Vehicle-treated Ischemia Group Research Articles

Neuroprotection and reduced gliosis by atomoxetine pretreatment in a gerbil model of transient cerebral ischemia

Atomoxetine (ATX) is a non-stimulant selective norepinephrine reuptake inhibitor that is widely used for the treatment of attention-deficit/hyperactivity disorder (ADHD). In this study, we firstly examined neuroprotective effects of pre- or post-treatment with 15 and 30mg/kg ATX against ischemic damage in the gerbil hippocampal cornus ammonis 1 (CA1) region subjected to 5min of transient cerebral ischemia using cresyl violet staining, neuronal nuclei immunohistochemistry and Fluoro-J B histofluorescence staining. We found that only pre-treatment with 30mg/kg ATX protected CA1 pyramidal neurons from ischemic insult. In addition, pre-treatment with 30mg/kg ATX, which had neuroprotective effect against ischemic damage, distinctly attenuated the activation of astrocytes and microglia in the ischemic CA1 region compared with the vehicle-treated ischemia group by glial fibrillary acidic protein (for astrocytes) and ionized calcium-binding adapter molecule 1 (for microglia) immunohistochemistry. In brief, our present results indicate that ATX has neuroprotective effect against transient cerebral ischemic insult and that the neuroprotective effect of ATX may be closely associated with attenuated glial activation.

Neuroprotection of posttreatment with risperidone, an atypical antipsychotic drug, in rat and gerbil models of ischemic stroke and the maintenance of antioxidants in a gerbil model of ischemic stroke

Risperidone, an atypical antipsychotic drug, has been discovered to have some beneficial effects beyond its original effectiveness. The present study examines the neuroprotective effects of risperidone against ischemic damage in the rat and gerbil induced by transient focal and global cerebral ischemia, respectively. The results showed that pre- and posttreatment with 4 mg/kg risperidone significantly protected against neuronal death from ischemic injury. Many NeuN-immunoreactive neurons and a few F-J B-positive cells were found in the rat cerebral cortex and gerbil hippocampal CA1 region (CA1) in the risperidone-treated ischemia groups compared with those in the vehicle-treated ischemia group. In addition, treatment with risperidone markedly attenuated the activation of microglia in the gerbil CA1. On the other hand, we found that treatment with risperidone significantly maintained the antioxidants levels in the ischemic gerbil CA1. Immunoreactivities of superoxide dismutases 1 and 2, catalase, and glutathione peroxidase were maintained in the stratum pyramidale of the CA1; the antioxidants were very different from those in the vehicle-treated ischemia groups. In brief, our present findings indicate that posttreatment as well as pretreatment with risperidone can protect neurons in the rat cerebral cortex and gerbils CA1 from transient cerebral ischemic injury and that the neuroprotective effect of risperidone may be related to attenuation of microglial activation as well as maintenance of antioxidants.

Chlorogenic Acid Attenuates Ventricular Remodeling After Myocardial Infarction in Mice

Chlorogenic acid (CGA), which is a key component of coffee, has many biological effects such as anti-inflammation activity. However, the effects of CGA on ventricular remodeling after myocardial ischemia have not been well investigated. To test the hypothesis that CGA can attenuate chronic ventricular remodeling after myocardial ischemia, we orally administered CGA to murine myocardial ischemia models. Seven to nine week-old C57BL/6 mice were used. A myocardial infarction (MI) model was produced by permanent ligation of the left anterior descending coronary artery (LAD) using an 8-0 suture passed under the arteries. These mice were randomly assigned into 4 groups in each experimental model. Some MI mice were supplemented orally with CGA (30 mg/kg/day, MI+CGA group, n = 13) as a CGAtreated MI group, and other MI mice received vehicle (MI+vehicle group, n = 11) as a vehicle-treated MI group. Shamoperated mice without MI also received vehicle (Sham+vehicle group, n = 3) as a sham group, and sham-operated mice without MI received CGA (30 mg/kg/day, Sham+CGA group, n = 8) as a Sham+CGA group. Just before sacrifice on day 14, we measured blood pressure and heart rate and performed echocardiography. We obtained 3 transverse sections per heart for histopathologic examination. There were no differences in body weight, heart rate, or blood pressure among the groups on day 14. The vehicle-treated MI group showed significantly impaired left ventricular contraction compared to the sham-operated group. However, the CGA-treated MI group showed significantly improved ventricular contraction compared to the vehicle-treated MI group. Severe myocardial fibrosis with enhanced macrophage infiltration was observed in the vehicle-treated ischemia group on day 14. CGA attenuated these fibrotic changes with suppressed macrophage infiltration without systemic adverse effects. CGA may effectively suppress chronic ventricular remodeling after myocardial ischemia because it is critically involved in the suppression of macrophage infiltration.

Neuroprotective effects of Alpinia katsumadai against experimental ischemic damage via control of oxidative stress

Context: Alpinia katsumadai (Zingiberaceae) has been identified by the National Plant Quarantine Service in Korea. The extract of Alpinia katsumadai seed (EAKS) has antioxidant activities.Objective: We investigated the neuroprotective effects of EAKS on ischemic damage in the gerbil hippocampal CA1 region after transient cerebral ischemia.Materials and methods: The ethanol extract of EAKS was obtained by organic solvent, collected in Kangwon province (South Korea) and orally administered using a feeding needle once a day for one week before transient cerebral ischemia in gerbils.Result: We adapted oral administration of 25 and 50 mg/kg EAKS because there are no data about the absorption and metabolism of EKAS. We found a significant neuroprotection in the 50 mg/kg EAKS-treated ischemia group, not in the 25 mg/kg EAKS-treated ischemia group, at 4 days ischemia-reperfusion (I-R). In the 50 mg/kg EAKS-treated ischemia group, about 68% of pyramidal neurons in the CA1 region were immunostained with neuronal nuclei (NeuN) 4 days after I-R, compared to the vehicle-treated ischemia group. 8-Hydroxy-2′-deoxyguanosine (a marker for DNA damage) and 4-hydroxy-2-nonenal (a marker for lipid peroxidation) immunoreactivity in the CA1 region of the EAKS-treated ischemia group were not markedly changed compared to the vehicle-treated ischemia group. In addition, Cu,Zn- and Mn-SOD immunoreactivity in the CA1 region of the EAKS-treated ischemia group were increased compared to the vehicle-treated ischemia group.Discussion: Repeated supplements of EAKS could protect neurons against ischemic damage, showing that DNA damage and lipid peroxidation are attenuated and SODs are increased in the ischemic CA1 region.

Neuroprotective Effects of PEP-1-Cu,Zn-SOD against Ischemic Neuronal Damage in the Rabbit Spinal Cord

A rabbit model of spinal cord ischemia has been introduced as a good model to investigate the pathophysiology of ischemia-reperfusion (I-R)-induced paraplegia. In the present study, we observed the effects of Cu,Zn-superoxide dismutase (SOD1) against ischemic damage in the ventral horn of L(5-6) levels in the rabbit spinal cord. For this study, the expression vector PEP-1 was constructed, and this vector was fused with SOD1 to create a PEP-1-SOD1 fusion protein that easily penetrated the blood-brain barrier. Spinal cord ischemia was induced by transient occlusion of the abdominal aorta for 15 min. PEP-1-SOD1 (0.5 mg/kg) was intraperitoneally administered to rabbits 30 min before ischemic surgery. The administration of PEP-1-SOD1 significantly improved neurological scores compared to those in the PEP-1 (vehicle)-treated ischemia group. Also, in this group, the number of cresyl violet-positive cells at 72 h after I-R was much higher than that in the vehicle-treated ischemia group. Malondialdehyde levels were significantly decreased in the ischemic spinal cord of the PEP-1-SOD1-treated ischemia group compared to those in the vehicle-treated ischemia group. In contrast, the administration of PEP-1-SOD1 significantly ameliorated the ischemia-induced reduction of SOD and catalase levels in the ischemic spinal cord. These results suggest that PEP-1-SOD1 protects neurons from spinal ischemic damage by decreasing lipid peroxidation and maintaining SOD and catalase levels in the ischemic rabbit spinal cord.

Neuroprotective Effects of Alpinia Katsumadai Against Neuronal Damage in the Gerbil Hippocampus Induced by Transient Cerebral Ischemia

ABSTRACTAlpinia katsumadai, one of the family Zingiberaceae, contains chalcone, flavonoids, diarylheptanoids, monoterpenes, sesquiterpenoids, stilbenes, and labdanes. It has been reported that the extract of Alpinia katsumadai seed (EAKS) has antiinflammatory effects, and enhances antioxidant activities. We observed the neuroprotective effects of EAKS against ischemic damage in gerbils received oral administrations of EAKS (50 mg/kg) once a day for 7 days before transient cerebral ischemia. In the EAKS-treated ischemia group, neuronal nuclei (NeuN, a marker for neurons)-immunoreactive pyramidal neurons were abundant (68.3% of the sham group) in the hippocampal CA1 region (CA1) 4 days after ischemia/reperfusion (I/R) compared to those in the vehicle-treated ischemia group (13.18%). We also observed that EAKS treatment significantly decreased the activation of astrocytes and microglia in the CA1 compared with the vehicle-treated ischemia group 4 days postischemia. In addition, protein levels of GFAP and Iba-1 in the EAKS-treated ischemia group were much lower than those in the vehicle-treated ischemia group 4 days after I/P. Our findings indicate that the repeated supplements of EAKS could protect neurons from an ischemic damage, showing that glial activation is markedly decreased in the ischemic area.

Ethyl Acetate Extracts of Raw and Steamed Codonopsis lanceolata Protects Against Ischemic Damage Potentially by Maintaining SOD1 and BDNF Levels

ABSRACTWe observed the neuroprotective effects of ECLs treatment on ischemic damage in the gerbil hippocampal CA1 region four days after an ischemic insult. Among the 10 ECLs, EERCL and EESCL showed significant neuroprotection: the percentage of neurons remaining after treatment with EERCL and EESCL was 72.7% and 68.4% of that seen in the sham-ischemia group, respectively. The administration of EERCL and EESCL significantly decreased the reactive gliosis of microglia compared with that seen in the vehicle-treated ischemia group. In addition, SOD1 and BDNF immunoreactivity in the EERCL- and EESCL-ischemia groups were markedly increased compared with that in the vehicle-treated ischemia group. These results suggest that the administration of EERCL and EESCL can reduce ischemic neuronal loss potentially by maintaining SOD1 and BDNF immunoreactivity in the ischemic hippocampal CA1 region.

Extract from Terminalia chebula Seeds Protect Against Experimental Ischemic Neuronal Damage Via Maintaining SODs and BDNF Levels

The fruit of Terminalia chebula Retz has been used as a traditional medicine in Asia and contains tannic acid, chebulagic acid, chebulinic acid and corilagin. Extract from T. chebula seeds (TCE) has various biological functions. We observed the neuroprotective effects of TCE against ischemic damage in the hippocampal C1 region (CA1) of the gerbil that had received oral administrations of TCE (100mg/kg) once a day for 7days before the induction of transient cerebral ischemia. In the TCE-treated ischemia group, neuronal neuclei (a marker for neurons)-positive neurons were distinctively abundant (62% of the sham group) in the CA1 4days after ischemia-reperfusion (I-R) compared to those (12.2% of the sham group) in the vehicle-treated ischemia group. Four days after I-R TCE treatment markedly decreased the activation of astrocytes and microglia in the ischemic CA1 compared with the vehicle-treated ischemia group. In addition, immunoreactivities of Cu, Zn-superoxide dismutase (SOD1), Mn-superoxide dismutase (SOD2) and brain-derived neurotrophic factor (BDNF) in the CA1 of the TCE-treated ischemia group were much higher than those in the vehicle-ischemia group 4days after I-R. Protein levels of SOD1, SOD2 and BDNF in the TCE-treated ischemia group were also much higher than those in the vehicle-ischemia group 4days after I-R. These results indicate that the repeated supplement of TCE protected neurons from ischemic damage induced by transient cerebral ischemia by maintaining SODs and BDNF levels as well as decreasing glial activation.

Leptin's neuroprotective action in experimental transient ischemic damage of the gerbil hippocampus is linked to altered leptin receptor immunoreactivity

Circulating leptin crosses blood–brain barrier to provide control of feeding behavior and energy balance. We investigated changes in leptin and leptin receptor (ObR) in the gerbil hippocampal CA1 region (CA1) after transient cerebral ischemia, and examined effects of leptin on ischemic damage. In vehicle-treated ischemia (vehicle-ischemia) group, the number of survived neurons in the CA1 was 16.4% compared to vehicle-treated sham (vehicle-sham) group; however, in 1mg/kg leptin-treated ischemia (leptin-ischemia) group, 77.5% of neurons of the CA1 has survived. In the vehicle-sham group, weak leptin immunoreactivity was detected in CA1 neurons. From 4days post-ischemia, moderate leptin immunoreactivity was expressed in CA1 neurons. In the leptin-ischemia group, leptin immunoreactivity at 5days post-ischemia was higher than the sham group. ObR immunoreaction in the sham group was hardly detected in any cells. From 2days post-ischemia, ObR immunoreaction was expressed in microglia, showing the highest immunoreactivity at 5days post-ischemia. Microglial activation in the leptin-ischemia group was hardly detected at 5days post-ischemia; however, astrocytes in the group were slightly increased compared to the vehicle-ischemia group. These suggest that treatment of leptin has neuroprotective effects against ischemic damage, showing that ObR immunoreactivity is distinctly changed in the ischemic CA1.

Neuroprotection ofAlpinia katsumadaiSeed Extract against Neuronal Damage in the Ischemic Gerbil Hippocampus is Linked to Altered Brain-Derived Neurotrophic Factor

The extract of Alpinia katsumadai, a member of the family Zingiberaceae, shows anti-inflammatory effects and antioxidant activity. We observed the neuroprotective effects of the extract from Alpinia katsumadai seed (EAKS) against ischemic damage in gerbils administered oral EAKS (25, and 50 mg/kg) once a day for 7 days before transient cerebral ischemia. In the 50 mg/kg EAKS-treated ischemia group, about 67% of neurons in the hippocampal CA1 region (CA1) survived after ischemia/reperfusion (I/R) based on cresyl violet staining. We observed that EAKS treatment significantly maintained brain-derived neurotrophic factor (BDNF) immunoreactivity in the ischemic CA1 region after I/R. In addition, protein levels of BDNF in the 50 mg/kg EAKS-treated ischemia group were much higher than those in the vehicle-treated ischemia group after I/R. These findings indicate that repeated supplementation of EAKS protects neurons from ischemic damage, such that BDNF is distinctively maintained in ischemic areas.

Maintenance of anti-inflammatory cytokines and reduction of glial activation in the ischemic hippocampal CA1 region preconditioned with lipopolysaccharide

Lipopolysaccharide (LPS) induces a strong immune response, and pretreatment with low dose of LPS suppresses the production of proinflammatory mediators. In the present study, we investigated the effect of LPS preconditioning on the delayed neuronal death in the gerbil hippocampal CA1 region after 5min of transient cerebral ischemia. LPS preconditioning showed neuroprotective effects against ischemic damage in the hippocampal CA1 region after ischemic insult: About 92% of neurons in the CA1 region survived in the LPS-treated ischemia group. LPS preconditioning maintained anti-inflammatory cytokines, such as interleukin (IL)-4 and IL-13, in pyramidal neurons in the CA1 region after ischemia/reperfusion. In addition, IL-4 and IL-13 protein levels in the CA1 region of the LPS-treated ischemia group were similar to the vehicle-treated sham group. We found that reactive gliosis was markedly attenuated in the CA1 region of the LPS-treated ischemia group compared to the vehicle-treated ischemia group using immunohistochemistry of glial fibrillary acidic protein for astrocytes, and ionized calcium-binding adapter molecule 1 and isolectin B4 for microglia. These results indicate that LPS preconditioning may provide neuroprotection in the ischemic hippocampal CA1 region via maintenance of anti-inflammatory cytokines and suppression of glial activation.

Zizyphus Attenuates Ischemic Damage in the Gerbil Hippocampus via Its Antioxidant Effect

The fruit of Zizyphus jujuba has been used as a traditional Chinese medicinal herb and considered for thousands of years to affect various physiological functions in the body. We obtained a Z. jujuba extract (ZJE) and observed the neuroprotective effects of ZJE against ischemic damage in gerbils that had received repeated oral administrations of ZJE for 10 days. In the ZJE-treated ischemia group, neuronal nuclei (a marker for neurons)-immunoreactive neurons were abundant (58.4% vs. sham group) in the hippocampal CA1 region 4 days after ischemia/reperfusion compared to those in the vehicle-treated ischemia group (11.3%). In addition, ZJE treatment significantly decreased the reactive gliosis of astrocytes and microglia in the CA1 region compared to that in the vehicle-treated group 4 days after ischemia/reperfusion. Immunoreactivities of Cu,Zn-superoxide dismutase (SOD1) and brain-derived neurotrophic factor in the ZJE-treated ischemia group were higher those in the vehicle-treated ischemia group 4 days after ischemia/reperfusion. In addition, in the ZJE-treated ischemia group, levels of hydroxynonenal, an indicator of lipid peroxidation, were much lower than those in the vehicle-treated ischemia group after ischemia/reperfusion. These results suggest that the repeated supplements of ZJE can protect neurons from ischemic damage via up-regulation of SOD1 and reduction of lipid peroxidation in the ischemic hippocampal CA1 region.

Arylalkylamine N-acetyltransferase (AANAT) is expressed in astrocytes and melatonin treatment maintains AANAT in the gerbil hippocampus induced by transient cerebral ischemia

Melatonin is synthesized from serotonin by the action of arylalkylamine N-acetyltransferase (AANAT) and hydroxyindole- O-methyltransferase. In this study, we observed cellular changes of arylalkylamine N-acetyltransferase (EC 2.3.1.87; AANAT) in the hippocampal CA1 region at various time points after ischemia/reperfusion. In vehicle-treated sham group, AANAT immunoreaction was detected in pyramidal neurons of the CA1 region. AANAT immunoreactivity in the neurons was highest 2 days and disappeared from 4 days after ischemia/reperfusion. From 3 days after ischemia/reperfusion, AANAT immunoreaction was expressed in astrocytes in the strata oriens and radiatum of the CA1 region. AANAT protein and mRNA levels were significantly increased 2 days after ischemia/reperfusion, and markedly decreased from 5 days after ischemia/reperfusion. The repeated administration of melatonin (10 mg/kg, i.p.) 3 times (once a day) to gerbils before ischemia/reperfusion significantly reduced ischemia-induced hyperactivity as well as neuronal death compared to those in the vehicle-treated ischemia group. Melatonin treatment also maintained AANAT immunoreactivity and its protein levels in the CA1 region after ischemia/reperfusion. These results suggest that the reduction of AANAT in ischemic CA1 region is associated with delayed neuronal death following transient ischemia, and melatonin treatment shows neuroprotection with maintenance of AANAT levels in the ischemic CA1 region.

Benzamide protects delayed neuronal death and behavioural impairment in a mouse model of global cerebral ischemia

The present study is aimed at evaluating the functional and neuroprotective effect of benzamide, a poly-(ADP-ribose) polymerase (PARP) inhibitor on delayed neuronal death (DND) in hippocampus CA1 region and memory impairment following global cerebral ischemia (GCI) in a mouse model. GCI was induced by bilateral common carotid artery occlusion (BCAo) for 20 min followed by reperfusion for 9 days. Postischemic continuous treatment with benzamide (160 mg/kg b w i.p. for 9 days) significantly reversed the GCI-induced anterograde memory impairment in passive avoidance step through and elevated plus maze tasks. The observed memory impairment in vehicle treated ischemia group was found to be well correlated with DND and downregulation of cholinergic muscarinic receptor-1 expression, which was possibly mediated by inflammation and apoptosis, as revealed from inducible nitric oxide synthase (iNOS) expression and number of TUNEL positive neurons in hippocampus CA1 region. It is clear from the present experiment that benzamide treatment significantly decreases the iNOS expression and number of apoptotic neurons and thereby improves the neuronal survival and memory during GCI. Our present findings provide compelling evidence that multiple doses of benzamide treatment is a promising therapeutic approach for cerebrovascular and neurodegenerative diseases, which deserves further clinical evaluation.