Effect of nicorandil on infarct volume and marker enzyme activity in mitochondria of rats with cerebral ischemia/ reperfusion injury★

BACKGROUND： Recent studies have suggested that mitochondrial ATP-sensitive K＋ channel openers could reduce myocardium infarct size, and protect the function of the mitochondria. OBJECTIVE： To investigate the changes of cerebral infarction volume and the activity of marker enzymes in brain mitochondria of rats given the ATP-sensitive K＋ channel opener, nicorandil, before focal cerebral ischemia/reperfusion （I/R）. DESIGN, TIME AND SETTING： Randomized, controlled animal experiment, completed at the Brain Scientific Research Center of the Affiliated Hospital of Qingdao University from July to November 2007. MATERIALS： Sixty healthy male Wistar rats weighing 280-300 g. Nicorandil, 5-hydroxydecanoate （5-HD） and cytochrome C were purchased from Sigma in the USA. Standard malondialdehyde （MDA） and protein were purchased from Nanjing Jiancheng Biotechnology Institute. METHODS： Sixty rats were randomly divided into a sham operation group, a middle cerebral artery occlusion （MCAO） group, a nicorandil group and a nicorandil＋5-HD group. MCAO for 2 hours was performed in the MCAO group, nicorandil group and nicorandil＋5-HD group. A total of 5 mL saline were given to the MCAO group before MCAO. The nicorandil group was injected with the ATP-sensitive K＋ channel opener nicorandil 10 mg/kg intraperitoneally 30 minutes before MCAO. The nicorandil＋5-HD group was injected with 5-HD 10 mg/kg intravenously 15 minutes before the same treatment as the nicorandil group. MAIN OUTCOME MEASURES： Infarct volume by total brain slice calculation, activities of succinate dehydrogenase （SDH） and cytochrome oxidase （CO）, and content of MDA were observed at 22 hours of reperfusion after 2 hours MCAO. RESULTS： Sixty rats were included in the final analysis, without any loss. （1） Infarct volume： compared with the MCAO group and nicorandil＋5-HD group, the percentage of infarct volume was significantly decreased in the nicorandil group （P 〈 0.01）. （2） The content of MDA, expression of     

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     

Effects of phycocyanin on apoptosis and expression of superoxide dismutase in cerebral ischemia reperfusion injury

IN T R O D U C T IO NSuperoxide dism utase (SO D )is an im portantendogenous free radica scavenger, itelim inates superoxide anion free radicals through dis proportionation, and itprotects the nerve cells in the process ofcere bralischem ia reperfusion in…     

Effects of strain, body mass, and thread tip preparation on the establishment of focal cerebral ischemia mouse models*★

BACKGROUND: What are the successful factors of the establishment of the thread-blocking method for focal cerebral ischemia/reperfusion mouse models? OBJECTIVE: To study the effects of strain, body mass, and thread tip preparation for the establishment of focal cerebral ischemia mouse models by using middle cerebral artery occlusion (MCAO). DESIGN: Observational contrast animal study. SETTING: Gulou Hospital, Medical College of Nanjing University. MATERIALS: ①　The following experiment was performed at the Animal Experimental Center, Gulou Hospital Affiliated to Medical College of Nanjing University from December 2006 to April 2007. Sixty male white Kunming mice, whose body masses were 18–22 g (n =40), 25–29 g (n =10) and 30–33 g (n =10), as well as 10 male C57BL/6J mice, whose body mass was 18–22 g, were provided by the Animal Experimental Center, Gulou Hospital Affiliated to Medical College of Nanjing University. All mice were 10–12 weeks old. The project received confirmed consent from the local ethics committee. ②Experimental materials: tripheryltetrazolium hydrochloride (TTC) and 0.1% poly-L-lysine were provided by Sigma Company, USA; citromint was provided by Shanghai Lingfeng Chemical Company Limited. METHODS: ① Strain comparison: Ten white Kunming mice (weighing 18–22 g) and ten C57BL/6J mice (weighing 18–22 g) were selected. ② Comparison of body mass: Thirty white Kunming mice, whose body masses were 18–22 g (n =10), 25–30 g (n =10), and 30–35 g (n =10), were divided into groups. ③ Comparison of thread tip preparation: White Kunming mice weighing 18–22 g were divided into a poly-L-lysine line group and general line group, with 10 mice in each group. Mice in these two groups, which were respectively treated with poly-L-lysine or nothing, underwent MCAO. ④ All experimental mice received MCAO. Three hours after ischemia, and 24 hours after reperfusion, neurological deficit scores were measured and a success rate of model establishment was calculated. In addition, after sacrifice, sample tissues were cut into coronal sections to calculate the cerebral infarction area. MAIN OUTCOME MEASURES: ① Success rate of model establishment and cerebral infarction area. ② Neurological deficit scores. RESULTS: Sixty white Kunming mice and 10 C57BL/6J mice were included in the final analysis. ① Strain comparison: The cerebral infarction area of white Kunming mice was larger than the C57BL/6J mice, and the neurological deficit scores of white Kunming mice were greater than those of the C57BL/6J mice (P < 0.05). ② Comparison of body mass: A success rate of model establishment in white Kunming mice weighing 18–22 g was higher than in white Kunming mice weighing 25–30 g or 30–35 g (P < 0.05). ③ Comparison of thread tip preparation: The cerebral infarction area of mice in the poly-L-lysine line group was larger than in mice in the general line group. The neurological deficit scores of mice in the poly-L-lysine line group were greater than in mice in the general line group (P < 0.05). CONCLUSION: Strain, body mass, and thread tip preparation can affect the establishment success rate of a focal cerebral ischemia mouse model using MCAO. Key Words: mice; ischemia/reperfusion; animal model; thread-blocking method     

Effects of Chuanxiongqin hydrochloride on increasing the fluidity of brain cell membrane and scavenging free radicals in model rats with ischemia/reperfusion injury

BACKGROUND: The fluidity of cell membrane can be affected by various factors. Many experiments have confirmed that the ischemia/reperfusion of organic tissue can increase the contents of free radicals, which lead to high rigidity and low fluidity of cell membrane, and the conditions can be changed by Chuanxiongqin. OBJECTIVE: To observe the effect and mechanism of Chuanxiongqin hydrochloride on the fluidity of brain cell membrane in rat models of ischemia/reperfusion. DESIGN: A completely randomized controlled animal trial. SETTINGS: Institute of Brain Sciences; Department of Physiology, Medical College, Datong University. MATERIALS: Twenty male grade Ⅰ Wistar rats of 170-220 g were randomly divided into model group (n =10) and control group (n =10). Chuanxiongqin hydrochloride (molecular mass was 172.2) was purchased from the National Institute for the Control of Pharmaceutical and Biological Products (batch number: 0817-9803); Spin labelers: 5-doxyl-stearlic acid methylester (5DS), 16-doxyl-stearlic acid methylester (16DS), xanthine, xanthine oxidase (XOD) and 5,5-dimeth-1-pyrroline- N-oxide (DMPO) from Sigma Company; Bruker ESP 300 electron paramagnetic resonance (EPR) spectrometer by Bruker Company (Germany). METHODS: The experiments were carried out in the State Key Laboratory of Natural and Biomimetic Drugs, Peking University from June 2001 to July 2002. In the model group, rats were made into models of cerebral ischemia by 30-minute ligation and 2-hour reperfusion of common carotid arteries; The rats in the control group were not made into models. The order parameter (S) and rotational correlation time (τc) were detected with the ESR spectrometer by means of spin labeling. The greater the S and τc, the smaller the fluidity. Meanwhile, the clearance rate of free radicals was detected with ESR spin trapping. The measurement data were compared using the t test. MAIN OUTCOME MEASURES: The S, τc and clearance rates of O2 · and OH· free radicals were compared between the model group and control group. RESULTS: The S and τc in the model group [0.738 4±0.003 5; (8.472±0.027)×10-10 s/circle] were obviously different from those in the control group [0.683 9±0.008 3; (7.945±0.082)×10-10 s/circle, t =5.731, 5.918, P < 0.05], which suggested that ischemia/reperfusion injury decreased the fluidity of brain cell membrane. After adding Chuanxiongqin hydrochloride, there were no obvious differences between the model group [0.688 5±0.030 5; (7.886±0.341)×10-10 s/circle] and control group (P > 0.05), indicating that Chuanxiongqin hydrochloride could recover the fluidity of brain cell membrane after ischemia/reperfusion injury close to the level in the normal control group. Chuanxiongqin hydrochloride could directly scavenge the O2 · and OH· free radicals, and the maximal clearance rates were 83.92% and 44.99% respectively. CONCLUSION: Chuanxiongqin hydrochloride increases the fluidity of membrane of ischemia-injured brain cell by scavenging both O2 ·and OH· free radicals.     

Effect of pre-ischemia on hypoxia-inducible factor expression in the brain tissue of rats with cerebral ischemia/reperfusion injury

BACKGROUND: Hypoxia-inducible factor 1 (HIF-1) can lead to the adaptative reaction of body for hypoxia and ischemia. HIF-1 plays an important role in the response of ischemia-hypoxia. At present, there has been no overall report on the significance for the expression of HIF-1 following experimental cerebral ischemia. OBJECTIVE: To observe the expression of HIF-1 after middle cerebral artery occlusion (MCAO) by immunohistochemical method. DESIGN: Completely randomly grouped controlled animal experiment. SETTING: Second Hospital, Xi'an Jiaotong University. MATERIALS: Thirty-six Sprague-Dawley healthy male rats, with body mass of 250–330 g, were used in this study. Thirty-six rats were randomized into 3 groups: pre-ischemia group, sham-operation group and control group, with 12 rats in each. METHODS: This study was carried out in the clinical laboratory, People's Hospital of Ningjin County of Shandong Province from March 2006 to January 2007. Rats in the pre-ischemia group were created into pre-ischemia models by two embolisms twice. Three days after ischemic preconditioning, middle cerebral artery (MCA) was occluded for 2 hours with the same method. After being perfused for 22 hours, the rats were euthanized. In the sham-operation group, rats were not given the treatment of pre-ischemia. In the first operation, only common carotid artery (CCA) and its crotch were exposed in the first operation, and MCA was not blocked by inserting embolism. At postoperative 3 days, rats were euthanized after being subjected to MCAO for 2 hours and reperfusion 22 hours by the same procedure as that in the pre-ischemia group. As for each rat in the control group, only CCA and its crotch were exposed, and no any other treatment was carried out on them. MAIN OUTCOME MEASURES: Brain tissue of each rat was performed immunohistochemical staining at reperfusion 22 hours after pre-ischemia, HIF-1 expression and brain infarct volume were detected. RESULTS: Thirty-six Sprague-Dawley rats were involved in the experiment. During the experiment, 8 rats dropped out, and another 8 rats were supplemented. The infarct volume of rats in the pre-ischemia group was significantly smaller than that in the sham-operation group （t =3.22, P < 0.01）. HIF-1 expression was not found in the control group, but many HIF-1 positive cells were found in the other two groups. Absorbance in the pre-ischemia group was significantly higher than that in the sham-operation group (t =4.31, P < 0.01). CONCLUSION: Slight ischemia caused preconditioning can increase HIF-1 content, and it is one of protective mechanisms for nerve cells.     

Effects of Rubus parvifolius L. on neuronal apoptosis and expression of apoptosis-related proteins in a rat model of focal cerebral ischemic-reperfusion injury*★

BACKGROUND： Studies have shown that the Rubus parvifolius L. （RP） plant extract exhibits protective effects on cerebral ischemia. This effect is reflected in altered ischemic neuronal apoptosis and associated protein expression.
OBJECTIVE： To explore the neuroprotective mechanism of RP after cerebral ischemia injury.
DESIGN, TIME AND SETTING： Randomized control experiment of cellular, molecular, and protein levels. The experiment was completed at Chongqing Medical University at the School of Pharmacy Laboratories and Basic Medical Institute from October 2005 to January 2006.
MATERIALS： Twenty-four adult, male, Wistar rats, weighing （28 ± 20） g. RP extract, which was a product of ethanol extraction, was provided by the Laboratory of Pharmaceutical Analysis, Chongqing Medical University. RP was dissolved in distilled water to a concentration of 10 mg/mL. All rats were randomly assigned into four groups： 5 g/kg RP, 10 g/kg RP, model, and sham-surgery, with 6 rats in each group.
METHODS： In the 5 and 10 g/kg RP groups, as well as the model group, the middle cerebral artery was occluded （MCAO） for 60 minutes, resulting in focal cerebral ischemia, followed by reperfusion for 24 hours. Rats in the 5 and 10 g/kg RP groups received 5 and 10 g/kg RP, respectively. The RP treatment group received RP intragastrically （once a day） for 3 days. One hour after the last dose, rats were subjected to MCAO. The same surgical procedure was performed in the sham-surgery group, except the suture was introduced into the external carotid artery, but not advanced. Rats in the model group were subjected to MCAO. The sham-surgery and model groups received intragastrically administered normal saline once per day for 3 days. One hour after the last dose, the rats were subjected to surgery.
MAIN OUTCOME MEASURES： TUNEL labeling and immunohistochemical methods were used to investigate changes in neuronal apoptosis and expression of the apoptosis-related proteins, Bax and Bcl-2, on the ischemic hemisphere     

Effects of fastigial nucleus electrical stimulation on lateral ventricle nestin expression after focal cerebral ischemia/reperfusion in adult rats**★

BACKGROUND： Previous studies have confirmed that fastigial nucleus electrical stimulation can induce endogenous neuroprotective mechanisms and produce wide and long-lasting neuroprotective effects. Nevertheless, the precise mechanisms remain poorly understood. OBJECTIVE： This study was designed to observe the effects of fastigial nucleus electrical stimulation on nestin-positive cell expression in adult rat lateral ventricle after focal cerebral ischemia/reperfusion, as well as neurological functional changes as a function of time. DESIGN： A randomized controlled animal experiment. SETTING： Department of Neurology, First Affiliated Hospital of Chongqing Medical University; Chongqing Key Laboratory of Neurology. MATERIALS： This study was performed in the Department of Neurology, First Affiliated Hospital of Chongqing Medical University and Chongqing Key Laboratory of Neurology from September 2004 to February 2006. A total of 180 healthy, adult, male Wistar rats, aged 8 weeks old, were provided by the Laboratory Animal Center of Chongqing Medical University. The main reagents and equipments were as follows： rabbit anti-rat nestin monoclonal antibody （Wuhan Boster Company, China）. METHODS： The included male Wistar rats were randomly divided into 5 groups： normal control, sham-operated, model, fastigial nucleus sham-stimulation （sham-stimulation for short）, and fastigial nucleus electrical stimulation （stimulation for short） groups. Six time points （1 hour of ischemia and 1, 3, 7, 14, 21, and 28 days of reperfusion, 6 rats per time point） were allotted to each group. Cerebral ischemia/reperfusion was performed by occlusion to the right middle cerebral artery with suture, followed by suture removal. In the stimulation group, subsequent to reperfusion, the rat left cerebellar fastigial nucleus was immediately subjected to 1 hour of stimulation. After anesthesia, the rat left cerebellar fastigial nucleus was stimulated for 1 hour using a square-wave electronic stimulator with a current in     

Interventional effect of laser acupoint radiation on the expression of Nissl body and brain-derived neurotrophic factor in newborn rat models with ischemic/hypoxic cerebral injury

BACKGROUND: Some researches report that He-Ne laser can activate function of erythrocytes and increase content of blood and oxygen via bio-stimulating effect; therefore, it suspects that laser radiation at Baihui and Dazhui can partially increase blood circulation for oxygen-supplying content of brain and improve functional status of neurons. OBJECTIVE: To verify the effects of laser radiation at Baihui and Dazhui on the expression of Nissl body of brain tissue neurons and brain-derived neurotrophic factor (BDNF) in newborn rats with ischemic/hypoxic cerebral injury. DESIGN: Randomized controlled animal study. SETTING: Department of Neurological Histochemistry, Xianning University. MATERIALS: Forty Wistar rats of 7–8 days old, weighing 15–20 g and of both genders, were selected from Wuhan Experimental Animal Center. All the rats were randomly divided into sham operation group (n =8), model group (n =16) and radiation group (n =16). The experimental animals were disposed according to ethical criteria. BDNF kit was provided by Wuhan Boster Bioengineering Co., Ltd. METHODS: The experiment was carried out in the Department of Neurological Histochemistry, Xianning University from April 2005 to October 2006. Rats in the radiation group and model group were performed with ligation of left common carotid artery, recovered at room temperature for 1–6 days, maintained in self-made hypoxic cabin under normal pressure and injected mixture gas (0.05 volume fraction of O2 and 0.92 volume fraction of N2) for 2 hours. In addition, rats in the sham operation group were treated with separation of left common carotid artery but not ligation and hypoxia. Rats in the model group were not given any treatment; while, rats in the radiation group were exposed with He-Ne laser of 63.28 nm in the wave length at Baihui and Dazhui acupoints on the second day after ischemia-hypoxia. The radiation was given for 10 minutes per day and once a day. Ten days were regarded as a course and the rats were exposed for 2 courses in total. At 20 days after routine breeding, left hemisphere tissues of rats in the three groups were collected for staining of Nissl body and immunohistochemistry of BDNF. MAIN OUTCOME MEASURES: Nissl body staining in left hemisphere tissue and expression of immune positive cells of BDNF. RESULTS: All 40 rats were involved in the final analysis. ① Nissl body staining: Neuronal cytoplasm of brain tissue was full of blue granule Nissl bodies in the sham operation group; while, Nissl body in neuronal cytoplasm in the model group was stained slightly and had a certain degree of degeneration; meanwhile, there were a lot of blank area in ischemic region. Nissl body in neuron cytoplasm was gradually recovered in the radiation group and relieved as compared with that in the model group. ② Positive cells of BDNF: Number of immune positive cells of BDNF which were ligated in lateral cerebral hemisphere of rats in the model group was higher than that in the sham operation group (P < 0.05); while, BDNF expression in the radiation group was increased as compared with that in the model group (P < 0.05). CONCLUSION: After laser acupoint radiation, Nissl body is increased and BDNF expression is also increased. This suggests that laser acupoint radiation has neuroprotective effect on brain tissue after ischemia-hypoxia injury.     

Effects of transection of cervical sympathetic trunk on cerebral infarct volume and oxygen free radical levels in rats with focal cerebral ischemia/reperfusion injury

BACKGROUND: Stellate ganglion block (SGB) plays a protective role on the brain, but the precise mechanism of action is not clear.OBJECTIVE: To simulate SGB by transection of the cervical sympathetic trunk (TCST) and to investigate the TCST effects on changes in cerebral infarct volume and oxygen free radical levels in rats with focal cerebral ischemia/reperfusion injury.DESIGN, TIME AND SETTING: A complete randomized control animal experiment was performed at the Institute of Neurological Diseases of Taihe Hospital, Yunyang Medical College from February to December 2005.MATERIALS: A total of 101 healthy Wistar rats, weighing 280-320g, of both genders, aged 17-18 weeks, were used in this study. 2,3,5-triphenyltetrazolium chloride (TTC) was purchased from Changsha Hongyuan Biological Company. Superoxide dismutase (SOD), malondialdehyde (MDA) and nitric oxide (NO) assay kits were provided by Nanjing Jiancheng Bioengineering Institute.METHODS: Rats were randomly divided into a TCST group, a model group and a sham operation group. Successful models were included in the final analysis, with at least 20 rats in each group. After TCST, rat models of focal cerebral ischemia/reperfusion injury were established in the TCST group by receiving middle cerebral artery occlusion (MCAO) by the intraluminal suture method for 2 hours, followed by 24 hours of reperfusion. Rat models of focal cerebral ischemia/reperfusion injury were made in the model group. Rats in the sham operation group underwent experimental procedures as for the model group, threading depth of 10mm, and middle cerebral artery was not ligated.MAIN OUTCOME MEASURES: Brain tissue sections of ten rats from each group were used to measure cerebral infarct volume by TTC staining. Brain tissue homogenate of another ten rats from each group was used to detect SOD activities, MDA contents and NO levels. Rat neurological function was assessed by neurobehavioral measures.RESULTS: Cerebral infarct volume was bigger in the model group than in the TCST group (P<0.05). Twenty four hours after cerebral ischemia/reperfusion, SOD activities were lower, whereas MDA contents and NO levels were higher in the TCST and model groups, compared with the sham operation group (P<0.05 or P<0.01). Compared with the model group, SOD activities were higher, whereas MDA contents and NO levels were lower in the TCST group (P<0.05).CONCLUSION: After TCST, cerebral infarct volume is reduced, SOD activities are increased, and MDA contents and NO levels are decreased compared to the model group in rats with focal cerebral ischemia/reperfusion injury. These changes may be associated with TCST.     

Cervical sympathetic trunk transection affects inducible nitric oxide synthase expression in rat hippocampus following focal cerebral ischemia/reperfusion injury

BACKGROUND： The stellate ganglion block （SGB） plays a protective role in focal cerebral ischemia/reperfusion injury. The human SGB can be simulated by transection of the cervical sympathetic trunk （TCST） in rats. OBJECTIVE： To observe the effects of TCST on inducible nitric oxide synthase （iNOS） levels and cerebral infarct volume in the hippocampus of rats with cerebral ischemia/reperfusion injury, and to analyze the mechanism of action. DESIGN, TIME AND SETTING： A completely randomized, controlled, neuropathological experiment was performed at the Institute of Neurological Disease, Taihe Hospital, Yunyang Medical College between March and September 2006. MATERIALS： A total of 93 Wistar rats, aged 1718 weeks, of either gender, were used for this study. 2, 3, 5-triphenyl tetrazolium chloride was purchased from Changsha Hongyuan Biological Reagent Company China. Rabbit iNOS antibody and goat anti-rabbit IgG antibody were the products of Wuhan Boster Biological Reagent Co., Ltd., China. METHODS： Ten rats were randomly selected for the sham-operated group. Cerebral ischemia/reperfusion injury was induced by middle cerebral artery occlusion （MCAO） using the suture method in the remaining rats. Forty successful rat models were randomly and equally divided into the following two groups： （1） TCST group： subsequent to TCST, MCAO was performed for 2 hours, followed by 24 hours reperfusion; （2） model group： rats underwent experimental procedures similar to the TCST group, with the exception of TCST. Rats in the sham-operated group were subjected to experimental procedures similar to the model group; however, the thread was only introduced to a depth of 10 mm. MAIN OUTCOME MEASURES： Following 24 hours of reperfusion, functional neurological deficits were scored. Brain tissue sections from ten rats of each group were used to measure cerebral infarct volume by TTC staining. Hippocampal tissue sections of an additional ten rats from each group were used to detect iNOS levels using the s     

颈交感神经干离断对局灶性脑缺血再灌注后大鼠海马iNOS表达的影响

目的采用颈交感干离断（TCST）模拟星状神经节阻滞，观察其对局灶性脑缺血再灌注损伤（CIRI）大鼠脑梗死容积及海马诱导型一氧化氮合酶（iNOS）表达等的影响，并探讨其脑保护作用的机制。方法将大鼠随机分成实验组（A组）、对照组（B组）和假手术组（C组）；采用线栓法行大脑中动脉栓塞（MCAO）制作大鼠局灶性CIRI模型，A组于TCST后即行MCAO，2h后再恢复灌注；B组为单纯CIRI组；C组仅完成与A组相似的手术步骤但不造成MCAO、不行TCST；再灌注24h后观察各组大鼠神经行为学评分、脑梗死容积及海马iNOs的表达变化。结果A组大鼠脑梗死容积和神经行为学评分均低于B组（P〈0．05）；与A组、C组相比，B组大鼠海马iNOS的表达增加（P〈0．05），而A组与C组间无显著差异（P〉0．05）。结论TCST可通过下调大鼠海马iNOS的表达而对局灶性CIRI发挥脑保护作用。     

依达拉奉对脑缺血再灌注大鼠脑组织及血清超氧化物歧化酶、一氧化氮、丙二醛水平的影响

目的探讨依达拉奉对局灶性脑缺血再灌注损伤的影响。方法将SD大鼠分为假手术组,脑缺血再灌注组和依达拉奉干预组(干预组),采用线栓法制备大脑中动脉缺血再灌注模型;缺血1h后,设再灌注2h、6h、12h、24h组,采用化学比色法检测各组脑组织及血清超氧化物歧化酶(SOD)、一氧化氮(NO)、丙二醛(MDA)浓度。结果缺血再灌注组脑组织SOD下降,血清SOD先升后降;脑组织NO浓度先降后升,血清NO浓度持续升高;脑组织及血清MDA浓度均先升后降;与缺血再灌注组比,干预组SOD下降幅度小(均P<0·01),NO、MDA浓度明显降低;干预组6h、12h脑组织含水量明显低于缺血再灌注组(均P<0·01)。结论依达拉奉可降低羟自由基水平,对脑缺血再灌注损伤有保护作用。     

Protective effect of ginkgo proanthocyanidins against cerebral ischemia/reperfusion injury associated with its antioxidant effects

Proanthocyanidins have been shown to effectively protect ischemic neurons, but its mechanism remains poorly understood. Ginkgo proan-thocyanidins (20, 40, 80 mg/kg) were intraperitoneally administered 1, 24, 48 and 72 hours before reperfusion. Results showed that ginkgo proanthocyanidins could effectively mitigate neurological disorders, shorten infarct volume, increase superoxide dismutase activity, and de-crease malondialdehyde and nitric oxide contents. Simultaneously, the study on grape seed proanthocyanidins (40 mg/kg) conifrmed that different sources of proanthocyanidins have a similar effect. The neurological outcomes of ginkgo proanthocyanidins were similar to that of nimodipine in the treatment of cerebral ischemia/reperfusion injury. Our results suggest that ginkgo proanthocyanidins can effectively lessen cerebral ischemia/reperfusion injury and protect ischemic brain tissue and these effects are associated with antioxidant properties.     

Effect of nicorandil on infarct volume and marker enzyme activity in mitochondria of rats with cerebral ischemia/ reperfusion injury

BACKGROUND: Recent studies have suggested that mitochondrial ATP-sensitive K channel openers could reduce myocardium infarct size, and protect the function of the mitochondria.OBJECTIVE: To investigate the changes of cerebral infarction volume and the activity of marker enzymes in brain mitochondria of rats given the ATP-sensitive K channel opener, nicorandil, before focal cerebral ischemia/reperfusion (I/R).DESIGN, TIME AND SETTING: Randomized, controlled animal experiment, completed at the Brain Scientific Research Center of the Affiliated Hospital of Qingdao University from July to November 2007.MATERIALS: Sixty healthy male Wistar rats weighing 280-300g. Nicorandil, 5-hydroxydecanoate (5-HD) and cytochrome C were purchased from Sigma in the USA. Standard malondialdehyde (MDA) and protein were purchased from Nanjing Jiancheng Biotechnology Institute.METHODS: Sixty rats were randomly divided into a sham operation group, a middle cerebral artery occlusion (MCAO) group, a nicorandil group and a nicorandil 5-HD group. MCAO for 2 hours was performed in the MCAO group, nicorandil group and nicorandil 5-HD group. A total of 5mL saline were given to the MCAO group before MCAO. The nicorandil group was injected with the ATP-sensitive K channel opener nicorandil 10mg/kg intraperitoneally 30 minutes before MCAO. The nicorandil 5-HD group was injected with 5-HD 10mg/kg intravenously 15 minutes before the same treatment as the nicorandil group.MAIN OUTCOME MEASURES: Infarct volume by total brain slice calculation, activities of succinate dehydrogenase (SDH) and cytochrome oxidase (CO), and content of MDA were observed at 22 hours of reperfusion after 2 hours MCAO.RESULTS: Sixty rats were included in the final analysis, without any loss. (1) Infarct volume: compared with the MCAO group and nicorandil 5-HD group, the percentage of infarct volume was significantly decreased in the nicorandil group (P<0.01). (2) The content of MDA, expression of SDH and CO in brain: the expressions of SDH and CO in the sham operation group were significantly lower than those in the MCAO, nicorandil and nicorandil 5-HD groups (P<0.01). The expressions of SDH and CO in the nicorandil group were significantly higher than those in the MCAO and nicorandil 5-HD groups (P<0.05). The content of MDA in the brain of the nicorandil group was significantly lower than those in the MCAO and nicorandil 5-HD groups (P<0.01).CONCLUSION: Nicorandil can significantly reduce the infarct volume in a rat MCAO model, increase the activity of the mitochondria and protect against cerebral I/R injury.     

颈交感干离断对局灶性脑缺血大鼠生存率影响的实验研究

目的研究颈交感干离断(transection of cervical sympathetic trunk,TCST)对局灶性脑缺血大鼠生存率的影响,为临床应用星状神经节阻滞疗法降低缺血性脑血管病死亡率提供实验依据。方法采用改良的ZeaLonga方法制备大鼠大脑中动脉栓塞(middle cerebral artery occlusion,MCAO)模型。雄性Wistar大鼠236只,随机分为:大脑中动脉栓塞模型组(M组)和颈交感干离断组(T组),颈交感干离断组在造成MCAO模型的同时行TC-ST。两组动物均按栓塞时间又分为6h、24h、48h、72h4个时间点,计算并比较M组与T组在上述各时间点生存率的区别。结果T组在24h、48h及72h平均生存率明显高于M组(P<0.05);T组与M组比较6h生存率无明显差别(P>0.05)。结论颈交感干离断能够有效的提高局灶性脑缺血大鼠的生存率并可能有治疗作用。     

局灶性脑缺血/再灌注损伤后大鼠脑组织tPA表达变化与细胞凋亡研究

目的　探讨大鼠脑缺血 /再灌注后脑组织内组织型纤溶酶原激活物 (t PA)表达变化及与细胞凋亡的关系和意义。方法　采用大鼠局灶性脑缺血 /再灌注模型 ,应用免疫组化染色及原位杂交技术检测脑组织 t PA表达变化 ,TU NEL 染色观察神经元的凋亡及其发生规律。结果　 t PA蛋白及 m RNA在缺血再灌注早期即开始表达 ,主要见于皮质损伤区周围及海马区 ,阳性着色的神经元表达明显 ,血管表达较弱。再灌注 4 8h神经元表达明显增强 ,缺血灶及其周边的微血管内皮表达也明显增强。再灌注 72 h表达有所下降。凋亡细胞主要出现于大脑皮质及尾壳核病变中心区的周围 ,再灌注 4 8～ 72 h达高峰。结论　脑缺血 /再灌注损伤可诱导神经元及血管内皮细胞 t PA表达增加 ,t PA可能通过促进细胞凋亡而介导再灌注损伤。     

Neuroprotective effects of rutaecarpine on cerebral ischemia reperfusion injury**

Rutaecarpine,an active component of the traditional Chinese medicine Tetradium ruticarpum,has been shown to improve myocardial ischemia reperfusion injury.Because both cardiovascular and cerebrovascular diseases are forms of ischemic vascular disease,they are closely related.We hypothesized that rutaecarpine also has neuroprotective effects on cerebral ischemia reperfusion injury.A cerebral ischemia reperfusion model was established after 84,252 and 504 μg/kg rutaecarpine were given to mice via intraperitoneal injection,daily for 7 days.Results of the step through test,2,3,5-triphenyl tetrazolium chloride dyeing and oxidative stress indicators showed that rutaecarpine could improve learning and memory ability,neurological symptoms and reduce infarction volume and cerebral water content in mice with cerebral ischemia reperfusion injury.Rutaecarpine could significantly decrease the malondialdehyde content and increase the activities of superoxide dismutase and glutathione peroxidase in mouse brain.Therefore,rutaecarpine could improve neurological function following injury induced by cerebral ischemia reperfusion,and the mechanism of this improvement may be associated with oxidative stress.These results verify that rutaecarpine has neuroprotective effects on cerebral ischemia reperfusion in mice.