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OBJECTIVE@#To improve the classical 4-vessel occlusion (4VO) model established by Pulsinelli and Brierley.@*METHODS@#Thirty-two male SD rats were randomized into sham operation group, I4VO-Con10 group, I4VO-Int10 group and I4VO-Int15 group. The sham surgery group underwent exposure of the bilateral vertebral arteries and carotid arteries without occlusion to block blood flow. The I4VO-Con10 group experienced continuous ischemia by occluding the bilateral vertebral arteries and carotid arteries for 10 minutes followed by reperfusion for 24 hours. The I4VO-Int10 and I4VO-Int15 groups were subjected to intermittent ischemia. The I4VO- Int10 group underwent 5 minutes of ischemia, followed by 5 minutes of reperfusion and another 5 minutes of ischemia, and then reperfusion for 24 hours. The I4VO-Int15 group experienced 5 minutes of ischemia followed by two cycles of 5 minutes of reperfusion and 5 minutes of ischemia, and then reperfusion for 24 hours. The regional cerebral blood flow (rCBF) was monitored with laser Doppler scanning, and survival of the rats was observed. HE staining was used to observe hippocampal pathologies to determine the optimal method for modeling. Another 48 rats were randomized into 6 groups, including a sham operation group and 5 model groups established using the optimal method. The 5 I4VO model groups were further divided based on the reperfusion time points (1, 3, 7, 14, and 28 days) into I4VO-D1, I4VO-D3, I4VO-D7, I4VO- D14, and I4VO- D28 groups. Body weight changes and survival of the rats were recorded. HE staining was used to observe morphological changes in the hippocampal, retinal and optic tract tissues. The Y-maze test and light/dark box test were used to evaluate cognitive and visual functions of the rats in I4VO-D28 group.@*RESULTS@#Occlusion for 5 min for 3 times at the interval of 5 min was the optimal method for 4VO modeling. In the latter 48 rats, the body weight was significantly lower than that of the sham-operated rats at 1, 3, 7, 14 and 28 days after modeling without significant difference in survival rate among the groups. The rats with intermittent vessel occlusion exhibited progressive deterioration of hippocampal neuronal injury and neuronal loss. Cognitive impairment was observed in the rats in I4VO-D28 group, but no obvious ischemic injury of the retina or the optic tract was detected.@*CONCLUSION@#The improved 4VO model can successfully mimic the main pathological processes of global cerebral ischemia-reperfusion injury without causing visual impairment in rats.
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Ratas , Masculino , Animales , Ratas Sprague-Dawley , Isquemia Encefálica , Infarto Cerebral , Daño por Reperfusión , Peso CorporalRESUMEN
Retinal ischemia is the common pathologic process in many ophthalmic diseases, including ischemic optic neuropathy, retinal artery and vein occlusion, carotid artery obstructive disease, retinopathy of prematurity, chronic diabetic retinopathy and glaucoma. It is very important to establish animal models to investigate pathology mechanism and explore the treatment of retinal ischemia disease. At present, the commonly used methods for establishing retinal ischemia animal models include increasing intraocular pressure, ligating of blood vessels, suture method, photochemical method, and drug injection etc. This article summarizes the methods to establish the animal models and analyzes the indication for each animal model. It is expected that the method of establishing a retinal ischemic animal model will be helpful to the experimental design of follow-up retinal ischemia studies.
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Objective To investigate the effect of cortical 8-opioid receptor (DOR) on oxygen-glucose deprivation-induced (OGD-induced) neuronal injury. Methods Primary cultured cortical neurons incubated with selective DOR agonist (TAN-67) and antagonist (naltrindole) or PKC inhibitor (chelerythrine, CHE) were exposed to OGD. Lactate dehydrogenase (LDH) release was detected after 24 h reperfusion. The expression levels of DOR were measured by Western blot. Results Compared with OGD group, TAN-67 significantly decreased OGD-indueed LDH release, and increased the expression levels of DOR, while nahrindole aggravated neuronal injury and decreased the DOR protein expression. CHE could abolish the LDH down-regulation induced by TAN-67 plus OGD (P< 0.05, compared with TAN-67 treated group). Conclusions DOR activation protects neurons against OGD injury. PKC might take part in the neuroprotection pathways of DOR.
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OBJECTIVE: To explore the effect of delta-opioid receptor (DOR) in electroacupuncture (EA) protecting the brain against acute ischemic injury. METHODS: Fifty-one rats were randomly divided into sham ischemia group, ischemia group, sham EA group, EA group, and EA+DOR antagonist (naltrindole) group. Transient focal cerebral ischemia (1 hour) was induced in rat brain by middle cerebral artery occlusion (MCAO) method. EA was applied on Shuigou (GV 26) and Neiguan (PC 6) for 30 min, starting immediately after the onset of reperfusion. Neurological deficit scores and volume of cerebral infarction were detected after 24-hour reperfusion. Other 12 rats were randomly divided into sham ischemia group, ischemia group, EA group and EA + naltrindole group. DOR protein expressions were assessed by Western blotting after 24-hour reperfusion. RESULTS: In comparison with the ischemia group and sham EA group, EA significantly reduced ischemic infarction and neurological deficits (P0.05). When naltrindole was combined with EA, the naltrindole completely abolished the EA-induced protection in ischemic infarction and neurological deficits, and also arrested the expression of DOR. CONCLUSION: EA can up-regulate DOR expression and protect the brain from ischemia-reperfusion injury.
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BACKGROUND: Ramulus Uncariae et Uncus can be used to treat many diseases of cardiovesculer and neurosystem by calming and protecting endothelium and neuron.OBJECTIVE: To study the effects of drinking water extracts of Ramulus Uncariae et Uncus on body mass, food intake, energy intakes, serum glucose, insulin, total antioxidative ability of high-fat-fed rats.DESIGN: A completely randomized and controlled experiment.SETTING: Institute of Physiology, Foundational Medical College of Lanzhou University.MATERIALS: The experiment which is Gansu Province Key Labor of Pre-clinical Research for Chinese Herbs & New Drugs was carried out at the Physiological Laboratory of Institute of Foundational Medical College of Lanzhou University from March 2003 to May 2003. Twenty-seven healthy male SD rats were randomly divided into the following three groups (9 rats each group): namely, the normal control group, the high-fat-fed group and the Ramulus Uncariae et Uncus group.METHODS: [1] The rats of control group were fed with referenced diets(Protein, fat and carbohydrate was made up fore18.2%, 4.5%, 55.2% respectively), while the rats of high-fat-fed and the Ramulus Uncariae et Uncus group were fed with high-fat diets in which protein, fat and carbohydrate accounted for 23.7%, 21.6%, 39.0% respectively. [2]The rats in control and high-fat group could drink water freely every day while the rats in Ramulus Uncariae et Uncus group drank freely one percent water extract of Ramulus Uncariae et Uncus at the first day of the experiment, later the concentration of Ramulus Uncariae et Uncus increased gradually to six percent at the sixth day, which lasted until the end of the experiment. [3]Food intake was monitored daily, and body mass weekly at set time, the energy intake was calculated on basis of food intake. We calculated the Lee's Index [(body mass)1/3 (g) × 103 / body length (cm)]. [4] At the end of the seventh week, all rats were fasted for twelve hours to collect blood for the measure of some serum items. The serum levels of glucose were determined with hexokinase. The levels of insulin was measured by Radioimmunology methods. Malondiadehyde was measured by thiobarbituricbased colorimetric assay. Total antioxidative ability and free fatty acid were evaluated by colorimetric assay. [5] The difference of quantity data among the tree groups were statistically analyzed by F analysis, while the difference between two groups was analyzed by LSD methods. The main indexes of the experiment were body mass, food intake, energy intake, serum glucose after fasting, insulin, free fatty acid, malondialdehyde and total antioxidative ability respectively.RESULTS: Twenty-seven rats date was analyzed and nine rats in every group. [1] Body mass: Compared with the high-fat-fed group, body mass in rats of the control group and the Ramulus Uncariae et Uncus group were less from the end of the third week to the end of the experiment (P ＜ 0.05-0.01).As compared between the Ramulus Uncariae et Uncus group and the control group, there was no significant difference from the first week to the sixth week (P ＞ 0.05), while the body mass of the former group was bigger than that of the latter at the end of the seventh week (P ＜ 0.01). [2] Lee's Index of the rats in high-fat-fed group was significantly higher than those of the rats in the control and Ramulus Uncariae et Uncus group (P ＜ 0.01).[3] Food intake: From the first week, compared with the control group, the food intake of rats in Ramulus Uncariae et Uncus group was less (P ＜ 0.01)and lower than that in high-fat-fed group at the end of the third, fifth, sixth and seventh week, too (P ＜ 0.05-0.01). [4] Energy intake: As the food was high-fat, the Energy intake of rats in the Ramulus Uncariae et Uncus group was higher than that of the control group at the end of the first, second and forth week (P ＜ 0.05-0.01), while less than that of the high-fat-fed group at the end of the third, fifth, sixth and seventh week (P ＜ 0.01). [5] The serum glucose: There was no statistical significance among the three groups. [6]The level of serum insulin and malondiadehyde of the rats in high-fat-fed group were higher than that of the control group and the Ramulus Uncariae et Uncus (P ＜ 0.01). [7] The level of free fatly acid of rats in high-fat-fed group was higher than that of the control group (P ＜ 0.05), while there wasno statistical difference compared with the Ramulus Uncariae et Uncus group. [8] The level of total antioxidative of the rats in high-fat group was lower than that of the Ramulus Uncariae et Uncus group (P ＜ 0.01).CONCLUSION: [1] Drinking water extracts of Ramulus Uncariae et Uncus could inhibit the weight gain and food intake, [2] reduce level of free radical and insulin of serum, which could be caused by the dec lining of free fatty acid. [3] In the same time, increase the total antioxidative ability of the obese rats caused by high-fat diets.