gasping time and times of breath between bajisu low dose group and bajisu high dose group, but no significant difference.2. Changes of the Ca2+ concentration in the CAl pyramidal neurons of rat hippocampus and the effects of bajisu with global cerebral ischemia and reperfusion at different time points: At 30min and 6h after ischemia and reperfusion, the Ca2+ concentration was significantly increasing when compared with sham-operated group. The Ca2+ concentration of ischemia group and reperfusion at 2h group was increasing, but they had no significant difference with sham-operated group . It was found that bajisu have obviously dropped the...