【作者】 徐涛；

【导师】 崔丽英；

【作者基本信息】 中国协和医科大学 ， 神经病学， 2007， 博士

【摘要】 背景和目的:缺血性脑血管病是临床常见病和多发病,致残率和病死率高。如何采取合理的措施预防和治疗脑梗死,恢复受损神经细胞功能,降低致残率和病死率,一直是医学界关注的热点问题。缺血性脑水肿是脑缺血后继发性损伤的一大因素,也是缺血性脑血管病患者急性期死亡的一个主要原因,如果能够采取有效的治疗措施及时抑制或减轻脑水肿的发生、发展,势必可以阻止损伤进一步加重,挽救受损的神经细胞。另一方面,如何采取有效手段激发或增强脑缺血后的神经重塑作用,促进神经功能的恢复,也逐渐成为神经科学者尤其是神经康复学者的兴趣所在。经颅重复频率磁刺激(rTMS)是将一定频率和强度的磁脉冲以成串刺激的方式以一定间隔连续发放。由于其独特的生物学效应,目前临床上用于对重症抑郁、运动障碍类疾病的治疗。但rTMS对于缺血性脑血管病的影响仍处于研究阶段。本实验旨在观察大鼠大脑中动脉缺血再灌注损伤后24h神经功能情况、脑含水量以及水通道蛋白4(AQP4)表达的变化,探讨rTMS对脑梗死后水肿的影响;同时观察损伤后7d时生长相关蛋白-43(GAP-43)、突触素(SYN)表达的变化,结合大鼠神经功能情况,探讨rTMS对梗死后可塑性的影响。方法:制作雄性SD大鼠右侧大脑中动脉栓塞(middle cerebral artery occlusion,MCAO)1.5h后再灌注模型,于再灌注即刻开始,给予不同频率和强度的rTMS,即5Hz、100%MT(低频低强);5Hz、200%MT(低频高强);20Hz、100%MT(高频低强);20Hz、200%MT(高频高强),同时设立假刺激组和假手术组进行对照。观察rTMS对大鼠脑缺血再灌注24h内神经功能缺损的影响以及脑组织的含水量、AQP4表达的变化;同时观察连续7d应用rTMS后脑组织GAP-43、SYN表达的变化及大鼠神经功能的变化。结果:发现脑缺血再灌注大鼠出现局灶性梗死灶、不同程度的脑水肿及神经功能障碍,24h内死亡率较高。rTMS可以使大鼠脑组织内的AQP4的表达下降,脑水肿减轻,降低24h内死亡率,20Hz、200%MT的rTMS(高频高强组)作用突出,各项指标与假刺激组比较均有统计学显著性差异(P＜0.05)。连续7d给予rTMS可以明显改善大鼠神经功能障碍的程度,上调脑组织GAP-43、SYN表达,20Hz、200%MT的rTMS(高频高强组)作用突出,各项指标与假刺激组比较均有统计学显著性差异(P＜0.05)。结论:不同频率和强度的rTMS对脑缺血再灌注损伤的大鼠具有神经保护和神经重塑的双重作用。rTMS可以降低脑缺血再灌注损伤后急性期死亡率,促进肢体恢复。rTMS可以减轻脑缺血再灌注损伤后大鼠的脑水肿,这一过程可能与减少AQP4蛋白的表达有关。连续rTMS可以促进脑缺血再灌注损伤后大鼠的神经功能的恢复。连续rTMS可以促进脑缺血再灌注损伤后大鼠脑组织内源性GAP-43和SYN的表达,发挥神经重塑作用。高频高强rTMS上述作用最显著。更多还原

【Abstract】 Background and purpose:The appropriate methods of prevention and therapy for cerebral ischemia to restore the function of damaged neurons as well as to reduce disability and mortality remain a subject of debate.The cerebral edema on acute stage after ischemia is both the main secondary lesions and the important causes of death. How to control the developing of ischemic edema represents the main target of acute stroke therapy.On the other hand,more and more neurologists confirmed that the plasticity of the brain had played an important role during the rehabilitation period and the treatment for enhancing the plasticity of the brain have been the attention focus for a long time.Repetitive transcranial magnetic stimulation(rTMS) which occurred in the last decade can affect the functional state of the local stimulus and remote sites.It has been a routine treatment alternative for the major depression or some dyskinesia diseases,but it is still on an investigation stage about whether rTMS could affect the pathophysiological conditions of ischemic stroke.So,one of the aim of this study is mainly to investigate the effect of rTMS on the ischemic cerebral edema and the expression of AQP4 at the acute stage of middle cerebral artery occlusion and reperfusion injury.Another aim is to investigate the possible effect of rTMS on the plasticity of the brain.Methods:Established the SD rat MCA cerebral ischemia-reperfusion model with suture occlusion technique according to modified Zea Longa method and then the rats were devide into four therapy groups.Different rTMS were applied to them right after the reperfusion was performed and once a day during the next 7 days followed.Sham-rTMS and sham-operating group were set as the control group.At 6h,12h and 24 h after the reperfusion,the neurological impairment evaluation score of a part of rats were recorded and then were killed to measure the water content of the brain and the protein AQP4 levels by immunohistochemistry and Western blot technology,the extent of neurological deficits graded as scores of other rats were evaluated every other day and then were killed at the 7d after the reperfusion to measure the protein GAP-43and SYN levels by immunohistochemistry and Western blot technology. Changes in these parameters and effects of rTMS on these parameters were analyzed.Results:The results showed that ischemia reperfusion injury produced distinct focal infarction,neurological deficits,different degree of cerebral edema and there is a highly mortality in 24h after the injury,rTMS could lower the death rate,reduce ischemic cerebral edema and decrease the expression of the protein AQP4 of the rats at the acute stage of ischemia stroke.The effect of rTMS group with high frequency and high intensity was statistically better than the sham-rTMS group(P＜0.05). rTMS continuously could improve rehabilitation of neurofunction and the expression of the protein GAP-43and SYN.The effect of rTMS group with high frequency and high intensity was statistically better than the sham- rTMS group(P＜0.05).Conclusion:The application of rTMS could lower the death rate of the acute stage of ischemia stroke.The application of rTMS could reduce ischemic cerebral edema and decrease the expression of the protein AQP4.The application of rTMS continuously could improve rehabilitation of neurofunction.The application of rTMS continuously could enhance the expression of the protein GAP-43and SYN.The rTMS group with high frequency and high intensity show a superiority effect than other groups.更多还原