Systemic administration of sunflower oil exerts neuroprotection in a mouse model of transient focal cerebral ischaemia.

OBJECTIVES: Natural products are valuable sources of nutraceuticals for the prevention or treatment of ischemic stroke, a major cause of death and severe disability worldwide. Among the mechanisms implicated in cerebral ischemia-reperfusion damage, oxidative stress exerts a pivotal role in disease progression. Given the high antioxidant potential of most components of sunflower oil, we have explored its effects on ischemic brain injury produced in the mouse by transient occlusion of the middle cerebral artery (MCAo). KEY FINDINGS: Intraperitoneal (i.p.) administration of sunflower oil at doses of 3 ml/kg (48 h, 24 h and 1 h before MCAo) significantly reduced brain infarct volume and oedema assessed 24 h after the insult. This neuroprotective treatment schedule also prevented the elevation of brain lipid peroxidation produced by MCAo-reperfusion injury. By contrast, doses of 0.03 ml/kg of sunflower oil resulted ineffective on both cerebral damage and lipid peroxidation. Although sunflower oil did not affect serum levels of Diacron-reactive oxygen metabolites (d-ROMs), both 0.03 and 3 ml/kg dosing regimens resulted in the preservation of serum biological antioxidant potential (BAP) that was otherwise dramatically reduced 24 h after MCAo. CONCLUSIONS: Sunflower oil represents a promising source of neuroprotective extracts/compounds that can be exploited for the prevention and/or treatment of cerebral ischemia.

Cannabidiol Confers Neuroprotection in Rats in a Model of Transient Global Cerebral Ischemia: Impact of Hippocampal Synaptic Neuroplasticity.

Evidence for the clinical use of neuroprotective drugs for the treatment of cerebral ischemia (CI) is still greatly limited. Spatial/temporal disorientation and cognitive dysfunction are among the most prominent long-term sequelae of CI. Cannabidiol (CBD) is a non-psychotomimetic constituent of Cannabis sativa that exerts neuroprotective effects against experimental CI. The present study investigated possible neuroprotective mechanisms of action of CBD on spatial memory impairments that are caused by transient global cerebral ischemia (TGCI) in rats. Hippocampal synaptic plasticity is a fundamental mechanism of learning and memory. Thus, we also evaluated the impact of CBD on neuroplastic changes in the hippocampus after TGCI. Wistar rats were trained to learn an eight-arm aversive radial maze (AvRM) task and underwent either sham or TGCI surgery. The animals received vehicle or 10 mg/kg CBD (i.p.) 30 min before surgery, 3 h after surgery, and then once daily for 14 days. On days 7 and 14, we performed a retention memory test. Another group of rats that received the same pharmacological treatment was tested in the object location test (OLT). Brains were removed and processed to assess neuronal degeneration, synaptic protein levels, and dendritic remodeling in the hippocampus. Cannabidiol treatment attenuated ischemia-induced memory deficits. In rats that were subjected to TGCI, CBD attenuated hippocampal CA1 neurodegeneration and increased brain-derived neurotrophic factor levels. Additionally, CBD protected neurons against the deleterious effects of TGCI on dendritic spine number and the length of dendritic arborization. These results suggest that the neuroprotective effects of CBD against TGCI-induced memory impairments involve changes in synaptic plasticity in the hippocampus.

Effects of the methanol fraction of modified Seonghyangjeongki-san water extract on transient ischaemic brain injury in mice.

CONTEXT: Recently in Korean medicine, the antioxidant and anti-inflammatory activities of Seonghyangjeongki-san (SHJKS) were reported. However, studies on the specific mechanisms of action of SHJKS for the treatment of ischaemic stroke are still lacking. OBJECTIVE: This study investigates the mechanism of action of the water extract methanol fraction of modified SHJKS (SHJKSmex) on cerebral ischaemic injury. MATERIALS AND METHODS: C57BL/6 male mice were orally administered SHJKSmex (30, 100, or 300 mg/kg) for 3 consecutive days (2 days, 1 day, and 1 h, respectively) before middle cerebral artery occlusion (MCAO). Twenty-four hours after MCAO, the infarct volumes were measured, brain edoema indices were calculated, and neurological deficit scores were determined. Inflammation-related substances in the ipsilateral hemisphere were determined by western blotting, dichlorofluorescin diacetate, thiobarbituric acid-reactive substances assay, and enzyme-linked immunosorbent assay. RESULTS: SHJKSmex pre-treatment at 300 mg/kg decreased infarct volume by 87% and mean brain water content by 90% of the MCAO control group. Moreover, SHJKSmex effectively suppressed the expression of inducible nitric oxide synthase, reactive oxygen species, interleukin 1, and caspases-8 and -9 and increased the B-cell lymphoma 2/Bcl-2-associated X protein ratio (Bcl-2/Bax) in ischaemic mouse brain. The hippocampal pyramidal cell densities were significantly increased in the 300 mg/kg SHJKSmex-administered group compared to the MCAO control group. DISCUSSION AND CONCLUSIONS: SHJKSmex protected the brain from ischaemic stroke in mice through its antioxidant, anti-inflammatory, and antiapoptotic activities. Our findings suggest that SHJKSmex is a promising therapeutic candidate for the development of a new formulation for ischaemia-induced brain damage.

Amiloride Alleviates Neurological Deficits Following Transient Global Ischemia and Engagement of Central IL-6 and TNF-α Signal.

BACKGROUND: Central pro-inflammatory cytokine (PIC) signal is involved in neurological deficits after transient global ischemia induced by cardiac arrest (CA). The present study was to examine if blocking acid sensing ion channels (ASICs) using amiloride in the Central Nervous System can alleviate neurological deficits after the induction of CA and further examine the participation of PIC signal in the hippocampus for the effects of amiloride. METHODS: CA was induced by asphyxia and then cardiopulmonary resuscitation was performed in rats. Western blot analysis and ELISA were used to determine the protein expression of ASIC subunit ASIC1 in the hippocampus, and the levels of PICs. As noted, it is unlikely that this procedure is clinically used although amiloride and other pharmacological agents were given into the brain in this study. RESULTS: CA increased ASIC1 in the hippocampus of rats in comparison with control animals. This was associated with the increase in IL-1ß, IL-6 and TNF-α together with Caspase-3 and Caspase-9. The administration of amiloride into the lateral ventricle attenuated the upregulation of Caspase-3/Caspase-9 and this further alleviated neurological severity score and brain edema. Inhibition of central IL-6 and TNF-α also decreased ASIC1 in the hippocampus of CA rats. CONCLUSION: Transient global ischemia induced by CA amplifies ASIC1a in the hippocampus likely via PIC signal. Amiloride administered into the Central Nervous System plays a neuroprotective role in the process of global ischemia. Thus, targeting ASICs (i.e., ASIC1a) is suggested for the treatment and improvement of CA-evoked global cerebral ischemia.

Molecular Alterations and Effects of Acute Dehydroepiandrosterone Treatment Following Brief Bilateral Common Carotid Artery Occlusion: Relevance to Transient Ischemic Attack.

Transient ischemic attack (TIA) represents brief neurological dysfunction of vascular origin without detectable infarction. Despite major clinical relevance characterization of post-TIA molecular changes using appropriate experimental model is lacking and no therapeutic agent has been established yet. Neurosteroid dehydroepiandrosterone (DHEA) arose as one of the candidates for cerebral ischemia treatment but its effects on TIA-like condition remain unknown. Seeking an animal model applicable for investigation of molecular alterations in mild ischemic conditions such as TIA, 15-min bilateral common carotid artery occlusion with 24-h reperfusion was performed to induce ischemia/ reperfusion (I/R) injury in adult male Wistar rats. Additionally, effects of 4-h post-operative DHEA treatment (20 mg/kg) were investigated in physiological and I/R conditions in hippocampus (HIP) and prefrontal cortex (PFC). The study revealed absence of sensorimotor deficits, cerebral infarcts and neurodegeneration along with preserved HIP and PFC overall neuronal morphology and unaltered malondialdehyde and reduced glutathione level following I/R and/or DHEA treatment. I/R induced nitric oxide burst in HIP and PFC was accompanied with increased neuronal nitric oxide synthase protein level exclusively in HIP. DHEA had no effects in physiological conditions, while increase of Bax/Bcl2 ratio and dissipation of mitochondrial membrane potential in treated I/R group suggested DHEA-mediated exacerbation of post-ischemic changes that might lead to pro-apoptotic events in HIP. Interestingly, DHEA restored I/R-induced NO to the control level in PFC. Obtained results indicated that I/R may serve as an appropriate model for investigation of molecular changes and treatment outcome following mild ischemic conditions such as TIA.

Xuebijing enhances neuroprotective effects of ulinastatin on transient cerebral ischemia via Nrf2-are signal pathways in the hippocampus.

Prior studies have demonstrated that ulinastatin (UTI) plays a beneficial role in regulating cerebral ischemic injury evoked by cardiac arrest (CA). It is noteworthy to find interventions that can enhance effects of this drug and thereby increase its clinical application. Xuebijing (XBJ) is comprised of extracts from Chinese herbs and has been widely used in China as an anti-endotoxicity drug for the treatment of sepsis and ischemic disorders associated with multiple organ dysfunction syndrome. Thus, in this study we examined the effects of a combination of UTI and XBJ to improve neural injury in the process of neurological functions after transient cerebral ischemia. Our results show that CA impaired Nrf2- antioxidant response element (Nrf2-ARE) and superoxide dismutase (SOD) in the hippocampus CA1 region. This process further amplified products of oxidative stress, namely 8-isoprostaglandin F2α (8-iso PGF2α) and 8-hydroxy-2'-deoxyguanosine (8-OHdG). A lower dose of UTI failed to restore Nrf2-ARE and attenuate 8-iso PGF2α and 8-OHdG SOD following CA; however, systemic administration of XBJ amplified the effects of this dose of UTI on antioxidative signal pathway of the hippocampus. Overall, the results of this study have implications for the enhanced neuroprotective role played by a combination of XBJ and UTI in improving neural injury observed in transient cerebral ischemia; and Nrf2-ARE signal is a part of key mechanisms that are involved in neuroprotective effects of XBJ and UTI.

A Combination of Ulinastatin and Xuebijing Amplifies Neuroprotection after Transient Cerebral Ischemia via Attenuating Apoptosis Signal Pathways in Hippocampus.

BACKGROUND: Ulinastatin (UTI) plays the beneficial roles in modifying cerebral ischemic injury evoked by cardiac arrest (CA). XueBiJing (XBJ), comprised of extracts from Chinese herbals, has been used for the treatment of sepsis and ischemic disorders linked to multiple organ dysfunction syndromes. The current study was to find interventions that can enhance effectiveness of these drugs and further to provide a fundamental for their rational application in clinical practice. Thus, we examined how apoptosis signal in the hippocampus is engaged in a facilitating role of UTI and XBJ in improving neural injury and neurological functions after transient cerebral ischemia. METHODS: CA was induced by asphyxia followed by cardiopulmonary resuscitation in rats. Western Blot analysis and ELISA were employed to determine the protein expression of Caspase-3 and Caspase-9 in the hippocampus; and representative apoptosis pathways. The modified neurological severity score (mNSS) and spatial working memory performance were used to assess neurological deficiencies in CA rats. RESULTS: CA increased Caspase-3 and Caspase-9 in the hippocampus CA1 region. A lower dose of UTI did not attenuate upregulation of apoptosis signal pathways evoked by CA. However, a systemic administration of XBJ significantly amplified the inhibitory effects of the lower dose of UTI on apoptosis signal of the hippocampus. In addition, a combination of UTI and XBJ improved mNSS and spatial working memory performance to a greater degree. CONCLUSIONS: Our data indicate that a combination of XBJ and UTI plays a facilitating role in improving neuronal injury and neurological deficits observed in transient cerebral ischemia; and an inhibition of apoptosis signal pathways is involved in neuroprotective effects of united XBJ and UTI.

Pre­treatment with Chrysanthemum indicum Linné extract protects pyramidal neurons from transient cerebral ischemia via increasing antioxidants in the gerbil hippocampal CA1 region.

Chrysanthemum indicum Linné extract (CIL) is used in herbal medicine in East Asia. In the present study, gerbils were orally pre­treated with CIL, and changes of antioxidant enzymes including superoxide dismutase (SOD) 1 and SOD2, catalase (CAT) and glutathione peroxidase (GPX) in the hippocampal CA1 region following 5 min of transient cerebral ischemia were investigated and the neuroprotective effect of CIL in the ischemic CA1 region was examined. SOD1, SOD2, CAT and GPX immunoreactivities were observed in the pyramidal cells of the CA1 region and their immunoreactivities were gradually decreased following ischemia­reperfusion and barely detectable at 5 days post­ischemia. CIL pre­treatment significantly increased immunoreactivities of SOD1, CAT and GPX, but not SOD2, in the CA1 pyramidal cells of the sham­operated animals. In addition, SOD1, SOD2, CAT and GPX immunoreactivities in the CA1 pyramidal cells were significantly higher compared with the ischemia­operated animals. Furthermore, it was identified that pre­treatment with CIL protected the CA1 pyramidal cells in the CA1 region using neuronal nuclei immunohistochemistry and Fluoro­Jade B histofluorescence staining; the protected CA1 pyramidal cells were 67.5% compared with the sham­operated animals. In conclusion, oral CIL pre­treatment increased endogenous antioxidant enzymes in CA1 pyramidal cells in the gerbil hippocampus and protected the cells from transient cerebral ischemic insult. This finding suggested that CIL is promising for the prevention of ischemia­induced neuronal damage.

Astragaloside IV attenuates cognitive impairments induced by transient cerebral ischemia and reperfusion in mice via anti-inflammatory mechanisms.

Astragaloside IV (AS-IV) is the main active component isolated from the traditional Chinese medicinal herb Astragalus membranaceus. Studies have demonstrated that AS-IV has neuroprotective effects in cerebral ischemic models. In this study, we aimed to investigate the effects of AS-IV on memory impairment induced by transient cerebral ischemia and reperfusion in mice, as well as the associated signaling mechanisms. Severe memory deficits were induced by bilateral common carotid artery occlusion (BCCAO) in mice as indicated in the Morris water maze test in this study. Oral administration of AS-IV (10 and 20mg/kg, once per day, started 7days before surgery and continued for 7days after surgery) significantly attenuated memory impairment and neuroinflammation. Moreover, AS-IV treatment significantly reduced the expression of toll-like receptor-4 (TLR4) and its downstream adaptor proteins, including myeloid differentiation primary response gene 88 (MyD88), toll/interleukin-1 receptor-domain containing adaptor-inducing interferon-ß (TRIF) and tumour necrosis factor receptor associated factor-6 (TRAF6), and subsequently inhibited NF-κB phosphorylation. It is well-known that cerebral ischemia and reperfusion injury enhances the formation of reactive oxygen species (ROS) and further neuroinflammation. Importantly, we found that AS-IV suppressed NLRP3 inflammasome activation by controlling ROS production. In addition, AS-IV markedly reduced overactivation of microglia and the overexpression of inflammatory cytokines in the hippocampus compared with the transient cerebral ischemia and reperfusion group. These results suggest that AS-IV might possess neuroprotective effects against transient cerebral ischemia and reperfusion partly through its anti-inflammatory effects by inhibiting TLR4 signaling pathway and NLRP3 inflammasome overactivation.

Hyperbaric oxygen and hyperbaric air preconditioning induces ischemic tolerance to transient forebrain ischemia in the gerbil.

Ischemic preconditioning with sublethal stress triggers defensive mechanisms against ischemic brain damage; however, such manipulations are potentially dangerous and, therefore, safe stimuli have been sought. Hyperoxia preconditioning by administration of hyperbaric (HBO) or normobaric oxygen (NBO) may have neuroprotective potential. The aim of this study was to determine whether preconditioning with HBO and air (HBA) applied at 2.5 absolute pressure (ATA) or NBO preconditioning induces ischemic tolerance in the brain of gerbils subjected to 3min transient cerebral ischemia. Neuronal cell survival, changes in brain temperature, the generation of factors involved in neurodegeneration and basic behavior in nest building were all tested. Hyperoxic preconditioning prevented ischemia-induced neuronal cell loss, reduced the number of TUNEL positive cells in the CA1 region of the hippocampus and improved the nest building process compared to untreated ischemic animals. Preconditioning also suppressed the production of reactive oxygen species and increased Bax expression normally observed after an ischemic episode. Only HBO preconditioning inhibited ischemia-evoked increases in brain temperature. Our results show that hyperoxic preconditioning results in induction of ischemic tolerance and prevents ischemia-induced neuronal damage in the gerbil brain. Pressurized air preconditioning was as effective as HBO or NBO preconditioning in providing neuroprotection. The observed neuroprotection probably results from mild oxidative stress evoked by increased brain tissue oxidation and activation of antioxidant and antiapoptotic defenses.

GlyT1 Inhibitor NFPS Exerts Neuroprotection via GlyR Alpha1 Subunit in the Rat Model of Transient Focal Cerebral Ischaemia and Reperfusion.

BACKGROUND/AIMS: Glycine is a strychnine-sensitive inhibitory neurotransmitter in the central nervous system (CNS), especially in the spinal cord, brainstem, and retina. The objective of the present study was to investigate the potential neuroprotective effects of GlyT1 inhibitor N [3-(4'-fluorophenyl)-3-(4'-phenylphenoxy) propyl] sarcosine (NFPS) in the rat model of experimental stroke. METHODS: In vivo ischaemia was induced by transient middle cerebral artery occlusion (tMCAO). The methods of Western Blotting, Nissl Staining and Morris water maze methods were applied to analyze the anti-ischaemia mechanism. RESULTS: The results showed that high dose of NFPS (H-NFPS) significantly reduced infarct volume, neuronal injury and the expression of cleaved caspase-3, enhanced Bcl-2/Bax, and improved spatial learning deficits which were administered three hours after transient middle cerebral artery occlusion (tMCAO) induction in rats, while, low dose of NFPS (L-NFPS) exacerbated the injury of ischaemia. These findings suggested that low and high dose of NFPS produced opposite effects. Importantly, it was demonstrated that H-NFPS-dependent neuronal protection was inverted by salicylate (Sal), a specific GlyR x0251;1 antagonist. Such effects could probably be attributed to the enhanced glycine level in both synaptic and extrasynaptic clefts and the subsequently altered extrasynaptic GlyRs and their subtypes. CONCLUSIONS: These data imply that GlyT1 inhibitor NFPS may be a novel target for clinical treatment of transient focal cerebral ischaemia and reperfusion which are associated with altered GlyR alpha 1 subunits.

Postischemic fish oil treatment restores long-term retrograde memory and dendritic density: An analysis of the time window of efficacy.

We reported that fish oil (FO) prevented the loss of spatial memory caused by transient, global cerebral ischemia (TGCI), provided the treatment covered the first days prior to and after ischemia. Continuing these studies, trained rats were subjected to TGCI, and FO was administered for 10days, with a time window of efficacy (TWE) of 4, 8 or 12h post-ischemia. Retrograde memory was assessed up to 43days after TGCI. In another experiment, ischemic rats received FO with a 4- or 12-h TWE, and dendritic density was assessed in the hippocampus and cerebral cortex. The brain lipid profile was evaluated in sham-operated and ischemic rats that were treated with FO or vehicle with a 4-h TWE. Ischemia-induced retrograde amnesia was prevented by FO administration that was initiated with either a 4- or 8-h TWE. Fish oil was ineffective after a 12-h TWE. Independent of the TWE, FO did not prevent ischemic neuronal death. In the hippocampus, but not cerebral cortex, TGCI-induced dendritic loss was prevented by FO with a 4-h TWE but not 12-h TWE. The level of docosahexaenoic acid almost doubled in the hippocampus in ischemic, FO-treated rats (4-h TWE). The data indicate that (i) the anti-amnesic effect of FO can be observed with a TWE of up to 8h, (ii) the stimulation of dendritic neuroplasticity may have contributed to this effect, and (iii) DHA in FO may be the main active constituent in FO that mediates the cognitive and neuroplasticity effects on TGCI.

Neuroprotective effects of Ilexonin A following transient focal cerebral ischemia in rats.

Ilexonin A is a compound isolated from the root of a plant commonly used in traditional Chinese medicine. The aim of the present study was to investigate the possible protective mechanism of Ilexonin A in rats subjected to occlusion of the middle cerebral artery (MCAO). Transient focal cerebral ischemia was induced by 2 h of MCAO, followed by reperfusion. Ilexonin A at doses of 20, 40 and 80 mg/kg were administered via intraperitoneal injection immediately following ischemia/reperfusion. The expression levels of glial fibrillary acidic protein (GFAP), ionized calcium­binding adapter molecule­1 (Iba­1), vascular endothelial growth factor (VEGF), fetal liver kinase­1 (Flk­1) and Nestin were examined using immunostaining and Western blot analysis of the peri­infarct region following ischemia/reperfusion. Ilexonin A significantly decreased the infarct volume and improved neurological deficits in a dose­dependent manner. The expression levels of VEGF, Flk­1 and Nestin were significantly increased in the rats treated with Ilexonin A, compared with the rats administered with saline. Following treatment with Ilexonin A, a higher number of GFAP­positive astrocytes were found in the Ilexonin A­treated rats at 1, 3 and 7 days, compared with the rats exposed to ischemia only, however, there were fewer astrocytes at 14 days, compared with the ischemia group. Ilexonin A significantly decreased the protein expression of Iba­1. The results of the present study suggested that the protective effects of Ilexonin A were associated with revascularization, neuronal regeneration, and the regulation of astrocyte and microglia cell activation.

Imaging mass spectrometry detects dynamic changes of phosphatidylcholine in rat hippocampal CA1 after transient global ischemia.

BACKGROUND AND PURPOSE: The initial steps in the cascade leading to cell death are still unknown because of the limitations of the existing methodology, strategy, and modalities used. METHODS: Imaging mass spectrometry (IMS) was used to measure dynamic molecular changes of phosphatidylcholine (PC) species in the rat hippocampus after transient global ischemia (TGI) for 6min. Fresh frozen sections were obtained after euthanizing the rats on Days 1, 2, 4, 7, 10, 14, and 21. Histopathology and IMS of adjacent sections compared morphological and molecular changes, respectively. RESULTS: Histopathological changes were absent immediately after TGI (at Day 1, superacute phase). At Days 2-21 after TGI (from subacute to chronic phases), histopathology revealed neuronal death associated with gliosis, inflammation, and accumulation of activated microglia in CA1. IMS detected significant molecular changes after TGI in the same CA1 domain: increase of PC (diacyl-16:0/22:6) in the superacute phase and increase of PC (diacyl-16:0/18:1) in the subacute to chronic phases. CONCLUSIONS: Histopathology and IMS can provide comprehensive and complementary information on cell death mechanisms in the hippocampal CA1 after global ischemia. IMS provided novel data on molecular changes in phospholipids immediately after TGI. Increased level of PC (diacyl-16:0/22:6) in the pyramidal cell layer of hippocampal CA1 prior to the histopathological change may represent an early step in delayed neuronal death mechanisms.

A novel dual-glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide receptor agonist is neuroprotective in transient focal cerebral ischemia in the rat.

Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) receptor agonists have been shown to be neuroprotective in previous studies in animal models of Alzheimer's or Parkinson's disease. Recently, novel dual-GLP-1/GIP receptor agonists that activate both receptors (DA) were developed to treat diabetes. We tested the protective effects of a novel potent DA against middle cerebral artery occlusion injury in rats and compared it with a potent GLP-1 analog, Val(8)-GLP-1(glu-PAL). Animals were evaluated for neurologic deficit score, infarct volume, and immunohistochemical analyses of the brain at several time points after ischemia. The Val(8)-GLP-1(glu-PAL)-treated and DA-treated groups showed significantly reduced scores of neurological dysfunction, cerebral infarction size, and percentage of TUNEL-positive apoptotic neurons. Furthermore, the expression of the apoptosis marker Bax, the inflammation marker iNOS, and the survival marker Bcl-2 was significantly increased. The DA-treated group was better protected against neurodegeneration than the Val(8)-GLP-1(glu-PAL) group, and the scores of neurological dysfunction, cerebral infarction size, and expression of Bcl-2 were higher, whereas the percentage of TUNEL-positive neurons and the levels of Bax and iNOS were lower in the DA group. DA treatment reduced the infarct volume and improved the functional deficit. It also suppressed the inflammatory response and cell apoptosis after reperfusion. In conclusion, the novel GIP and GLP-1 dual-receptor agonist is more neuroprotective than a GLP-1 receptor agonist in key biomarkers of neuronal degeneration.

Ginsenoside Rd promotes neurogenesis in rat brain after transient focal cerebral ischemia via activation of PI3K/Akt pathway.

AIM: To investigate the effects of ginsenoside Rd (Rd) on neurogenesis in rat brain after ischemia/reperfusion injury (IRI). METHODS: Male SD rats were subjected to transient middle cerebral artery occlusion (MCAO) followed by reperfusion. The rats were injected with Rd (1, 2.5, and 5 mg·kg(-1)·d(-1), ip) from d 1 to d 3 after MCAO, and with BrdU (50 mg·kg(-1)·d(-1), ip) from d 3 to d 6, then sacrificed on 7 d. The infarct size and neurological scores were assessed. Neurogenesis in the brains was detected by BrdU, DCX, Nestin, and GFAP immunohistochemistry staining. PC12 cells subjected to OGD/reperfusion were used as an in vitro model of brain ischemia. VEGF and BDNF levels were assessed with ELISA, and Akt and ERK phosphorylation was measured using Western blotting. RESULTS: Rd administration dose-dependently decreased the infarct size and neurological scores in the rats with IRI. The high dose of Rd 5 (mg·kg(-1)·d(-1)) significantly increased Akt phosphorylation in ipsilateral hemisphere, and markedly increased the number of BrdU/DCX and Nestin/GFAP double-positive cells in ischemic area, which was partially blocked by co-administration of the PI3 kinase inhibitor LY294002. Treatment with Rd (25, 50, and 100 µmol/L) during reperfusion significantly increased the expression of VEGF and BDNF in PC12 cells with IRI. Furthermore, treatment with Rd dose-dependently increased the phosphorylation of Akt and ERK, and significantly decreased PC12 cell apoptosis, which were blocked by co-application of LY294002. CONCLUSION: Rd not only attenuates ischemia/reperfusion injury in rat brain, but also promotes neurogenesis via increasing VEGF and BDNF expression and activating the PI3K/Akt and ERK1/2 pathways.

Neuroprotective effect of the hairy root extract of Angelica gigas NAKAI on transient focal cerebral ischemia in rats through the regulation of angiogenesis.

BACKGROUND: In this study, we investigated the neuroprotective effect of the hairy root extract of Angelica gigas NAKAI (Angelica Gigantis Radix) on transient focal cerebral ischemia in rats through the regulation of angiogenesis molecules. METHODS: Male Sprague-Dawley rats were induced focal cerebral ischemia by a transient middle cerebral artery occlusion (tMCAO) for 90 min, and then orally administrated with the water extract of A. gigas hairy roots (AG). After 24 h reperfusion, infarction volume and the changes of BBB permeability were measured by TTC and Evans Blue (EB) staining. The neuronal cell damage and the activation of glial cells were assessed by immunohistochemistry in the ischemic brain. The expression of angiogenesis-induced proteins such as angiopoietin-1 (Ang-1), and vascular endothelial growth factor (VEGF), inflammatory protein such as intercellular adhesion molecule-1 (CAM-1), tight junction proteins such as ZO-1, and Occludin and the phosphorylation of phosphatidylinositol 3-kinase (PI3K)/AKT were determined in the ischemic brains by Western blot, respectively. RESULTS: The treatment of AG extract significantly decreased the volumes of brain infarction, and edema in MACO-induced ischemic rats. AG extract decreased the increase of BBB permeability, and neuronal death and inhibited the activation of astrocytes and microglia in ischemic brains. AG extract also significantly increased the expression of Ang-1, Tie-2, VEGF, ZO-1 and Occludin through activation of the PI3K/Akt pathway. AG extract significantly increased the expression of ICAM-1 in ischemic brains. CONCLUSIONS: Our results indicate that the hairy root of AG has a neuroprotective effect in ischemic stroke.

Valeriana officinalis Extracts Ameliorate Neuronal Damage by Suppressing Lipid Peroxidation in the Gerbil Hippocampus Following Transient Cerebral Ischemia.

As a medicinal plant, the roots of Valeriana officinalis have been used as a sedative and tranquilizer. In the present study, we evaluated the neuroprotective effects of valerian root extracts (VE) on the hippocampal CA1 region of gerbils after 5 min of transient cerebral ischemia. Gerbils were administered VE orally once a day for 3 weeks, subjected to ischemia/reperfusion injury, and continued on VE for 3 weeks. The administration of 100 mg/kg VE (VE100 group) significantly reduced the ischemia-induced spontaneous motor hyperactivity 1 day after ischemia/reperfusion. Four days after ischemia/reperfusion, animals treated with VE showed abundant cresyl violet-positive neurons in the hippocampal CA1 region when compared to the vehicle or 25 mg/kg VE-treated groups. In addition, the VE treatment markedly decreased microglial activation in the hippocampal CA1 region 4 days after ischemia. Compared to the other groups, the VE100 group showed the lowest level of lipid peroxidation during the first 24 h after ischemia/reperfusion. In summary, the findings in this study suggest that pretreatment with VE has protective effects against ischemic injury in the hippocampal pyramidal neurons by decreasing microglial activation and lipid peroxidation.

Effect of Khat on apoptosis and related gene Smac/DIABLO expression in the cerebral cortex of rats following transient focal ischemia.

BACKGROUND: The leaves of the Khat shrub contain the major alkaloid compounds (cathinone) and cathine. These compounds can induce apoptosis and exacerbate the acute cerebral infarction, but the underlying mechanism is poorly understood. The present study aimed to investigate the effects of Khat treatment on the expression and cellular localization of Smac/Diablo (second mitochondrial activator of caspase) in the cortex of ischemic rat brain. METHODS: Adult male Sprague-Dawley rats were administered Khat (3g/kg) twice daily for 4 weeks, then underwent left middle cerebral artery occlusion (MCAO) for 2h and reperfusion for 3, 6 and 12h, respectively. The infarction area was evaluated with 2,3,5-triphenyltetrazolium chloride (TTC) staining. Apoptosis was assessed by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL). Smac/DIABLO expression levels in experimental and control groups were examined by immunohistochemistry and Western blot. RESULTS: Khat significantly exacerbates the neurological damage compared with control (p<0.05). In addition, Khat-treatment significantly increased the number of TUNEL-positive cells 3h (p<0.01) and 12h (p<0.05) after reperfusion. Ischemia/reperfusion enhanced the release of Smac/DIABLO from the mitochondria to the cytosol after reperfusion. Such release of Smac/DIABLO was elevated after the rats were pretreated with Khat. CONCLUSIONS: Our results indicate that Khat treatment can induce apoptosis through enhancing the release of Smac/DIABLO from the mitochondria to the cytosol after transient focal ischemia which may be an important mechanism of Khat neurotoxicity. Therefore, Khat chewing should be avoided by people who have cerebrovascular problems.

Acupuncture improves locomotor function by enhancing GABA receptor expression in transient focal cerebral ischemia rats.

Stroke is the major cause of long-term disability among adults. Recent studies have found that GABAergic inhibitory neurotransmission plays a vital role in ameliorate locomotor damage after ischemic injury. Acupuncture has been widely used to improve locomotor function. However, the underlying mechanisms remain unclear. The present study is designed to investigate whether GABA and GABA receptors are involved in the mechanism underlying acupuncture treatment in rats with middle cerebral artery occlusion (MCAO). One week after acupuncture at JiaJi acupoint, the locomotor function and infarct volumes were tested. Then level of GABA and the expressions of GABAAγ2 and GABABR2 were assessed by high-performance liquid chromatography, immunofluorescence and immunohistochemistry, respectively. Compared with normal group, GABAAγ2 and GABABR2 expressions were decreased in striatum and spinal cord of the MCAO group. After acupuncture, the expressions of the two receptors were increased, but levels of GABA and trafficking protein, kinesin binding 1 (TRAK1), which plays a role in the intracellular transport of GABA receptors, were unchanged. The present study suggests that acupuncture could reverse locomotor function by modulating the expressions of GABA receptors in MCAO rats.