Expression of neurocan mRNA and ultrastructure of brain tissue after cerebral ischemia and reperfusion in stroke-prone renovascular hypertensive rats treated by electroacupuncture

We established a stroke-prone renovascular hypertensive rat model by bilateral constriction of the renal artery with sliver loop clips. After ten weeks, middle cerebral artery occlusion was induced for 2 hours. The rats then received electro-acupuncture at Baihui （DU 20） and Dazhui （DU 14） after onset of ischemia for 30 days. In situ hybridization study showed that electroacupuncture significantly reduced the number of neurocan mRNA-positive cells in the ischemic penumbra and hippocampal tissues of rats. Electron microscopy results demonstrated that the structure of neurons and blood vessels in the ischemic tissues were restored with electroacupuncture. Overall, these data suggest that electroacupuncture may protect neurons against ischemic reperfusion injury in stroke-prone renovascular hypertensive rats, which may be regulated by downregulation of expression of nerve inhibitory factor neurocan mRNA.

Effects of anisodamine on altered [Ca^(2+)]i and cerebral cortex ultrastructure following acute cerebral ischemia/reperfusion injury in rabbits

BACKGROUND： Calcium ion （Ca^2＋） overload plays an important role in cerebral ischemia/reperfusion injury. Anisodamine, a type of alkaloid, can protect the myocardium from ischemia and reperfusion injury by inhibiting intracellular calcium [Ca^2＋]i overload. OBJECTIVE： To investigate effects of anisodamine on [Ca^2＋]i concentration and cortex ultrastructure following acute cerebral ischemia/reperfusion in rabbits. DESIGN, TIME AND SETTING： Randomized and controlled trial was performed at the Department of Emergency, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology from September to December 2006. MATERIALS： Forty healthy rabbits were used to establish models of acute cerebral ischemia/reperfusion. Anisodamine was provided by Lianyungang Dongfeng Pharmaceutical Factory; Fura-2 was purchased from Nanjing Jiancheng Bioengineering Institute; dual-wave length fluorescent spectrophotometry system and DM-300 software were provided by Bio-Rad, USA; OPTON-EM10C transmission electron microscope was product of Siemens, Germany. METHODS： Forty rabbits were randomly divided into the following groups： sham operation, ischemia, ischemia/reperfusion, and anisodamine, with ten rabbits in each group. Models of complete cerebral ischemia injury were established. In addition, blood was collected from the femoral artery of rats in the ischemia/reperfusion and anisodamine groups to induce hypotension and establish repeffusion injury models. The bilateral common carotid artery clamp was removed from the anisodamine group 20 minutes after ischemia, and anisodamine （10 mg/kg body mass） was injected via the femoral vein. Rabbits in the sham operation group underwent only venous cannulation. MAIN OUTCOME MEASURES： [Ca^2＋]i concentration was determined using a dual-wave length fluorescent spectrophotometry system, and cortical ultrastructure was observed following uranyl-lead citrate staining. RESULTS： The levels of [Ca^2＋]i in the ischemia and ischemia/reperfusion groups were significantly increased, compared with the sham operation group （P 〈 0.01）, and the levels of [Ca^2＋]i in the anisodamine group were remarkably less than the ischemia and ischemia/reperfusion groups （P 〈 0.01）. Ultrastructural damage to the cortex was greatly aggravated with increasing levels of [Ca^2＋]i. In the ischemia group, cortical neuronal membranes were fragmentally damaged, including the mitochoudria and endoplasmic reticulum, as well as neufite swelling, and slight chromatin margination. In the ischemia/reperfusion group, the cellular membrane was ruptured with aggravated mitochondrial swelling, increased chromatin margination, obscure neufite structure, and the disappearance of endoplasmic reticulum. However, in the anisodamine group, cellular damage was obviously alleviated. The appearance and structure of cortical neurons was relatively normal, with intact cells. There was slight swelling of the mitochondria and endoplasmic reticulum, as well as mild chromatin margination. CONCLUSION： Cerebral tissue injury was related to increased [Ca^2＋]i levels following ischemia/ reperfusion. Anisodamine exhibited a protective role on acute cerebral ischemia/reperfusion injury by inhibiting the increase in [Ca^2＋]i levels.

Electroacupuncture preconditioning protects against focal cerebral ischemia/reperfusion injury via suppression of dynamin-related protein 1

Electroacupuncture preconditioning at acupoint Baihui （GV20） can reduce focal cerebral ischemia/reperfusion injury. However, the precise protective mechanism remains unknown. Mitochondrial fission mediated by dynamin-related protein 1 （Drp1） can trigger neuronal apoptosis following cerebral ischemia/reperfusion injury. Herein, we examined the hypothesis that electroacupuncture pretreatment can regulate Drp1, and thus inhibit mitochondrial fission to provide cerebral protection. Rat models of focal cerebral ischemia/reperfusion injury were established by middle cerebral artery occlusion at 24 hours after 5 consecutive days of preconditioning with electroacupuncture at GV20 （depth 2 mm, intensity 1 mA, frequency 2/15 Hz, for 30 minutes, once a day）. Neurological function was assessed using the Longa neurological deficit score. Pathological changes in the ischemic penumbra on the injury side were assessed by hematoxylin-eosin staining. Cellular apoptosis in the ischemic penumbra on the injury side was assessed by terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling staining. Mitochondrial ultrastructure in the ischemic penumbra on the injury side was assessed by transmission electron microscopy. Drp1 and cytochrome c expression in the ischemic penumbra on the injury side were assessed by western blot assay. Results showed that electroacupuncture preconditioning decreased expression of total and mitochondrial Drp1, decreased expression of total and cytosolic cytochrome c, maintained mitochondrial morphology and reduced the proportion of apoptotic cells in the ischemic penumbra on the injury side, with associated improvements in neurological function. These data suggest that electroacupuncture preconditioning-induced neuronal protection involves inhibition of the expression and translocation of Drp1.

Ultrastructural changes of rat cortical neurons following ligustrazine intervention for cerebral ischemia/reperfusion injury

BACKGROUND： Ligustrazine can reduce the production of free radicals and the content of malonaldehyde, and improve the enzymatic activity of adenosine-triphosphate in cerebral anoxia. It also can increase the expression of heat shock protein-70 and Bcl-2, thus alleviating brain tissue injury caused by cerebral ischemia/reperfusion. This study aimed to address the question of whether ligustrazine can protect the membrane structure of neurons. OBJECTIVE： To establish rat models of cerebral ischemia/reperfusion, observe the membrane structure and main organelles of neurons with electron microscope after ligustrazine intervention, and to analyze the dose-dependent effects of ligustrazine on neuronal changes. DESIGN： A randomized controlled study. SETTING： Department of Anatomy Research and Electron Microscopy, Hebei North University. MATERIALS： Forty Wistar rats of SPS grade, weighing 180-250 g and equal proportion of female and male, were provided by Hebei Medical University Animal Center （No. 060126）. The ligustrazine injection （40 g/L, No. 05012） was produced by Beijing Yongkang Yaoye. LKB4 Ultramicrotome was purchased from LKB Company in Sweden. JEM100CXII electron microscope was purchased from JEOL in Japan. METHODS： The experiment was performed in the Laboratory of the Department of Anatomy and Electron Microscopy, Hebei North University from June to August 2006. （1） Wistar rats were allowed to adapt for 3 days, and were then randomly divided into four groups, according to the numeration table method： normal group, model group, low-dose ligustrazine group, and high-dose ligustrazine group. There were 10 rats in each group. （2）Rats in the model group, low-dose ligustrazine group, and high-dose ligustrazine group underwent cerebral ischemia/reperfusion model, according to Bannister＇s method. The carotid artery was opened for reperfusion after 90 minutes of cerebral ischemia. Samples were collected from the cerebral cortex after 24 hours. Animals from the ligustrazine low-dose group and ligustrazine high-dose group received ligustrazine injections, 50 mg/kg and 100 mg/kg, respectively. Samples were collected at the same time as the model group. MAIN OUTCOME MEASURES： Alterations of the neuronal ultrastructure and main organelles were observed by electron microscopy. RESULTS： Forty Wistar rats were included in the final analysis. Plentiful ribosome and rough endoplasmic reticulum existed in the cytoplasm of cortical neurons in the normal group. Edema existed in the nucleus and cytoplasm of neurons in the model group. The cell membrane was damaged, resulting in the external eruption of certain cellular organelles. In the low-dose ligustrazine group, neuronal swelling was decreased in the cytoplasm, whereas cellular organelles were relatively increased. However, the mitochondria remained swollen. The double layer structure disappeared in parts of the mitochondrial membrane. The caryotheca was still broken, and neuronal damage was significantly decreased in the high-dose ligustrazine group. In addition, cytoplasmic swelling was reduced andmost part of caryotheca was complete. Fragmentation of the cellular membrane was not detected. Mitochondrial cristae and the lysosome could also be detected. The number of rough endoplasmic reticulum and free ribosomes was increased, and the structure of great part of caryotheca was clear. In addition, the number of nuclear pore was increased. However, the nuclear heterochromatin was relatively reduced. CONCLUSION： In the rat, the protective effects of ligustrazine were significant on neuronal membrane structures and main organelles after cerebral ischemia/reperfusion. There was a dose-dependent effect between neuronal changes and Ligustrazine.

Changes in corticocerebral morphology in a rat model of focal cerebral ischemia/reperfusion injury following “Xingnao Kaiqiao” acupuncture

BACKGROUND： Cerebral ischemia/reperfusion injury has been shown to induce inflammatory reactions, including white blood cell activation and adhesion molecule expression. These reactions often lead to aggravated neuronal injury. OBJECTIVE： To observe corticocerebral pathology, as well as ultrastructural changes, in a rat model of focal cerebral ischemia/reperfusion injury through optical and electron microscopy, and to investigate interventional effects of ＂Xingnao Kaiqiao＂ acupuncture （a brain-activating and orifice-opening acupuncture method）. DESIGN, TIME AND SETTING： A randomized, controlled, neuropathology, animal experiment was performed at the Laboratory of Molecular Biology, First Affiliated Hospital of Tianjin University of Traditional Chinese Medicine between April and June 2004. MATERIALS： A total of 50 healthy, male, Wistar rats were randomized into 5 groups, with 10 rats per group： control, sham-operated, model, non-acupoint, and ＂Xingnao Kaiqiao ＂. Transmission electron microscope （TEM 400ST） was provided by Philips, Netherlands. Electro-acupuncture treatment apparatus （KWD-8082） was provided by Changzhou Wujin Great Wall Medical Instrument, China. METHODS： Focal cerebral ischemia/reperfusion injury was induced by occlusion of the middle cerebral artery in the model, non-acupoint, and ＂Xingnao Kaiqiao＂ groups. Rats from the control group did not undergo any treatment. The sham-operated group received identical experimental procedures as the model group, except that the nylon suture was not inserted into the right internal carotid artery. At 1, 3, 6, and 12 hours following focal cerebral ischemia/reperfusion injury induction, rats from the Xingnao Kaiqiao group underwent 1-minute acupuncture at the bilateral ＂Neiguan＂ （PC 6） acupoint, using a reducing method of lifting-thrusting and twirling-rotating. Subsequently, the rats were subjected to acupuncture at the ＂Renzhong＂ （DU26） acupoint 10 times by a heavy bird-pecking method. The non-acupoint group received acupuncture administration at the bilateral costal region. MAIN OUTCOME MEASURES： After ischemia for 1 hour and reperfusion for 24 hours, corticocerebral morphology and ultrastructural changes were observed on the injured side through the use of optical and electron microscopy. RESULTS： Cerebral ischemia/reperfusion resulted in damage to neurons, glial cells, and capillary vessels in the rat brain. ＂Xingnao Kaiqiao＂ acupuncture produced superior curative effects when it was performed 3 hours after cerebral ischemia/reperfusion induction, resulting in slightly recovered neuronal structures, alleviated cellular interstitial edema, and more capillary vessels. At each corresponding time point, the ＂Xingnao Kaiqiao＂ group exhibited improved neuronal structure and cellular interstitial edema, compared with the non-acupoint group. CONCLUSION： ＂Xingnao Kaiqiao＂ acupuncture results in protective effects on corticocerebral neuronal morphology and ultrastructure in rats following focal cerebral ischemia/reperfusion.

EFFECT OF ELECTROACUPUNCTURE ON SYNAPTIC PLASTICITY OF HIPPOCAMPAL NEURONS IN CEREBRAL ISCHEMIA RATS

Objective: To observe the effect of electroacupuncture (EA) on synaptic structure of hippocampal nerve felts and synaptophysin(SYN)expression in rats with cerebral ischemic injury. Methods: Sixty Wistar rats were randomized into sham-operation group, cerebral ischemia (CI) group and EA group, each of which was further divided into 1week (W) and 5W subgroups. CI injury model was established by occlusion of the bilateral common carotid arteries. 'Baihui'(百会 GV 20), 'Dazhui' (大椎 GV 14), 'Renzhong'(人中 GV 26) and 'Guangyuan'(关会 CV 4) were punctured and stimulated electrically. The brain tissue sections containing hippocampus region were stained with immu nohistochemical technique and observed under light microscope and transmission electronic microscope. Results: After CI, the ischemic injury as degeneration of the presynapse compositions, decrease of the synaptic numeral density, and low expression of SYN were observed in hippocampal CA1 area. By the 5th week after CI, the neonatal synapses of Cl and EA groups appeared, and SYN expression was upregulated. In EA group, the recovery of the numeral density of synapses was especially noticeable, being 93.8% of that of sham-operation group and significantly higher than that in Cl group (P<0.01). Compared with sham-operation group, the calibrated optical density (COD) values of SYN increased to 70% in CI group, and 93.3% in EA group, and COD value in EA group was significantly higher than that in Cl group (P<0.01). Conclusion: EA can function in promoting synaptic regeneration and enhancing and perfecting the actions of the reconstructed synapses in hippocampal CA1 area in Cl rats.

电针对脑缺血再灌注大鼠脑皮层超微结构及Nogo-A表达的影响

目的探讨电针对脑缺血再灌注(ischemia reperfusion,IR)大鼠不同时间点皮层超微结构及轴突再生抑制因子Nogo-A表达的影响。方法 130只雄性SD大鼠随机数字表法分为电针组(30只)、假穴位组(30只)、模型组(30只)、假手术组(30只)和空白组(10只)。电针、假穴位、模型3组采用改良的ZeaLonga法制备左侧大脑中动脉闭塞(middle cerebral artery occlusion,MCAO)模型。电针组术后选取督脉"大椎"、"百会"穴每天给予电针治疗。假穴位组术后选取督脉"大椎"、"百会"穴旁开1寸处给予电针治疗。模型组仅作MCAO缺血再灌注模型处理,假手术组仅做手术创伤,空白组不作任何处理。运用免疫组织化学染色法及透射电镜技术观察电针对IR后1、7、28d各组大鼠脑皮层缺血区细胞超微结构及Nogo-A表达的干预作用。结果电针组脑皮层缺血区神经元、胶质细胞及血脑屏障等超微结构的损伤均较假穴位组、模型组减轻。电针组大鼠脑缺血再灌注后第1、7、28d脑皮层缺血区Nogo-A的表达均低于同期假穴位组及模型组,差异有统计学意义(P<0.05),但假穴位组与模型组同期比较,差异无统计学意义(P>0.05)。结论电针对大鼠脑缺血再灌注损伤的保护作用,可能与其减轻脑细胞超微结构的损害、下调中枢神经轴突再生抑制因子Nogo-A的表达等机制密切相关。

MCAO大鼠梗死灶对侧皮层Nogo-A的动态变化及电针干预

目的观察脑缺血再灌注大鼠梗死灶对侧皮层不同时期轴突生长抑制因子Nogo-A的动态变化,并探讨电针对梗死灶对侧皮层Nogo-A的调节作用。方法采用改良Zea Longa法制备左侧大脑中动脉闭塞再灌注模型。采用免疫组织化学染色法及透射电镜技术观察电针对IR后1、7、28d各组大鼠脑梗死对侧皮层轴突再生抑制因子Nogo-A表达及神经元细胞形态、超微结构的影响。结果 (1)电针、假穴位、模型3组大鼠与假手术组大鼠相比,在IR后1d、7d梗死对侧皮层Nogo-A的表达均升高(P<0.05),7d最明显,第28天下降至基础水平(P>0.05);电针组大鼠IR后1d、7d脑梗死对侧皮层Nogo-A的表达均低于同期模型组和假穴位组,差异有统计学意义(P<0.05),但假穴位组与模型组同期对比差异无统计学意义(P>0.05)。(2)电针、假穴位、模型3组各时间点大鼠脑梗死对侧皮层出现神经元细胞胞体肿胀、细胞器水肿、核染色质轻度溶解、毛细血管内皮细胞肿胀、管腔狭窄等轻度病理改变,以缺血再灌注后第7天最明显,28d明显减轻。上述病理改变均较同期脑缺血区病变程度明显减轻,且不足以引起支配侧肢体神经功能缺失。电针组大鼠脑梗死对侧皮层神经元细胞、超微结构的改变均较同期模型组、假穴位组减轻。结论电针治疗脑梗死的有效机制可能与其减轻脑细胞超微结构的损害、下调中枢神经轴突生长抑制因子Nogo-A的表达、诱导神经轴突再生、减轻脑梗死后的远隔损害等密切相关。

脑缺血再灌流期NO分泌与脑血管反应

目的:探讨NO是否参与脑缺血再灌期脑血管反应。方法:采用激光多普勒、电化学和超微病理方法分别测量和观察沙土鼠软脑膜微血管管径、NO含量和脑皮层微血管超微结构的变化。结果:脑缺血初期,细动脉呈线状收缩。缺血(50±10)min时,细动脉扩张至最大值,此时NO合成也增加至最大值。而后细动、静脉缓慢收缩,至缺血2h,细动、静脉呈节段性痉挛状态;同时,NO合成减少;微血管内皮细胞严重受损。缺血30min再灌流5min,NO分泌增加,细动、静脉扩张:缺血2h再灌流5min,NO合成减少,细动脉收缩。结论:轻度缺血时,NO合成增加,参与脑血管扩张反应;重度脑缺血时,沙土鼠微血管BC的结构严重受损,O2-NO通路中断,参与“盗血”反应。

STUDY ON PROTECTIVE ACTION OF ELECTROACUPUNCTURE ON INJURY OF NEURONS IN RATS OF FOCAL ISCHEMIA BY MICROSCOPY AND ELECTRON MICROSCOPY

In rats of focal cerebal ischemia induced by occluding middle cerebral artery, therapeutic actions of el ectroacupuncture (EA) on injury of neurons were observed by microscopy and electron microscopy. As a results, 1. Each dimension of three-dimensional space in the cerebral infarct area in the EA group was smaller than that in the ischemic group; 2. It was found by microscopy that in the ischemic group, the cerebral infarct area was significantly larger than that in the EA group, some reaching in depth to the basal ganglion, with exfoliation of cerebral cortical infarct, most occurring sheet hemorrhagic focus, more leukocyte, mononuclear leukocyte and lymphocyte infiltration, capillary congestion and capillarectasia. In the EA group only a small part of hemorrhagic focus and less white blood cell, mononuclear cell and lymphocyte infiltration were seen; 3. It was found by H-800Electromicroscopy that in the ischemic group, structures of cell organs of most neurons disintegrated,with unclear structures of cytomembrance and nuclear membrance, some neurons showed pyknotic form and some cellular structures were unclear in the marginal zone of the cerebral ischemic region.However, in the EA group, structures of most neurons and cell organs were complete, with edema of some mitochondria, showing spheroid, and rupture of some mitochondrial cristae in the marginal zone of ischemic region. The results indicate that EA can protect neurons after cerebral ischemia against secondary injury.

三七皂苷对脑梗塞所致神经功能障碍的影响

目的 :研究不同剂量的三七皂苷 (PNS)对局灶脑缺血所造成的神经功能障碍及超微结构的影响作用。方法 :Wistar大鼠 3 5只 ,随机分组。按照文献制备可逆性大脑中动脉梗塞 (MCAO)性脑缺血模型。利用诱发电位肌电图测试仪 ,测各组MCAO前后SEP的变化 ,脑皮质NO、SOD含量 ,及电镜超微结构的改变 ,观察三七皂苷对MCAO性脑损伤的保护作用。结果 :PNS 4 0 0mg·kg-1、2 0 0mg·kg-1均能明显缩短MCAO后SEP潜伏期时间 ,降低缺血区NO含量 ,增加SOD活性。与对照组比较有显著统计学意义 (P <0 .0 1) ,超微结构研究显示 ,三七皂苷能明显减轻缺血脑组织细胞损伤及神经元的坏死程度。结论 :三七皂苷能减轻局灶性脑缺血所造成的神经功能障碍。作用机理可能与增加SOD活性 ,降低脑NO含量 ,阻止Ca2 +内流有关。

老龄大鼠脑缺血-再灌注神经细胞凋亡变化规律研究

目的 比较研究青年与老龄大鼠脑缺血再灌注 (I/R)后超微结构与神经细胞凋亡特征。方法 采用线栓法建立急性局灶性脑缺血再灌注损伤模型 ,观察缺血 3h及再灌注 3、6、12、2 4和 72 h脑组织超微结构变化及细胞凋亡。结果 老龄大鼠脑缺血 3h和 I/R12 h脑梗死面积较青年大鼠增大。随着 I/R时间延长 ,脑组织细胞损伤逐步加重 ,老龄大鼠较青年大鼠严重。细胞凋亡随着 I/R时间延长而明显增加 ,老龄大鼠出现的早、持续时间长。结论 老年脑缺血再灌注脑梗死面积增大、超微结构损伤和细胞凋亡出现得早且严重。

高压氧减轻沙土鼠脑缺血时脑组织间隙水肿机制的研究

目的 探讨高压氧减轻脑组织间隙水肿的作用机制。方法 采用激光多谱勒和电镜方法 ,测量沙土鼠软脑膜微血管管径和观察脑微血管超微结构的变化。结果 脑缺血 30min再灌注 ,脑微动、静脉明显扩张 ,同时 ,血管周隙严重水肿。脑缺血的沙土鼠在高压氧 ( 0 .2MPaO2 )下暴露 30min ,微动脉收缩 ,微静脉无明显变化 ,血管周隙水肿消退。结论 在高压氧状况下 ,脑微动脉收缩 ,毛细血管内血压下降 ,有利于组织液吸收 。

氨基胍对局灶性脑缺血大鼠线粒体损伤的影响

目的观察选择性诱生型一氧化氮合酶抑制剂氨基胍(aminoguanidine,AG)对局灶性脑缺血大鼠脑线粒体损伤的作用,探讨其改善缺血性脑损伤的作用机制。方法将大鼠随机分为假手术组、缺血对照组、AG治疗组,采用线栓法复制大鼠大脑中动脉栓塞(MCAO)模型,分别于缺血后2、6、12h给药治疗3d,迅速断头取脑,差速离心法提取缺血侧脑组织线粒体,测定线粒体总ATP酶、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSHPx)活性,以及线粒体一氧化氮(NO)、丙二醛(MDA)含量;电镜观察了缺血后皮层神经元超微结构的改变及AG对此改变的影响。结果在大鼠MCAO后线粒体NO生成明显增加,线粒体总ATP酶、SOD、GSHPx活性均有明显下降,线粒体MDA含量明显升高;缺血2、6、12h给予AG治疗3d与缺血对照组相比NO生成有所下降,总ATP酶、SOD、GSHPx活性均升高,MDA含量下降。电镜结果显示脑缺血后皮层神经元水肿,线粒体肿胀、嵴断裂、溶解、消失,且随缺血时间延长损伤加重;AG能明显改善脑缺血引起的神经元水肿、线粒体肿胀和空泡化。结论AG能明显抑制脑缺血后线粒体NO生成,改善线粒体能量供应,增加线粒体抗氧化作用,从而减轻脑缺血损伤。

褪黑素对大鼠局灶性脑缺血的影响

目的 :探讨褪黑素对大鼠局灶性脑缺血保护作用。方法 :用线栓法建立大鼠大脑中动脉栓塞 (MCAO)模型。大鼠随机分为假手术组、缺血组、褪黑素组 (4mg·kg 1 )、尼莫地平组 (0 .2mg·kg 1 )。缺血前 3 0min舌下静脉给药。持续性缺血 3 0min ,6,2 4h后处死动物 ,测定脑梗死体积 ,脑组织丙二醛 (MDA)、一氧化氮 (NO)含量和NOS活性 (分光光度法 ) ;透射电镜观察脑组织超微结构改变。结果 :MCAO后 ,脑梗死体积及MDA含量随时间延长而增大 ,6h后基本稳定 ;缺血 3 0minNO含量及NOS活性升高 ,缺血 6h降低 ,2 4h再度升高。与模型组比较 ,褪黑素组能缩小脑梗死体积、降低脑组织中MDA含量、缺血 3 0minNO含量及NOS活性升高 ,6,2 4h降低 ,且显著改善脑组织的超微病变 ,减少神经细胞的凋亡。结论 :褪黑素对大鼠局灶性脑缺血有一定的保护作用 ,机制可能与降低脑组织中NO含量和NOS活性、减轻脑组织生物膜脂质过氧化损伤及减少神经细胞的凋亡有关。

黄芩苷对大鼠缺血再灌注脑组织TNF-α、IL-1β表达的影响

目的探讨黄芩苷对大鼠缺血再灌注脑组织TNFα、IL1β的表达和脑水肿及超微结构的影响。方法采用大脑中动脉缺血再灌注模型,先将大鼠随机分为假手术组、缺血再灌注组及黄芩苷治疗组,再用免疫组化法检测脑组织缺血再灌注3、6、24hTNFα和IL1β的表达,用称重法测定缺血再灌注3、6h脑组织含水量,电子显微镜观察缺血再灌注24h脑组织的超微结构及黄芩苷对其影响。结果TNFα和IL1β在缺血再灌注3、6、24h明显表达,黄芩苷治疗组的表达较之明显降低(P<0.01);缺血再灌注3、6h脑组织含水量明显增高,黄芩苷治疗组脑组织含水量较之明显降低(P<0.05,P<0.01);脑组织超微结构显示:神经细胞肿胀、损伤以及细胞迟发性死亡程度显著减轻。结论黄芩苷能降低脑缺血再灌注后TNFα、IL1β的表达,具有一定的脑组织保护作用。

冰片与川芎配伍对脑缺血再灌注损伤的保护作用

用结扎双侧颈总动脉法 ,造成大鼠脑缺血再灌注模型 ,观察冰片与川芎配伍对急性脑缺血再灌注脑组织含水量、形态学及超微结构的影响。结果显示 ,冰片与川芎配伍可明显减轻缺血再灌注脑组织含水量 ;明显减轻细胞间质水肿和神经细胞的损伤 ;对脑缺血再灌注所致脑组织超微结构的破坏也有明显的保护作用。提示冰片与川芎配伍可通过保护血管内皮细胞功能、基膜的完整性 ,改善微循环 ,减轻脑水肿程度 ,从而对脑缺血再灌注损伤起保护作用。冰片与川芎配伍后 。

电针对局灶性脑缺血大鼠皮层体感诱发电位和细胞超微结构的影响

采用凝闭大鼠大脑中动脉致局灶性脑缺血模型,研究电针督脉经“大椎”、“人中”两穴对皮层体感诱发电位(SEP)和细胞超微结构的影响,结果显示,缺血组SEP各成分波幅明显降低,峰潜伏期明显延长,细胞超微结构大部分崩解;电针组SEP各成分波幅略有降低,但峰潜伏期无明显延长,细胞超微结构大部分未破坏。表明电针可阻止神经元继发坏死,为针灸治疗缺血性中风提供理论依据。

针刺大椎、人中、百会穴对脑缺血再灌注损伤大鼠脑线粒体超微结构的影响

目的观察针刺大椎、人中、百会穴对脑缺血再灌注后大鼠脑线粒体超微结构的影响,探讨针刺对脑缺血再灌注损伤的部分作用机制。方法 40只大鼠随机挑选10只为假手术组,其余30只大鼠造模后随机分为模型组、针刺对照点组、针刺穴位组3组,每组10只。大鼠造模成功后,模型组、假手术组只捆绑不针刺,针刺穴位组针刺大椎、人中、百会三穴,针刺对照点组针刺针刺穴位左侧旁开0.3 cm处,每12小时针刺1次,6次治疗后处死大鼠,取缺血海马组织电镜下观察线粒体超微结构。结果治疗后,除假手术组外其余各组大鼠神经功能缺损评分均下降(P<0.05);与模型组比较,针刺穴位组和针刺对照点组均下降更明显(P<0.05)。电镜观察结果显示,假手术组线粒体结构正常;模型组线粒体肿胀明显,嵴断裂,空泡结构明显;针刺对照点组线粒体肿胀,可见嵴断裂,少量空泡结构;针刺穴位组线粒体稍肿胀,嵴断裂及空泡化不明显。结论针刺能减轻脑缺血再灌注损伤,其机制可能与改变缺血再灌注局灶的线粒体超微结构损伤有关。

补阳还五汤对沙鼠脑缺血后海马CA1区细胞形态结构与细胞凋亡的影响

目的 研究补阳还五汤对沙鼠脑缺血损伤后海马CA1区细胞形态结构与细胞凋亡的影响。方法 采用沙土鼠双侧颈总动夹闭脑缺血再灌注模型,于再灌注后120 h取大脑半球, 在解剖显微镜下定位海马,切取海马,切片机切片后观察神经细胞超微结构和神经细胞凋亡情况。结果 补阳还五汤可使海马CA1区神经细胞和毛细血管变性、死亡减轻, 并可使海马CA1区神经细胞的凋亡数目明显减少。结论 补阳还五汤可能通过减轻神经元的溃变、死亡,减少神经细胞的凋亡而发挥抗脑缺血的作用。