【作者】 张云平；

【导师】 吴仁华；

【作者基本信息】 汕头大学 ， 病理学与病理生理学， 2008， 博士

【摘要】 缺血缺氧脑病是世界范围的第二大致死因素,椐统计每年死于中风的人群占总死亡人数的9.5%,达到五百万。如此高流行、高病死率给整中国乃至世界带来沉重的病痛及经济负担。但脑缺氧缺血具有极其复杂的病理生理过程,急性缺氧缺血可造成脑损伤,并导致脑能量代谢的改变。因此探索此类疾病的发病机理及寻找治疗方法及预防的手段极为必要。本课题旨在揭示超急性期/急性期脑缺氧缺血过程中乳酸及其他主要脑代谢物随时间的变化规律。研究结果有助于了解超急性期/急性期脑缺氧缺血的损伤机理和发病机制,还有助于探索准确、有效、方便的测定脑代谢物的方法。在本研究中,作者以小鼠缺氧缺血性脑损伤模型为研究对象,使用乳酸试剂盒、HPLC和高场磁共振频谱三种不同方法,以秒为单位分别观察了急性缺血缺氧小鼠大脑的乳酸、磷酸肌酸、乙酰-门冬氨酸四种代谢物随时间的变化过程,改进了脑代谢物的HPLC的检验方法,并比较了三种方法的相关性,为进一步准确稳定的检测大脑代谢物奠定了基础。本实验结果揭示了乳酸、磷酸肌酸N-乙酰门冬氨酸和胆碱在急性脑缺血缺氧中随时间的变化规律:乳酸在缺血发生20秒钟时即升至到最高4.16μmol/g(wet)并随缺血缺氧的时间的延长而上升;磷酸肌酸浓度水平在缺血缺氧20秒钟时就大幅降低至6.17±0.39μmol/g(wet),5分钟时最低;N-乙酰门冬氨酸的变化趋势是在缺血缺氧的早期5分钟开始下降9.43±0.18μmol/g(wet),10分钟降低到最低8.32±0.29μmol/g(wet);胆碱的变化则无显著性差异(P>0.05),与一些文献报道不符。三种方法的相关性为:乳酸试剂盒与HPLC测定乳酸的相关系数为0.814;9.4T磁共振频谱与HPLC的相关系数为0.900。总之,乳酸、N-乙酰门冬氨酸和磷酸肌酸是急性缺血缺氧的敏感指标,而胆碱的变化则无显著性差异(P>0.05)。通过三种检测乳酸方法的相关性比较,说明高场9.4 1H-MRS是测定离体生物样本乳酸浓度更为可靠的方法。更多还原

【Abstract】 Hypoxic-ischemic encephalopathia is the second leading cause of mortality worldwide. It is estimated to be responsible for 9.5% of all deaths and 5.1 million of the 16.7million cardiovascular disease deaths. In China, hypoxic-ischemic encephalopathia is the leading cause of mortality and it is threating life of people worldwide. Hypoxic-ischemic encephalopathia, however, is most complicated process and its procedure occurs in brain will result in multineurodisfunction, including: failure of energy metabolitic produce, changes in multiactive compound in brain and serious sequelae. So it is necessary to reveal the pathological mechanism of hypoxic-ischemic encephalopathia and find effective approach for prevention and treatment.At present study we induced rat model to mimic the procedure of hyperacute hypoxic-ischemi encephalopathia to study the time courses of multimetabolic(Choline, NAA, P-Cr, Lac)dynamic changes in rat brains model of hyperacute global cerebral ischemia within 20 min.A total of 80 rats were randomized into five different groups, the normal (n=5), the hyperacute global cerebral ischemic groups (n=5). A rat model of acute global cerebral ischemia was induced by cutting the rat heads. The lactate concertrations were measured by lactate kit, the four brain metabolitics were measured by HPLC and 9.4T 1HMRS.In the normal group and the ischemic group, the time course of metabolites were revealed, significant differences in Lac, NAA and P-Cr concentration were found between two groups(P<0.05). The marked increase in Lac, and declined in P-Cr and NAA (P<0.05). However, Choline concentration was not significant change in all groups within 20 min after cerebral ischemia period(P>0.05). The earliest detection of lactate was at 20 seconds within the ischemic period, the lactate concentration elevated and peaked at 20s and declined with development of ischemia at 5min reached the ebb, after the ebb lactate began to rise. Methods were compaired between Lac kit and HPLC, the coefficient of correlation is r=0.814; and the methods between HPLC and 1H-MRS, the coefficient of correlation is r=0.900.In conclusion, the time courses of multimetabolites in ischemic rat brains were depict in early stage: abnormalities in acute stage of cerebral ischemia in rats could also be detected by 1H-MRS and another two methods. The study shows that 1H-MRS is a reliable and gave important information for evaluating hypoxic and ischemic pathologic procedure.更多还原