Oral administration of metal chelator ameliorates motor dysfunction after a small hemorrhage near the internal capsule in rat

Cerebral hemorrhage leads to local production of free iron, radicals, cytokines, etc. To investigate whether a decrease of iron-mediated radical production influences functional recovery after intracerebral hemorrhage (ICH), a modified ICH rat model with a small hemorrhage near the internal capsule (IC) accompanied with relatively severe motor dysfunction was first developed. Then clioquinol (CQ), an iron chelator that reduces hydroxyl radical production, was orally administrated. Injection of different doses of Type IV collagenase (1.4 mul 1-200 U/ml) into the left striatum near the IC in Wistar rats showed that injection of 7.5 U/ml collagenase resulted in a small hemorrhoidal lesion near the IC with relatively severe motor dysfunction (IC model). Retrograde labeling of neurons in the sensory-motor cortex and axons in the corticospinal tract using Fluoro-gold (FG) injection into the spinal cord (C3-C4) showed that few labeled neurons in the sensory-motor cortex were detected in the IC model, FG-labeled axons disappeared, and FG-including ED-1-positive cells appeared within 24 hr in the IC. Assessments of behavior and histologic analysis after oral administration of CQ in the IC model indicated that oral administration of CQ prevented a decrease of FG-labeled neurons, and resulted in better motor-function recovery. CQ inhibited hydrogen peroxide-induced cell toxicity in oligodendrocytes in vitro, but not in neurons. Our data suggests that CQ ameliorated motor dysfunction after a small hemorrhage near the IC by a mechanism that is related to reduction of chain-reactive hydroxyl radical production in oligodendrocytes.     

A change in injured corticospinal tract originating from the premotor cortex to the primary motor cortex in a patient with intracerebral hemorrhage

Many studies have attempted to elucidate the motor recovery mechanism of stroke,but the majority of these studies focus on cerebral infarct and relatively little is known about the motor recovery mechanism of intracerebral hemorrhage.In this study,we report on a patient with intracerebral hemorrhage who displayed a change in injured corticospinal tract originating from the premotor cortex to the primary motor cortex on diffusion tensor imaging.An 86-year-old woman presented with complete paralysis of the right extremities following spontaneous intracerebral hemorrhage in the left frontoparietal cortex.The patient showed motor recovery,to the extent of being able to extend affected fingers against gravity and to walk independently on even ground at 5 months after onset.Diffusion tensor imaging showed that the left corticospinal tract originated from the premotor cortex at 1 month after intracerebral hemorrhage and from the left primary motor cortex and premotor cortex at 5 months after intracerebral hemorrhage.The change of injured corticospinal tract originating from the premotor cortex to the primary motor cortex suggests motor recovery of intracerebral hemorrhage.     

Melatonin reduces traumatic brain injur y-induced oxidative stress in the cerebral cortex and blood of rats

Free radicals induced by traumatic brain injury have deleterious effects on the function and antioxidant vitamin levels of several organ systems including the brain. Melatonin possesses antioxidant effect on the brain by maintaining antioxidant enzyme and vitamin levels. We investigated the effects of melatonin on antioxidant ability in the cerebral cortex and blood of traumatic brain injury rats. Results showed that the cerebral cortex β-carotene, vitamin C, vitamin E, reduced glutathione, and erythrocyte reduced glutathione levels, and plasma vitamin C level were decreased by traumatic brain injury whereas they were increased following melatonin treatment. In conclusion, melatonin seems to have protective effects on traumatic brain injury-induced cerebral cortex and blood toxicity by inhibiting free radical formation and supporting antioxidant vitamin redox system.     

内囊后肢梗死患者皮质脊髓束的重组

Several diffusion tensor-imaging studies have demonstrated motor recovery mechanisms in stroke patients with subcortical infarct,including the corona radiata,pons,and medulla.However,studies of motor recovery mechanisms have not been reported in patients with posterior limb infarcts of the internal capsule.The present study reports on a 77-year-old man with complete paralysis of the left extremities at stroke onset.At 6 months after onset,motor function of the left extremities recovered to a nearly normal state.The 3-week diffusion tensor tractography of the affected(right) hemisphere showed that corticospinal tract discontinued below the posterior limb.In contrast,6-month diffusion tensor tractography revealed that the right corticospinal tract originated from the precentral gyrus and descended along the anterior area of the infarcted posterior limb.Motor function of the affected extremities was reorganized into the anterior area of the posterior limb infarct.     

Protection of Cactus Polysaccharide against H2O2-induced damage in the rat cerebral cortex and hippocampus Differences In time of administration

BACKGROUND: Pharmacological research has shown that cactus polysaccharide (CP) has anti-oxidant, anti-inflammatory, antitumor, anti-aging, and immune-stimulating activities. It may also provide protective effects against oxidative stress injuries in the rat brain.OBJECTIVE: To validate the effects of CP on H2O2-induced oxidative stress injuries in the ratcerebral cortex and hippocampal slices 30 minutes prior to injury, as well as 30 minutes and 2.5 hours after injury.DESIGN: A randomized controlled experiment.SETTINGS: Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology; Department of Pharmacology, College of Medical Science, Yangtze University.MATERIALS: A total of 50 male Sprague Dawley (SD) rats, normal grade and weighing 200-300 g, were provided by the Laboratory Animal Center of Tongji Medical College, Huazhong University of Science and Technology. The protocol was performed in accordance with ethical guidelines for the use and care of ani-mals. Cactus polysaccharide, a dried needle crystal, was extracted from Opuntia milpa alta at the Chemistry and Environment Engineering School of Yangtze University. The following chemicals and instruments were used: 2,3,5-triphenyl tetrazolium chloride (Sigma, St Louis, Missouri, USA); lactate dehydrogenase (LDH), superoxide dismutase (SOD), glutathione (GSH), and total antioxidant competence (T-AOC) assays (Jiancheng-Bioeng Institute, Nanjing); McIllwain tissue chopper (Mickle Laboratory Engineering, USA); and ELISA reader and Magellan software (TECAN, Austria).METHODS: This experiment was performed at the Department of Pharmacology, Medical College of Yangtze University, between March and June 2006. All rats were sacrificed after anesthesia. The cerebral cortex and hippocampus were dissected. Several cerebral cortex and hippocampus slices were selected as controls, while other sections were co-incubated with H2O2 for 30 minutes to induce an oxidative stress injury. The experimental slices were randomly divided into 3 groups: model group, low-dose group, and high-dose group. Slices from the low- and high-dose group were incubated with CP 30 minutes prior to injury, as well as 30 minutes and 2.5 hours after injury. The number of cerebral cortex and hippocampus slices at each time point was greater than 10 and 7, respectively. The control group slices were incubated with artificial cerebro-spinal fluid (aCSF) for 3 hours. The model group slices were incubated with aCSF for 30 minutes, followed by 30 minutes of aCSF with H2O2 incubation to establish the oxidative stress injury model. Thereafter, the slices were re-incubated with aCSF for 2 hours. The slices in the low- and high-dose group were co-incubated with 0.33 mg/L CP or 1.67 mg/L CP, respectively. CP was applied either for 30 minutes prior to the H2O2 treatment, co-incubated with H2O2 for 30 minutes, or applied 2 hours after H2O2 treatment.MAIN OUTCOME MEASURES: Brain slice activity was determined by TTC staining. Biochemical mark-ers, such as LDH, SOD, GSH, and T-AOC, were analyzed in clear supernatant liquid to study the pharma-cological mechanisms.RESULTS: ① Effects of CP on H2O2-injured brain slices: TTC absorption level at 490 nm decreased with a 30-minute CP administration before and after injury. The TTC absorption values in the low- and high-dose group were significantly lower than the control group (P < 0.05–0.01). CP administration prior to insult had greater neuroprotective effects on brain slices than administration during the insult. CP Administration after insult had no obvious protective effects on the brain slices. There was no significant difference in TTC ab-sorption levels between administration after 2.5 hours and the model group (P > 0.05). ② Effects of CP on substances released from H2O2-induced injury slices were as follows: following incubation with 2 mmol/L H2O2 for 30 minutes, LDH release was significantly increased from the rat cortical and hippocampal brain slices. T-AOC and GSH were decreased, which is in accordance with the TTC assay for evaluating the de-gree of slice injury. Prior administration of 0.33 mg/L CP and 1.67 mg/L CP decreased LDH release and en-hanced T-AOC and GSH release in a dose-dependent manner. After H2O2-induced damage for 30 minutes, the release of SOD increased to some extent. SOD levels were further raised by pre-incubation with 0.33 mg/L CP or 1.67 mg/L CP, compared to the model group (P < 0.05).CONCLUSION: CP can protect rat cerebral cortex and hippocampal slices from H2O2-induced injury. This protective effect is dose-dependent. CP administration before injury is more effective than during or after injury.     

大鼠脑缺血再灌注损伤后皮层Homerla蛋白改变及意义

目的探讨大鼠脑血再灌注损伤后皮层组织Homerla蛋白的表达改变及其意义。方法选择成年雄性SD大鼠59只,随机分为正常对照组、缺血再灌注损伤后10rain、1h、3h、6h、12h、24h、48h及72h共9组,每组6只。免疫组化染色法和Western blot法测定Homerla蛋白含量,T-PCR法测定HomerlaRNA表达。结果在实验过程中5只动物死亡,54只进入结果分析。与对照组比较缺血再灌注损伤后Homerla蛋白和mRNA灰度值表达出现3个峰值,分别在10min、6h和24h,但在72h仍维持较高水平;与对照组Homerla蛋白免疫评分相比,缺血再灌注损伤后出现两个峰值,分别在6h和24h;Homerla蛋白除神经元外,在胶质细胞也表达。结论在缺血再灌注损伤后,Homerla出现3个表达高峰,可能在不同的机制的影响下对脑损伤发生发展起重要作用。     

Treatment with ginseng total saponins reduces the secondary brain injury in rat after cortical impact

The present study was designed to investigate the neuroprotective effect of ginseng total saponins (GTSs) and its underlying mechanisms in a rat model of traumatic brain injury (TBI). Rats were injected with GTSs (20 mg/kg, i.p.) or vehicle for 14 days after TBI. Neurological functions were determined using beam balance and prehensile traction tests at 1-14 days after trauma. Brain samples were extracted at 1 day after trauma for determination of water content, Nissl staining, enzyme-linked immunosorbent assay, immunohistochemistry, terminal deoxynucleotidyl transferase-mediated biotin-dUTP nick end labeling, and measurement of oxidative stress variables and inflammatory cytokines. Moreover, the dose response of the neuroprotective effect and time window of the efficacy of GTSs were also determined. We found that treatment of GTSs 1) improved the neurological function with an effective dosage of 5-80 mg/kg and an efficacy time window of 3-6 hr after TBI; 2) reduced brain water content and neuronal loss in the hippocampal CA3 area; 3) increased the activity of superoxide dismutase and decreased the activity of nitric oxide synthase and the amount of malondialdehyde and nitric oxide; 4) down-regulated interleukin-1β, interleukin-6, and tumor necrosis factor-α and upregulated interleukin-10 in the cortical area surrounding the injured core; and 5) inhibited the apoptotic cell death and expression of caspase-3 and bax and raised the expression of bcl-2. These findings suggest that administration of GTSs after TBI could reduce the secondary injury through inhibiting oxidative and nitrative stress, attenuating inflammatory response, and reducing apoptotic cell death.     

Proteomic identification of nitrated brain proteins in traumatic brain-injured rats treated postinjury with gamma-glutamylcysteine ethyl ester: insights into the role of elevation of glutathione as a potential therapeutic strategy for traumatic brain injury

Traumatic brain injury (TBI) occurs suddenly and has damaging effects to the brain that are dependent on the severity of insult. Symptoms can be mild, moderate, or severe. Oxidative damage is associated with traumatic brain injury through reactive oxygen/nitrogen species production. One such species, peroxynitrite, is elevated in TBI brain tissue (Orihara et al. [2001] Forensic Sci. Int. 123:142-149; Deng et al. [2007] Exp. Neurol. 205:154-165). Peroxynitrite can react with carbon dioxide and decompose to produce NO(2) and carbonate radicals, which in turn can lead to 3-nitrotyrosine, an index of protein nitration. Gamma-glutamylcysteine ethyl ester (GCEE) is an ethyl ester moiety of gamma-glutamylcysteine, an agent that up-regulates glutathione (GSH) production in brain (Drake et al. [2002] J. Neurosci. Res. 68:776-784). Many preclinical studies of TBI have employed pretreatment of animals with proposed beneficial agents prior to the injury itself. However, in the real world of TBI, treatment begins postinjury. Hence, insights into agents that improve outcome following injury are desperately needed. This study is one of the first to investigate a potential GSH-based therapy for TBI postinjury. Protein carbonyls, an index of protein oxidation, were significantly elevated in brain of animals subjected to TBI. However, if, after TBI, GCEE was administered i.p., protein carbonyl levels were significantly reduced. Similarly, 3-nitrotyrosine levels were elevated in brain following TBI but significantly decreased following TBI if GCEE was administered i.p. Redox proteomics analysis showed that several brain proteins were nitrated after TBI. However, if GCEE was given i.p. following TBI, many of these proteins were protected from nitration. The results are encouraging and are discussed with reference to potential therapeutic strategies for TBI involving elevated GSH.     

Apparent diffusion coefficient evaluation for secondary changes in the cerebellum of rats after middle cerebral artery occlusion

Supratentorial cerebral infarction can cause functional inhibition of remote regions such as the cerebellum, which may be relevant to diaschisis. This phenomenon is often analyzed using positron emission tomography and single photon emission CT. However, these methods are expensive and radioactive. Thus, the present study quantified the changes of infarction core and remote regions after unilateral middle cerebral artery occlusion using apparent diffusion coefficient values. Diffu- sion-weighted imaging showed that the area of infarction core gradually increased to involve the cerebral cortex with increasing infarction time. Diffusion weighted imaging signals were initially in- creased and then stabilized by 24 hours. With increasing infarction time, the apparent diffusion co- efficient value in the infarction core and remote bilateral cerebellum both gradually decreased, and then slightly increased 3-24 hours after infarction. Apparent diffusion coefficient values at remote regions （cerebellum） varied along with the change of supratentorial infarction core, suggesting that the phenomenon of diaschisis existed at the remote regions. Thus, apparent diffusion coefficient values and diffusion weighted imaging can be used to detect early diaschisis.     

Origins of histamine-containing fibers in the cerebral cortex of rats studied by immunohistochemistry with histidine decarboxylase as a marker and transection

The origins of histamine-containing fibers in the cerebral cortex were examined by means of the retrograde tracer technique of horseradish peroxidase (HRP)-immunohistochemistry with histidine decarboxylase (HDC) as a marker for the histamine neuron system. Total transection of the brain rostral to the posterior hypothalamus resulted in disappearance of HDC-like immunoreactive (HDCI) fibers in the cerebral cortex, but total transection caudal to the posterior hypothalamus did not decrease the number of HDCI fibers in the cortex, suggesting that HDCI fibers in the cerebral cortex originate in the posterior hypothalamus. The projection of HDCI neurons from the posterior hypothalamus to the cerebral cortex seemed to be bilateral because hemi-transection of the brain rostral to the posterior hypothalamus resulted in a bilateral decrease of HDCI fibers in the cerebral cortex with ipsilateral predominance. After injection of HRP into the cerebral cortex, numerous cells containing both HRP granules and HDCI structures were found bilaterally in the tuberal, caudal and postmamillary magnocellular nuclei, with ipsilateral predominance. These findings indicate that HDCI cells in the above nuclei give rise to axons extending bilaterally to the cerebral cortex.     

Origins of histamine-containing fibers in the cerebral cortex of rats studied by immunohistochemistry with histidine decar☐ylase as a marker and transection

The origins of histamine-containing fibers in the cerebral cortex were examined by means of the retrograde tracer technique of horseradish peroxidase (HRP)-immunohistochemistry with histidine decar☐ylase (HDC) as a marker for the histamine neuron system. Total transection of the brain rostral to the posterior hypothalamus resulted in disappearance of HDC-like immunoreactive (HDCI) fibers in the cerebral cortex, but total transection caudal to the posterior hypothalamus did not decrease the number of HDCI fibers in the cortex, suggesting that HDCI fibers in the cerebral cortex originate in the posterior hypothalamus. The projection of HDCI neurons from the posterior hypothalamus to the cerebral cortex seemed to be bilateral because hemi-transection of the brain rostral to the posterior hypothalamus resulted in a bilateral decrease of HDCI fibers in the cerebral cortex with ipsilateral predominance. After injection of HRP into the cerebral cortex, numerous cells containing both HRP granules and HDCI structures were found bilaterally in the tuberal, caudal and postmamillary magnocellular nuclei, with ipsilateral predominance. These findings indicate that HDCI cells in the above nuclei give rise to axons extending bilaterally to the cerebral cortex.