| Stroke is a focal (or at times global)neurological impairment of sudden onset,and lasting more than 24 hours (or leading to death)and of presumed vascular origin. It is a kind of cerebral vascular diseases including cerebral hemorrhage, ischemia and global cerebral ischemia and hypoxia.With the continuously prolonging of average lifespan, ischemic stroke has been become one kind of common and frequently-occurring disease to the old people because of its high incident. It is quite harmful to human beings because of the high incidence, high disability and high mortality of this disease. In china,ischemic stroke accounts for 55-80% stroke and continuously ascends resulted from increasing of the elderly. In order to further study and elucidate the pathophysiological mechanisms of ischemic stroke, and try to find a practical and efficient therapeutic method, a great deal of investigation has been conducted in the past few decades. However, the therapy of ischemic stroke is still a big difficulty although a variety of anti cerebral -ischemic drugs have been used in clinic. In the clinical practice of preventing cerebral ischemic disease, we have a profound knowledge of mechanisms on Chinese herbs preventing ischemic stroke . In Traditional Chinese Medicine, the basal mechanisms of ischemic stroke are deficiency in the basis and excessiveness in the exterior. The cause are that heart,liver, spleen and kidney are out of coordinate, deficiency, phlegm, heat and stasis affect each other. Therefore, the principle of treating ischemic stroke is to cure basis and exterior. tonify kidney, activate blood circulation and resolve phlegm. The traditional Chinese medicine is a big treasury. Much research about effects of traditional Chinese medicine on prevention and cure of ischemic stroke is progressively conducted. Significative achievements are gained no matter decoction or monomer and effective part extracted from a single Chinese herb.GB as a medicine that mainly cures stroke is a monomer extracted from ginkgo leaves by Chinese Peoples Liberation Army General Hocpital N.O.301.Based on pilot study,it is proved to have an effective action on anti-cerebral ischemia, reducing permeability of BBB and protecting cerebromicrovessel endothelial cells. The present study was designed to further clarify the brain protective effects and mechanisms of actions of GB by using different experimental methods (such as physiology, biochemistry, cell culture etc). The main results are as follows. (1) The effect of GB on vacuity of qi and stasis of blood model. GB(4mg/kg,8mg/kg,16mg/kg)could prolong the time of mouse swimming in the 8℃ cold water, and also can extend the time of breathing after head cutting off (P<0.05,P<0.01,compared with the model). The energy metabolism of the brain was abnormal after swimming in the 8℃ c old water, GB (8mg/kg,16mg/kg) could protect the brain by restraining the lactate producing, increasing the activation of LD,Na+-K+ATPase and Ca2+-Mg2+ATPase (P<0.05, P<0.01,compared with the model). (2) The effect of GB on blood brain barrier(BBB)permeability of common carotid artery occlusion(CCAO)rats. The permeability of BBB could be raised after CCAO.GB (2mg/kg,4mg/kg,8mg/kg) could significantly reduce the permeability for Evance Blue(EB) (P<0.05,P<0.01,compared with the model) ,so it could protect the BBB. (3) The protective effect of GB on cerebral ischemia reperfusion injury model of cerebralmicrovessel endothelial cell caused by hypoxia/reoxygenation in vitro. GB(10-3,10-4,10(-5)mol/L) attenuated the damage during hypoxia 3 h/reoxygenation (1,3,6,12,24,36,48,72h)which was reflected by the decrease of cells viability(quantified by MTT),and the increase of cell death(quantified by trypan blue). After hypoxia3 h/reoxygenation (1,3,6,12,24,36,48,72h),the activity of SOD and the activity of Na+-K+ATPase decrease and the content of NO increases in cell. GB104-mol/L could reduce the increasing of NO content. GB105-,10-6mol/L could enhance the decreasing of SOD activity... |
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