Neuroprotective effect of angiotensin Ⅱ type 2 receptor during cerebral ischemia/reperfusion

Angiotensin Ⅱ type 2 receptor(AT2R) activation has been shown to protect against stroke,but its precise mechanism remains poorly understood.We investigated whether the protective effect of AT2 R against ischemia/reperfusion injury is mediated by the suppression of immune and inflammatory responses.Rat models of middle cerebral artery occlusion were intraperitoneally injected with physiological saline,the AT2 R agonist CGP42112(1 mg/kg per day) or antagonist PD123319(1 mg/kg per day).In the CGP42112 group,AT2 R expression increased,the infarct area decreased,interleukin-1β and tumor necrosis factor-α expression decreased,and interleukin-10 expression increased compared with the saline group.Antagonisin AT2 R using PD123319 produced the opposite effects.These results indicate that AT2 R activation suppresses immune and inflammatory responses,and protects against cerebral ischemia/reperfusion injury.     

Scavenger receptor class-A has a central role in cerebral ischemia–reperfusion injury

The innate immune response is involved in the pathophysiology of cerebral ischemia–reperfusion (I/R) injury. Recent evidence suggests that scavenger receptors have a role in the induction of innate immunity. In this study, we examined the role of scavenger receptor A (SR-A) in focal cerebral I/R injury. Both SR-A^−/− mice (n=10) and age-matched wild-type (WT) mice (n=9) were subjected to focal cerebral ischemia (60 minutes), followed by reperfusion (for 24 hours). Infarct size was determined by TTC (triphenyltetrazolium chloride) staining. The morphology of neurons in the brain sections was examined by Nissl''s staining. Activation of intracellular signaling was analyzed by western blot. Cerebral infarct size in SR-A^−/− mice was significantly reduced by 63.9% compared with WT mice after cerebral I/R. In SR-A^−/− mice, there was less neuronal damage in the hippocampus compared with WT mice. Levels of FasL, Fas, FADD, caspase-3 activity, and terminal deoynucleotidyl transferase-mediated 2′-deoxyuridine 5′-triphosphate-biotin nick end labeling-positive apoptotic cells were significantly increased in WT mice after cerebral I/R, but not in SR-A^−/− mice. Cerebral I/R increased nuclear factor-κB activation in WT mice, but not in SR-A^−/− mice. These data suggest that SR-A has a central role in cerebral I/R injury and that suppression of SR-A may be a useful approach for ameliorating brain injury in stroke patients.     

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.     

Neuroprotective effect of human placental extract on hypoxic–ischemic brain injury in neonatal rats

We investigated the neuroprotective effects of human placental extracts (HPE) and the effects of HPE on recovery of cognitive and behavioral function on hypoxic–ischemic brain injury in the newborn rat. The right common carotid arteries of 7-day-old rats were coagulated, and rats were then exposed to 8% oxygen. Immediately before and again at three times after the hypoxia–ischemia (pre-treatment group), and immediately after and three times again after hypoxia–ischemia (post-treatment group), the rats were intraperitoneally injected with HPE (0.1, 0.25, or 0.5 mL/10 g/dose). No-treatment rats received saline only. On postnatal day 12, brains were removed and gross morphological damage was evaluated. To quantify the severity of brain injury, bilateral cross-sectional areas of the anterior commissural and posterior hippocampal levels were analyzed with NIH Image. Assessments of the open field activity levels at 2, 4, 6 and 8 week and, the Morris water maze test at 8 weeks after hypoxia–ischemia were carried out according to standard methods. HPE pre-treatment decreased the incidence of liquefactive cerebral infarction, at an optimally neuroprotective dose of 0.5 mL/10 g/dose (P < 0.05). In the Morris water maze test, the group injected with HPE at 0.5 mL/10 g/dose concentration showed shorter escape latencies than the no-treatment group (P < 0.05). These findings support a protective effect of the HPE treatment on neuronal integrity and cognitive function following hypoxic–ischemic brain injury. Injected at an appropriate dose prior to exposure, HPE may significantly reduce or prevent hypoxic–ischemic injury in the immature brain.     

Dose-dependent effects of procyanidin on nerve growth factor expression following cerebral ischemia/ reperfusion injury in rats★

BACKGROUND： Recently, grape seed procyanidin （GSP） has been shown to be exhibit antioxidant effects, effectively reducing ischemia/reperfusion injury and inhibiting brain cell apoptosis. OBJECTIVE： To study the effects of GSP on nerve growth factor （NGF） expression and neurological function following cerebral ischemia/reperfusion injury in rats. DESIGN： Randomized controlled study based on SD rats. SETTING： Weifang Municipal People＇s Hospital. MATERIALS： Forty-eight healthy adult SD rats weighing 280-330 g and irrespective of gender were provided by the Experimental Animal Center of Shandong University. GSP derived from grape seed was a new high-effective antioxidant provided by Tianjin Jianfeng Natural Product Researching Company （batch number： 20060107）. Rabbit-anti-rat NGF monoclonal antibody was provided by Beijing Zhongshan Biotechnology Co., Ltd., and SABC immunohistochemical staining kit by Wuhan Boster Bioengineering Co., Ltd. METHODS： The present study was performed in the Functional Laboratory of Weifang Medical College from April 2006 to January 2007. Forty-eight SD rats were randomly divided into the sham operation group, ischemia/reperfusion group, high-dose GSP （40 mg/kg） group, or low-dose GSP （10 mg/kg） group （n = 12 per group）. Ischemia/reperfusion injury was established using the threading embolism method of the middle cerebral artery. Rats in the ischemia/reperfusion model group were given saline injection （2 mL/kg i.p.） once daily for seven days pre-ischemia/reperfusion, and once more at 15 minutes before reperfusion. Rats in the high-dose and low-dose GSP groups were injected with GSP （20 or 5 mg/mL i.p., respectively, 2 mL/kg） with the same regime as the ischemia/reperfusion model group. The surgical procedures in the sham operation group were as the same as those in the ischemia/reperfusion model group, but the thread was approximately 10 mm long, thus, the middle cerebral artery was not blocked. MAIN OUTCOME MEASURES： NGF expression in the     

Neuroprotective effect of estrogen after chronic spinal cord injury in ovariectomized rats

BACKGROUND: At present, there is still lack of effective drugs for chronic spinal cord injury, whereas it is found recently that estrogen has a neuroprotective effect on brain and spinal cord injuries. OBJECTIVE: To observe the effect of estrogen on the apoptosis of nerve cells after gradual chronic spinal cord injury in ovariectomized rats. DESIGN: A randomized controlled animal trial. SETTING: Institute of Orthopaedics, the Second Hospital of Lanzhou University. MATERIALS: Sixty-five female Wistar rats of common degree, weighing 220–250 g, were provided by the experimental animal center of Lanzhou University. The rats were randomly divided into sham-operated group (n =5), estrogen-treated group (n =30) and saline control group (n =30), and the latter two groups were observed at 1, 3, 7, 14, 28 and 60 days respectively, and 5 rats for each time point. METHODS: All the rats were treated with bilateral oophorectomy 2 weeks before the experiment. T10 vertebral lamina was revolved into using plastic screw. The spinal canal impingement was not induced initially. After that, the original incision was opened to expose the screw every 7–10 days. MAIN OUTCOME MEASURES: The apoptosis and Caspase-3 positive cells in the damaged spinal cord were detected using terminal deoxynucleotidal transferase-mediated dUTP-biotin nick end labeling (TUNEL) method and Caspase-3 immunohistochemical staining at 1, 3, 7, 14, 28 and 60 days after chronic spinal cord injury respectively. RESULTS: Totally 65 rats were used, and the deleted ones during the experiment were supplemented by others. Changes of Caspase-3 expression after spinal cord injury: In the sham-operated group, only a small amount of Caspase-3 proteins were observed in the rat spinal cord, mainly located in motor neurons of spinal cord anterior horn. In the estrogen-treated group and saline control group, positive cells expressed occasionally at 1 day postoperatively, began to increase obviously at 7 days after injury, strongly expressed at 14 and 28 days, but decreased at 60 days, mainly located in the neurons of spinal cord gray matter anterior horn, and they expressed fewer in the motor neurons and white matter of ventral horn, and there were obvious differences between the estrogen-treated group and saline control group at 7, 14, 28 and 60 days (P < 0.05). CONCLUSION: Estrogen can reduce the apoptosis of nerve cells and promote the recovery of neurological function following gradual chronic spinal cord injury.     

Neuroprotective effect of G14-humanin on global cerebral ischemia/reperfusion by activation of SOCS3 – STAT3 – MCL–1 signal transduction pathway in rats

Objective: Humanin (HN) has been identified to suppress neuron death. Gly¹⁴-HN (HNG), as a variant of HN, can decrease infarct volume after ischemia/reperfusion (I/R) injury. This study aimed to investigate the neuroprotective mechanism of HNG on global cerebral I/R (GI) in rats.

Methods: Rats were randomly divided into 13 groups: Sham group, GI groups and HNG groups. Both GI group and HNG groups included six time points (1, 3, 6, 12, 24, and 72 h). At 24 h after reperfusion, Nissl staining was used to observe positive neurons, and p-STAT3, MCL-1, SOCS3, Bax and Caspase-3 in different groups were detected by immunohistochemistry. qRT-PCR and western blot were used to evaluate the expression of STAT3, p-STAT3, MCL–1, and SOCS3.

Results: The immunohistochemistry also showed a significant increase in Bax (0.29 ± 0.007 vs. 0.22 ± 0.007, P < 0.01) and Caspase-3 (0.24 ± 0.02 vs. 0.18 ± 0.006, P < 0.01) in GI group compared with Sham group, while Bax (0.26 ± 0.01 vs. 0.29 ± 0.008, P < 0.01) and Caspase-3 (0.20 ± 0.008 vs. 0.24 ± 0.02, P < 0.01) were significantly decreased by HNG-treatment compared with GI group. Along with immunohistochemistry, western blot and qRT-PCR indicated that the protein and mRNA levels of STAT3, MCL-1, and SOCS3 were up-regulated after administration of HNG at six time points after global cerebral I/R in rat.

Conclusion: HNG might exert neuroprotective effects through alleviating apoptosis and activating of SOCS3 – STAT3 – MCL-1 signal transduction pathway.

Highlights

(1) Cerebral ischemia led to neuronal loss in hippocampal CA1 region of rats.

(2) HNG had neuroprotective effects on ischemia/reperfusion rats.

(3) The protective effect of HNG might be related to the SOCS3 – STAT3 – MCL-1 pathway.

     

High frequency electrical field-ultrashort wave therapy for treatment of cerebral ischemia/reperfusion injury in rats☆ Histopathological evaluation

BACKGROUND: Ultrashortwave (USW) therapy may be a new method for treatment of ischemic cerebrovascular diseases. It is necessary to study its treatment time window. OBJECTIVE: To observe the effect of USW on reperfusion injury after occlusion of the middle cerebral artery (MCAO) in rats and discuss its acting mechanisms and best occasion. DESIGN: Randomized controlled observation, animal experiment. SETTING: Laboratory of Department of Rehabilitation Medicine, First Hospital Affiliated to China Medical University. MATERIALS: Sixty-six healthy Wistar rats of either gender and of clean grade, aged 18–20 weeks, weighing from 250 to 300 g, were provided by the Experimental Animal Center of China Medical University. An USW device (Shanghai Electrical Device Company) with the frequency of 40.68 MHz and the maximum output power of 40 W, and the first channel power controlled at about 11 W was used in this study. Output power was determined by photometry. METHODS: Sixty-six rats were randomly divided into 3 groups: Sham-operation group (n =6): The suture was inserted only 1.0 depth during operation, which did not cause MACO; Model group (n =12): The USW treatment procedure was performed with the power off on the model rats; USW treatment group (n =48): The 48 rats were randomly divided into modeling 0, 6, 12 and 18 hours 4 subgroups. USW therapy without heat was used on the head of rats for 10 minutes at each time point. Twelve rats in USW treatment group were decapitated following treatment at each time point, and then their brain tissues were harvested. The rat brain tissues in other groups were harvested by decapitation at 24 hours after modeling. When the rats were awake, the neurologic deficit was scored by Zea-Longa five-point scale (a score of 0 indicated no neurologic deficit, a score of 1 indicated failure to extend left paw fully, a score of 2 indicated circling to the left, and a score of 3 indicated falling to the left, and rats with a score of 4 did not walk spontaneously and has a depressed level of consciousness.) Rats which still survived at 24 hours and was scored 1 and 2 on the neurologic scoring were involved in the analysis. ① Determination of cerebral water content: Cerebral water contents of healthy and injured hemisphere were determined by wet/dry weighing method. Cerebral water content (100%) =(1–dry/wet weight)×100%.②Infarction volume: The brain tissue was sliced into 2 mm sections and each section was stained with 20 g/L 2,3,5-triphenyltetrazolium chloride (TTC) by TTC staining technique for 30 minutes in a water bath at 37 ℃.Then, the section was fixed in 100 g/L formaldehyde for 10 minutes .The infarction volume was analyzed by using an imaging analyzer.③ Preparation of light microscopic sample: The rat brain tissue fixed by 100 g/L neutral formaldehyde and stained with TTC, were gradiently dehydrated with alcoholic, embedded with paraffin, sliced and stained by HE, finally, the sections were observed under the light microscope. MAIN OUTCOME MEASURES: Cerebral water content, cerebral infarction volume and cerebral histomorphology of rats in each group. RESULTS: Sixty-six rats were involved in the final analysis. ①Cerebral water content: There were no significant differences of cerebral water content in healthy hemisphere among groups (P > 0.05). Cerebral water content of injured hemisphere in the model group and at modeling 0, 6, 12 and 18 hours in the USW treatment group was (81.50±0.74) %, (81.02±0.83) %, (79.78±0.70) %, (79.74±0.84) %, (79.39±1.06) %, respectively, which was significantly higher than that in the sham-operation group [(78.09±0.52) %, P < 0.05]. At modeling 0, 6 and 12 hours, the cerebral water content in the injured hemisphere in the USW treatment group was significantly lower than that in the model group, respectively (P < 0.05). It indicated that USW treatment given at 6, 12 and 18 hours after ischemia/reperfusion can lessen brain edema. ② Cerebral infarction volume: At modeling 18 hours, cerebral infarction volume in the injured hemisphere of USW treatment group was smaller than that in the model group [（191.62±121.45），（362.03±142.01）mm3，t =2.23，P < 0.05]. ③ Cerebral histomorphological observation: No swelling was found in the brain tissue section of rats in the sham-operation group. In the model group, the size of infarction hemisphere was obviously increased, gyrus became flattened, cortical sulci was shallow, the color at infarct focus obviously became light, and the tissue was fragile and brittle. In the sham-operation group, it was found under the microscope that mesenchyma was highly swelled, neuronal peripheral interspace was obviously broadened, neurons presented triangle, nucleoli were reduced, condensed even disappeared, and neutrophils in the vascular cavity were obviously increased. In the USW treatment group, pathological injury was not obviously lessened at 0 hour, moderate or mild edema could be found in the injured hemisphere of USW treatment group at modeling 6,12 and 18 hours, and at this time, neutrophils in vascular cavity were increased slightly, and pathological injuries were lessened. CONCLUSION: USW may play a protective effect on cerebral ischemia/reperfusion injury by decreasing brain edema and/or cerebral infarction volume. The treatment action of USW may start at 6 hours after reperfusion, and the best occasion of application may be at 18 hours after reperfusion.     

Batroxobin plus hypothermia for protection of cerebral ischemia/reperfusion injury models in gerbils

INTRODUCTION Batroxobin, a new kind of agent to inhibit thrombus and meliorate mi- crocirculation, is rapid to take effect with good results, it can decompose fibrinogen and prevent the formation of thrombus[1]. The protective ef- fects ofdeep hypothermia…     

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…     

bcl-xl over-expression in transgenic mice reduces cerebral ischemia/reperfusion injury*☆

BACKGROUND： Basal cell lymphoma-extra large （bcl-xl） can inhibit neuronal apoptosis by stabilizing the mitochondrial membrane and suppressing cytochrome C release into the cytoplasm. OBJECTIVE： This study aimed to further investigate the cascade reaction pathway of cellular apoptosis. We established an ischemia/repcrfusion model by middle cerebral artery occlusion （MCAO） in transgenic and wild-type mice, and observed changes in the number and distribution of apoptotic neural cells, differences in cerebral infarct volume, in neurological function score, and in cytochrome C expression in the ischemic cerebral cortex, at different time points, DESIGN AND SETTING： The present gene engineering and cell biology experiment was performed at the Laboratory of Biology, Hubei Academy of Agricultural Sciences and at the Laboratory of Immunology, Tongji Medical College, Huazhong University of Science and Technology. MATERIALS： Male bcl-xl over-expression Kunming mice aged 8 weeks and age-matched male wild-type mice were used for this study. Terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling （TUNEL） kits were purchased from Boliman, France. Cytochrome C antibody and Bcl-x immunohistochemical kit were purchased from PharMingen, USA and Santa Cruz Biotechnology, USA, respectively. METHODS： Following MCAO and reperfusion, apoptosis in the ischemic cerebral cortex was detected by the TUNEL assay. Prior to MCAO and 3 hours after reperfusion, the Bcl-xl protein level in the ischemic cerebral cortex was measured by immunohistochemistry. At 3, 6, 12 and 24 hours after reperfusion, the level of cytochrome C in the ischemic cerebral cortex was examined by western blot analysis. Subsequent to MCAO, cerebral infarct volume measurement and neurological examination were performed. MAIN OUTCOME MEASURES： Neural cell apoptosis and cytochrome C expression in the ischemic cerebral cortex; cerebral infarct volume and neurological function score. RESULTS： Twenty-four hours after reperfusion, cerebral inf     

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     

Bioinformatic analysis to explore key genes associated with brain ischemia–reperfusion injury in rats

Abstract

Objectives: Ischemia–reperfusion (I/R) injury can aggravate the dysfunction and structural damage of tissues and organs. This study aimed at investigating the pathogenesis of I/R injury.

Methods: GSE82146 was extracted from Gene Expression Omnibus database, which included 12 nonischemic control (NIC) hippocampal tissues and 15 complete global brain ischemia (CGBI)–reperfusion hippocampal tissues. After processing the original data using the affy package, the differentially expressed genes (DEGs) between CGBI and NIC samples were analysed by the limma package. An enrichment analysis for the DEGs was implemented based on the MATHT online tool. Using Cytoscape software, a protein–protein interaction (PPI) network was built and significant network modules were obtained. Finally, miRNA-gene pairs were predicted using the miRWalk2.0 tool, and the miRNA-gene regulatory network was built using the Cytoscape software.

Results: Overall, 322 DEGs (279 upregulated and 43 downregulated) were present in the CGBI samples. In PPI network, JUN, STAT3, ATF3, VEGFA and ATF4 had higher degrees. Four significant modules (modules a, b, c and d) were obtained from PPI network. Enrichment analysis suggested that FGF2 in module d was involved in MAPK signalling pathway. In the miRNA-gene regulatory network, rno-miR-125a-5p and rno-miR-125b-5p were among the top 10 miRNAs.

Conclusion: JUN, STAT3, ATF3, VEGFA, ATF4, FGF2, rno-miR-125a-5p and rno-miR-125b-5p might affect the development and progression of I/R 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 280-320 g, 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 10 mm, 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     

Neuroprotective effect of high-dose hyperbaric oxygenation on rats with acute cerebral infarction in super-early stage

BACKGROUND: Previously, only single short-time low-dose hyperbaric oxygenation (HBO) protocol was administrated to treat acute ischemic stroke in early stage and the conflicting results were obtained. There are few studies to report the outcome of administering long-time (can cover all the natural pathologic progression period) high-dose HBO to treat the disease. OBJECTIVE: To evaluate the therapeutic effect between two kinds of high-dose hyperbaric oxygenation on super-early stage of acute permanent middle cerebral artery occlusion (MCAO) in rats. DESIGN: A randomized controlled experimental study. SETTING: Beijing Tiantan Hospital, Capital Medical University; Beijing Research Institute of Neurosurgery. MATERIALS: Seventy-four male SD rats, aged 2.5 months old, weighing （280±20）g, were provided by the Animal Institute, Chinese Academy of Medical Sciences. Hyperbaric oxygenation device was hyperbaric air cabin in which there was a self-made pure oxygen animal experimental cabin (made in China). METHODS: This experiment was carried out in the municipal laboratory of Beijing Tiantan Hospital affiliated to Capital Medical University and Beijing Research Institute of Neurosurgery. ① Experimental intervention: All the rats were developed into models of permanent MCAO by suture embolism. Then, they were randomly divided into two HBO groups (9 hours and 18 hours) and control group, with 24 rats in each as well as 3-hour ultrastructure control group, with 2 rats. After being modeled for 3 hours, rats in the two HBO groups stayed in the hyperbaric cabin for 9 hours and 18 hours, separately. Rats in the 9-hour HBO group inhaled pure oxygen at hours 1, 3, 5, 7 and 9, and hyperbaric air at hours 2, 4, 6 and 8. Rats in the 18-hour HBO group inhaled pure oxygen at hours 1, 3, 5, 7, 9, 11, 13, 15 and 17, and hyperbaric air at hours 2, 4, 6, 8, 10 12, 14, 16 and 18. After being created into models, rats in the control group and 3-hour ultrastructure control group breathed room air. ② Experimental evaluation: Neurologic functions of rat models in the 9-hour and 18-hour HBO groups as well as control group were scored by Bederson and Garica two neurological grading systems at hours 14 and 28 and on day 5; Infarct volume of rat models in the two HBO groups and control group was measured at hour 24 and on day 5 with NIH image processing software Image J; The pathological changes of brain tissue in the brain infarct region and its opposite region of rat models in the two HBO groups and 3-hour ultrastructure control group were observed with a Philips EM 208S transmission electron microscope. MAIN OUTCOME MEASURES: ① Neurobehavioral outcome. ② Rat brain infarct volume. ③ Ultrastructure of brain tissue in the ischemic penumbra of infarct models at the different time points RESULTS: ① Neurobehavioral outcome: After treatment, Garica score in the 9-hour and 18-hour HBO groups was significantly higher than that in the control group (P < 0.01). Bederson score on day 5 after modeling in the 9-hour and 18-hour HBO groups was significantly lower than that in the control group (P < 0.01). ② Cerebral infarct volume: Cerebral infarct volume in the 9-hour and 18-hour HBO groups was significantly smaller than that in the control group at hour 24 and on day 5 after modeling (P < 0.01). In the 18-hour HBO group, infarct volume on day 5 after modeling was significantly larger than that at hour 24 after modeling (P < 0.05). ③In the 3-hour ultrastructure control group, astrocyte edema and neuron damage around the capillary in the infarct cerebral tissue significantly relieved in the rats which were subjected to HBO. CONCLUSION: High dose of HBO is highly efficient in reducing infarct volume and improving neurobehavioral outcome of rats with acute cerebral infarction, and also has an important role in inhibiting the pathological progression of ischemic brain tissue after cerebral infarction.     

Neuroprotective effect of (–)-epigallocatechin-3-gallate in rats when administered pre- or post-traumatic brain injury

Our previous study indicated that consuming (–)-epigallocatechin gallate (EGCG) before or after traumatic brain injury (TBI) eliminated free radical generation in rats, resulting in inhibition of neuronal degeneration and apoptotic death, and improvement of cognitive impairment. Here we investigated the effects of administering EGCG at various times pre- and post-TBI on cerebral function and morphology. Wistar rats were divided into five groups and were allowed access to (1) normal drinking water, (2) EGCG pre-TBI, (3) EGCG pre- and post-TBI, (4) EGCG post-TBI, and (5) sham-operated group with access to normal drinking water. TBI was induced with a pneumatic controlled injury device at 10 weeks of age. Immunohistochemistry and lipid peroxidation studies revealed that at 1, 3, and 7 days post-TBI, the number of 8-Hydroxy-2′-deoxyguanosine-, 4-Hydroxy-2-nonenal- and single-stranded DNA (ssDNA)-positive cells, and levels of malondialdehyde around the damaged area were significantly decreased in all EGCG treatment groups compared with the water group (P < 0.05). Although there was a significant increase in the number of surviving neurons after TBI in each EGCG treatment group compared with the water group (P < 0.05), significant improvement of cognitive impairment after TBI was only observed in the groups with continuous and post-TBI access to EGCG (P < 0.05). These results indicate that EGCG inhibits free radical-induced neuronal degeneration and apoptotic death around the area damaged by TBI. Importantly, continuous and post-TBI access to EGCG improved cerebral function following TBI. In summary, consumption of green tea may be an effective therapy for TBI patients.     

Changes of cerebral blood flow in rats with acute cerebral ischemia and the effect of nitric oxide donor S-nitroso-N-acetyl-penicillamine

INTRODUCTION In cerebral ischemia, the production of nitric oxide increases, which leads to the increase of cyclic guanosine monophosphate (cGMP) and thus the dilation of the cerebral vessles. cGMP is an important regulatory factor mediating a vasodilatoy…