Primary Cultures Of Rat Cortical Neurons Research Articles

Neurotrophic effects of 7,8-dihydroxycoumarin in primary cultured rat cortical neurons

Neuronal loss in the central nervous system is central to the occurrence of neurodegenerative diseases. Pharmaceutical companies have devoted much effort to developing new drugs against such diseases, since there are currently no effective drugs for neurodegenerative disease treatment. Promoting the capacity for nerve regeneration is an ideal treatment target. The present study aimed to investigate the neurotrophic effects of 7,8-dihydroxycoumarin (DHC) or daphnetin in primary cultured rat cortical neurons. Cortical neurons were identified by microtubule-associated protein 2 (MAP2) immunostaining. Morphological observation was used to measure the average length of neurite outgrowth. MTT and lactate dehydrogenase assays were used to assess neuronal survival. The mRNA expression of MAP2 and brain-derived neurotrophic factor (BDNF) was measured by RT-PCR. MAP2 immunostaining showed that most of the cultured cells were neurons. Compared with the vehicle control group, DHC promoted neurite outgrowth and prolonged neuronal survival time at concentrations ranging from 2 to 8 μmol/L. Expression of both BDNF mRNA and MAP2 mRNA was increased in the groups treated with 2, 4 and 8 μmol/L DHC. DHC significantly increases neurite outgrowth and promotes neuronal survival in primary cultured rat cortical neurons. The neurotrophic effects of DHC are probably associated with increased BDNF expression.

High level over-expression of different NCX isoforms in HEK293 cell lines and primary neuronal cultures is protective following oxygen glucose deprivation

In this study we have assessed sodium–calcium exchanger (NCX) protein over-expression on cell viability in primary rat cortical neuronal and HEK293 cell cultures when subjected to oxygen–glucose deprivation (OGD). In cortical neuronal cultures, NCX2 and NCX3 over-expression was achieved using adenoviral vectors, and following OGD increased neuronal survival from ≈20% for control vector treated cultures to ≈80% for both NCX isoforms. In addition, we demonstrated that NCX2 and NCX3 over-expression in cortical neuronal cultures enables neurons to maintain intracellular calcium at significantly lower levels than control vector treated cultures when exposed to high (9mM) extracellular calcium challenge. Further assessment of NCX activity during OGD was performed using HEK293 cell lines generated to over-express NCX1, NCX2 or NCX3 isoforms. While it was shown that NCX isoform expression differed considerably in the different HEK293 cell lines, high levels of NCX over-expression was associated with increased resistance to OGD. Taken together, our findings show that high levels of NCX over-expression increases neuronal and HEK293 cell survival following OGD, improves calcium management in neuronal cultures and provides additional support for NCX as a therapeutic target to reduce ischemic brain injury.

Phenylbutenoid dimers isolated from Zingiber purpureum exert neurotrophic effects on cultured neurons and enhance hippocampal neurogenesis in olfactory bulbectomized mice

Trans-3-(3′4′-dimethoxyphenyl)-4-[(E)-3″,4″-dimethoxystyryl]cyclohex-1-ene (Comp.1) and cis-3-(3′4′-dimethoxyphenyl)-4-[(E)-3″,4″-dimethoxystyryl]cyclohex-1-ene (Comp.2), phenylbutenoid dimers, have been isolated as neurotrophic molecules from an Indonesian medicinal plant, Zingiber purpureum. The aim of this study was to explore the neurotrophic effects of Comp.1 and Comp.2 in vitro and in vivo. Comp.1 (10–30μM) or Comp.2 (30μM) significantly induced neurite sprouting in PC12 cells. Comp.1 (0.03–3μM) or Comp.2 (0.3–3μM) significantly increased the neurite length and number of neurites in primary cultured rat cortical neurons. Comp.1 (30μM) and Comp.2 (3–30μM) also provided significant protection against cell death caused by deprivation of serum. The in vivo effects of both Comp.1 and Comp.2 were evaluated on hippocampal neurogenesis in olfactory bulbectomized (OBX) mice, an experimental depression and dementia animal model. Comp.1 (50mg/kg p.o.), Comp.2 (50mg/kg p.o.), or fluoxetine (10mg/kg i.p.), an antidepressant, were administrated once a day on days 15–28 after OBX. Neurogenesis was assessed by analysis of cells expressing NeuN, a neuronal marker, and 5-bromo-2′-deoxyuridine (BrdU) uptake. Immunohistochemical analysis showed that the number of BrdU/NeuN double-labeled cells in the dentate gyrus was significantly decreased 30 days after OBX. Chronic treatment with Comp.1, Comp.2 or fluoxetine significantly increased the number of BrdU/NeuN double-labeled cells. These results indicate that Comp.1 and Comp.2 have neurotrophic effects, and have the potential for disease modification in depression and dementia.

Hypoxia enhances high-voltage-activated calcium currents in rat primary cortical neurons via calcineurin

Hypoxia regulates neuronal ion channels, sometimes resulting in seizures. We evaluated the effects of brief sustained hypoxia (1% O(2), 4h) on voltage-gated calcium channels (VGCCs) in cultured rat primary cortical neurons. High-voltage activated (HVA) Ca(2+) currents were acquired immediately after hypoxic exposure or after 48h recovery in 95% air/5% CO(2). Maximal Ca(2+) current density increased 1.5-fold immediately after hypoxia, but reverted to baseline after 48h normoxia. This enhancement was primarily due to an increase in L-type VGCC activity, since nimodipine-insensitive residual Ca(2+) currents were unchanged. The half-maximal potentials of activation and steady-state inactivation were unchanged. The calcineurin inhibitors FK-506 (in the recording pipette) or cyclosporine A (during hypoxia) prevented the post-hypoxic increase in HVA Ca(2+) currents, while rapamycin and okadaic acid did not. L-type VGCCs were the source of Ca(2+) for calcineurin activation, as nimodipine during hypoxia prevented post-hypoxic enhancement. Hypoxia transiently potentiated L-type VGCC currents via calcineurin, suggesting a positive feedback loop to amplify neuronal calcium signaling that may contribute to seizure generation.

The first examples of seco-prezizaane-type norsesquiterpenoids with neurotrophic activity from Illicium jiadifengpi

Two seco-prezizaane-type sesquiterpenoids (2R)-hydroxy-norneomajucin (1) and jiadifenone (2) that represent the first examples of nor-type were isolated from the methanol extract of the pericarps of Illicium jiadifengpi. Their structures and the absolute configuration of 1 were established by the analysis of spectroscopic data and chemical conversion of (2S)-hydroxyneomajucin to 1, respectively. In addition, compound 1 exhibited neurotrophic activity to significantly promote neurite outgrowth in the primary cultured rat cortical neurons at concentrations ranging from 1 to 10μmolL−1.

ChemInform Abstract: New Prenylated C6—C3 Compounds from the Twigs of Illicium anisatum.

AbstractThe new compound (I), named cycloillicinone, is isolated together with the new compound (II) which shows moderate neurite‐outgrowth promoting activity in primary cultured rat cortical neurons at a concentration of 10 μM.

Protective effects of lycopene against amyloid β-induced neurotoxicity in cultured rat cortical neurons

The neurotoxicity of amyloid β (Aβ) has been implicated as a critical cause in the pathogenesis of Alzheimer's disease (AD). Among antioxidant phytochemicals derived from fruit and vegetables, lycopene has recently received considerable attention for its potent protective properties already demonstrated in several models of oxidative damage. The present study aims to investigate whether lycopene could provide protective effects against Aβ-induced neurotoxicity in primary cultured rat cortical neurons. The cultured cortical neurons were pretreated with different dose of lycopene for 4h, followed by the challenge with 25μM Aβ25–35 for 24h. The results showed that pretreatment with lycopene efficiently attenuated Aβ25–35-induced neurotoxicity, as evidenced by the improved cell viability and the decreased apoptotic rate. In addition, lycopene inhibited the reactive oxygen species generation and mitochondrial membrane potential depolarization caused by Aβ25–35. Lycopene also restored the levels of proapoptotic Bax, antiapoptotic Bcl-2, and inhibited caspase-3 activation. These beneficial effects may contribute to the protection against Aβ-induced neurotoxicity. Together, our results suggest that the natural antioxidant lycopene has potential for neuroprotection and therefore, may be a promising candidate for AD treatment.

Mitochondrial ERK plays a key role in delta-opioid receptor neuroprotection against acute mitochondrial dysfunction

It is well established that stimulating delta-opioid receptor (DOR) with its specific agonists elicits neuroprotection against hypoxia/ischemia. Mitochondrial dysfunction plays a key role in hypoxic neuronal injury, but the effects of DOR activation on mitochondrial dysfunction in neurons are poorly elucidated. In this investigation, we studied the effects of [ d-Ala2, d-Leu5] enkephalin (DADLE), a potent DOR agonist, on acute mitochondrial dysfunction and ensuing cell damage induced by sodium azide in primary rat cortical neuronal cultures, and explored possible mechanisms underlying. Here, we show that DADLE reverses NaN 3-induced acute mitochondrial dysfunction by selectively activating DOR, mainly including mitochondrial membrane depolarization, mitochondrial Ca 2+ overload and reactive oxygen species generation. DOR stimulation also inhibits cytochrome c release and caspase-3 activation, and attenuates neuronal death caused by acute NaN 3 insults. Furthermore, DOR activation with DADLE protects neurons from acute NaN 3 insults mainly through PKC–ERK pathway, and mitochondrial ERK activation is especially required for DOR neuroprotection against acute mitochondrial dysfunction.

Isoliquiritigenin is a novel NMDA receptor antagonist in kampo medicine yokukansan.

Effects of a traditional Japanese medicine, yokukansan, which is composed of seven medicinal herbs, on glutamate-induced cell death were examined using primary cultured rat cortical neurons. Yokukansan (10-300 μg/ml) inhibited the 100 μM glutamate-induced neuronal death in a concentration-dependent manner. Among seven constituent herbs, higher potency of protection was found in Uncaria thorn (UT) and Glycyrrhiza root (GR). A similar neuroprotective effect was found in four components (geissoschizine methyl ether, hirsuteine, hirsutine, and rhynchophylline) in UT and four components (glycycoumarin, isoliquiritigenin, liquiritin, and 18β-glycyrrhetinic acid) in GR. In the NMDA receptor binding and receptor-linked Ca(2+) influx assays, only isoliquiritigenin bound to NMDA receptors and inhibited the glutamate-induced increase in Ca(2+) influx. Glycycoumarin and 18β-glycyrrhetinic acid bound to NMDA receptors, but did not inhibit the Ca(2+) influx. The four UT-derived components did not bind to NMDA receptors. The present results suggest that neuroprotective components (isoliquiritigenin, glycycoumarin, liquiritin, and 18β-glycyrrhetinic acid in GR and geissoschizine methyl ether, hirsuteine, hirsutine, and rhynchophylline in UT) are contained in yokukansan, and isoliquiritigenin, which is one of them, is a novel NMDA receptor antagonist.

Polynitroxylated pegylated hemoglobin: A novel neuroprotective hemoglobin for acute volume-limited fluid resuscitation after combined traumatic brain injury and hemorrhagic hypotension in mice*

Resuscitation of hemorrhagic hypotension after traumatic brain injury is challenging. A hemoglobin-based oxygen carrier may offer advantages. The novel therapeutic hemoglobin-based oxygen carrier, polynitroxylated pegylated hemoglobin (PNPH), may represent a neuroprotective hemoglobin-based oxygen carrier for traumatic brain injury resuscitation. 1) PNPH is a unique non-neurotoxic hemoglobin-based oxygen carrier in neuronal culture and is neuroprotective in in vitro neuronal injury models. 2) Resuscitation with PNPH would require less volume to restore mean arterial blood pressure than lactated Ringer's or Hextend and confer neuroprotection in a mouse model of traumatic brain injury plus hemorrhagic hypotension. Prospective randomized, controlled experimental study. University center. In rat primary cortical neuron cultures, control bovine hemoglobin was neurotoxic (lactate dehydrogenase release; 3-[4,5-dimethylthiazol-2-yl-]-2,5-diphenyltetrazolium bromide assay) at concentrations from 12.5 to 0.625 μM, whereas polyethylene glycol-conjugated hemoglobin showed intermediate toxicity. PNPH was not neurotoxic (p<.05 vs. bovine hemoglobin and polyethylene glycol hemoglobin; all concentrations). PNPH conferred neuroprotection in in vitro neuronal injury (glutamate/glycine exposure and neuronal stretch), as assessed via lactate dehydrogenase and 3-[4,5-dimethylthiazol-2-yl-]-2,5-diphenyltetrazolium bromide (all p<.05 vs. control). C57BL6 mice received controlled cortical impact followed by hemorrhagic hypotension (2 mL/100 g, mean arterial blood pressure ∼35-40 mm Hg) for 90 min. Mice were resuscitated (mean arterial blood pressure>50 mm Hg for 30 min) with lactated Ringer's, Hextend, or PNPH, and then shed blood was reinfused. Mean arterial blood pressures, resuscitation volumes, blood gasses, glucose, and lactate were recorded. Brain sections at 7 days were examined via hematoxylin and eosin and Fluoro-Jade C (identifying dying neurons) staining in CA1 and CA3 hippocampus. Resuscitation with PNPH or Hextend required less volume than lactated Ringer's (both p<.05). PNPH but not Hextend improved mean arterial blood pressure vs. lactated Ringer's (p<.05). Mice resuscitated with PNPH had fewer Fluoro-Jade C positive neurons in CA1 vs. Hextend and lactated Ringer's, and CA3 vs. Hextend (p<.05). PNPH is a novel neuroprotective hemoglobin-based oxygen carrier in vitro and in vivo that may offer unique advantages for traumatic brain injury resuscitation.

Gadolinium‐induced oxidative stress triggers endoplasmic reticulum stress in rat cortical neurons

Introduction of Gadolinium (Gd) to the nervous system is linked to the development of neurotoxicity involving both oxidative and endoplasmic reticulum (ER) stress. Gd levels (0.2-20 μm) in the form of gadolinium trichloride (GdCl(3)) cause neurotoxicity in vitro. We investigated the signaling pathways in primary cultured rat cortical neurons and tested whether GdCl(3) induced oxidative and ER stress. Results showed that Gd-induced neural cell death followed a rapid accumulation of intracellular reactive oxygen species. In addition, Gd exposure resulted in spliced X-box binding protein 1 mRNA and increased expression of binding immunoglobulin protein, thus activating transcription factor 4 (ATF4), ATF6, and C/EBP homologous protein mRNA. Up-regulated expression of binding immunoglobulin protein is a hallmark of ER stress and C/EBP homologous protein is an ER stress-related pro-apoptotic transcription factor. Activation of ER stress downstream substrates, inositol-requiring kinase 1 and ATF6, was also observed in Gd-treated cells. The neurotoxic effects of Gd were blocked by the antioxidant N-acetylcysteine. Results demonstrated that Gd-induced cytotoxicity in neurons occurs via oxidative injury and ER stress-related signal transduction, thus offering new insight into the neurotoxicology of gadolinium.

New Prenylated C6-C3 Compounds from the Twigs of Illicium anisatum

Two new prenylated C₆-C₃ compounds, cycloillicinone (1) and 4-allyl-2-methoxy-6-(2-methylbut-3-en-2-yl)phenol (2), were isolated from the twigs of Illicium anisatum, and their structures were determined by 2D-NMR methods. Cycloillicinone (1) is a unique prenylated C₆-C₃ that is appended with an additional geranyl unit. Compound 2 was found to show moderate neurite-outgrowth promoting activity in primary cultured rat cortical neurons at a concentration of 10 µM.

A Strong Protective Action of Guttiferone-A, a Naturally Occurring Prenylated Benzophenone, Against Iron-Induced Neuronal Cell Damage

Guttiferone-A (GA) is a natural occurring polyisoprenylated benzophenone with several reported pharmacological actions. We have assessed the protective action of GA on iron-induced neuronal cell damage by employing the PC12 cell line and primary culture of rat cortical neurons (PCRCN). A strong protection by GA, assessed by the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carbox-anilide (XTT) assay, was revealed, with IC(50) values <1 µM. GA also inhibited Fe(3+)-ascorbate reduction, iron-induced oxidative degradation of 2-deoxiribose, and iron-induced lipid peroxidation in rat brain homogenate, as well as stimulated oxygen consumption by Fe(2+) autoxidation. Absorption spectra and cyclic voltammograms of GA-Fe(2+)/Fe(3+) complexes suggest the formation of a transient charge transfer complex between Fe(2+) and GA, accelerating Fe(2+) oxidation. The more stable Fe(3+) complex with GA would be unable to participate in Fenton-Haber Weiss-type reactions and the propagation phase of lipid peroxidation. The results show a potential of GA against neuronal diseases associated with iron-induced oxidative stress.

Nucleocytoplasmic Shuttling of Dysbindin-1, a Schizophrenia-related Protein, Regulates Synapsin I Expression

Dysbindin-1 is a 50-kDa coiled-coil-containing protein encoded by the gene DTNBP1 (dystrobrevin-binding protein 1), a candidate genetic factor for schizophrenia. Genetic variations in this gene confer a susceptibility to schizophrenia through a decreased expression of dysbindin-1. It was reported that dysbindin-1 regulates the expression of presynaptic proteins and the release of neurotransmitters. However, the precise functions of dysbindin-1 are largely unknown. Here, we show that dysbindin-1 is a novel nucleocytoplasmic shuttling protein and translocated to the nucleus upon treatment with leptomycin B, an inhibitor of exportin-1/CRM1-mediated nuclear export. Dysbindin-1 harbors a functional nuclear export signal necessary for its nuclear export, and the nucleocytoplasmic shuttling of dysbindin-1 affects its regulation of synapsin I expression. In brains of sandy mice, a dysbindin-1-null strain that displays abnormal behaviors related to schizophrenia, the protein and mRNA levels of synapsin I are decreased. These findings demonstrate that the nucleocytoplasmic shuttling of dysbindin-1 regulates synapsin I expression and thus may be involved in the pathogenesis of schizophrenia.

Neuroprotective effects of water-soluble Ganoderma lucidum polysaccharides on cerebral ischemic injury in rats

Aim of the study To investigate the neuroprotective effects of water-soluble Ganoderma lucidum polysaccharides (GLPS) on cerebral ischemic injury in rats, and to explore the involved mechanisms. Materials and methods Two models [middle cerebral artery occlusion (MCAO) in Sprague–Dawley (SD) rats and oxygen and glucose deprivation (OGD) in primary cultured rat cortical neurons] were employed to mimic ischemia–reperfusion (I/R) damage, in vivo and in vitro, respectively. Cerebral infarct area was measured by tetrazolium staining, and neurological functional deficits were assessed at 24 h after I/R. Neuronal apoptosis was studied by Nissl staining and DNA fragmentation assay. Neuronal injury was assessed by morphological examination using phase-contrast microscopy and quantified by measuring the amount of lactate dehydrogenase (LDH) leakage, cell viability was measured by sodium 3′-1- (phenylaminocarbonyl)-3, 4-tetrazolium-bis (4-methoxy-6-nitro) benzene sulfonic acid (XTT) reduction. Neuronal apoptosis was determined by flow cytometry, and electron microscopy was used to study morphological changes of neurons. Caspase-3, -8 and -9 activation and Bcl-2, Bax protein expression were determined by western blot analysis. Results Oral administration of GLPS (100, 200 and 400 mg/kg) significantly reduced cerebral infarct area, attenuated neurological functional deficits, and reduced neuronal apoptosis in ischemic cortex. In OGD model, GLSP (0.1, 1 and 10 μg/ml) effectively reduced neuronal cell death and relieved cell injury. Moreover, GLPS decreased the percentage of apoptotic neurons, relieved neuronal morphological damage, suppressed overexpression of active caspases-3, -8 and -9 and Bax, and inhibited the reduction of Bcl-2 expression. Conclusions Our findings indicate that GLPS protects against cerebral ischemic injury by inhibiting apoptosis by downregulating caspase-3 activation and modulating the Bcl-2/Bax ratio.

Evaluation of Samjunghwan, a traditional medicine, for neuroprotection against damage by amyloid-beta in rat cortical neurons

Aim of the study Samjunghwan (SJH) is a multi-herbal traditional medicine composed of Mori Fructus, Lycii Radicis Cortex, and Atractylodis Rhizoma Alba and it is clinically applied as an anti-aging agent in neurodegenerative disorders, to promote longevity. In the present study, we evaluated the neuroprotective effect of SJH in Alzheimer's disease induced by amyloid-beta (Abeta) and examined the related pathways. Materials and methods To evaluate the protective effect of SJH, we conducted thiazolyl blue tetrazolium bromide, lactate dehydrogenase, and MAP-2 staining assays of primary cultured rat cortical neurons stressed by Abeta 25–35. To investigate the possible mechanism of action, we examined the Bcl-2/Bax expression ratio, mitochondrial membrane potential (Δ ψ M ), cytochrome C release, and caspase-3 activation, focusing on the mitochondria-mediated apoptotic pathways. Results SJH at concentrations of 10 and 100 μg/ml provided significant protection of rat cortical neurons from Abeta 25–35 neurotoxicity. At the maximum effective dose of 100 μg/ml, SJH significantly increased the anti-apoptotic protein (Bcl-2)/pro-apoptotic protein (Bax) ratio and inhibited Δ ψ M depolarization, cytosolic cytochrome C release, and caspase-3 activation. Conclusion SJH appears to provide neuroprotection against mitochondria-mediated apoptotic pathways in this Abeta 25–35-induced Alzheimer's disease model.

Neuroprotective Effects of Hydroxysafflor Yellow A Against Excitotoxic Neuronal Death Partially Through Down-Regulation of NR2B-Containing NMDA Receptors

Hydroxysafflor yellow A (HSYA) is a component of the flower Carthamus tinctorius L. that elicits neuroprotective effects in vivo and in vitro. The purpose of this study was to investigate pharmacological properties of HSYA on neurotoxicity of glutamate in primary cultured rat cortical neurons along with its possible mechanism of action. After challenge with N-methyl-d-aspartate (NMDA, 100 microM) for 30 min, loss of cell viability and excessive apoptotic cell death were observed in cultured cortical neurons. However, the excitotoxic neuronal death was attenuated markedly by HSYA treatment. Western blot analysis revealed that HSYA decreased expression of Bax and rescued the balance of pro-and anti-apoptotic proteins. In addition, HSYA significantly reversed up-regulation of NR2B-containing NMDA receptors by exposure to NMDA, while it did not affect the expression of NR2A-containing NMDA receptors. These finding suggest that HSYA protects cortical neurons, at least partially, from inhibiting the expression NR2B-containing NMDA receptors and by regulating Bcl-2 family.

Chitooligosaccharides protect rat cortical neurons against copper induced damage by attenuating intracellular level of reactive oxygen species

A large number of evidence has suggests that dyshomeostasis of the redox-active biometals such as copper and other metal ions can lead to oxidative stress in neurons, which plays a key role in the pathology of neurodegenerative disorders. Chitooligosaccharides (COSs) are biodegradation product of chitosan and demonstrated diverse biological activities, Here we first report that protective effects of COSs (M.W. 1500, DD. 90%) against Cu(II) induced neurotoxicity in primary cultured rat cortical neurons. The toxicity of Cu(II) to cortical neurons was obviously attenuated in a concentration-dependent manner by COSs pretreated. The data derived from lactate dehydrogenase (LDH) release and the Hoechst 33342 assay support the results from MTT assay. After DCFH assay, COSs were found to depress Cu(II) induced elevation in intracellular reactive oxygen species (ROS), These findings suggest that COSs protect against Cu(II) induced neurotoxicity in primary cortical neurons by interfering with an increase in intracellular reactive oxygen species (ROS).

The Recombinant Amyloid-β Peptide Aβ1–42 Aggregates Faster and Is More Neurotoxic than Synthetic Aβ1–42

Aggregation of the amyloid-β (Aβ) peptide is considered a central event in the pathogenesis of Alzheimer's disease (AD). In order to bypass methodological bias related to a variety of impurities commonly present in typical preparations of synthetic Aβ, we developed a simple, generally applicable method for recombinant production of human Aβ and Aβ variants in Escherichia coli that provides milligram quantities of Aβ in very high purity and yield. Amyloid fibril formation in vitro by human Aβ1–42, the key amyloidogenic Aβ species in AD, was completed threefold faster with recombinant Aβ1–42 compared to synthetic preparations. In addition, recombinant Aβ1–42 was significantly more toxic to cultured rat primary cortical neurons, and it was more toxic in vivo, as shown by strongly increased induction of abnormal phosphorylation of tau and tau aggregation into neurofibrillary tangles in brains of P301L tau transgenic mice. We conclude that even small amounts of impurities in synthetic Aβ—including a significant fraction of racemized peptides that cannot be avoided due to the technical limitations of peptide synthesis—prevent or slow Aβ incorporation into the regular quaternary structure of growing β-amyloid fibrils. The results validate the use of recombinant Aβ1–42 for both in vitro and in vivo studies addressing the mechanisms underlying Aβ aggregation and its related biological consequences for the pathophysiology, therapy, and prevention of AD.

Rosuvastatin induces delayed preconditioning against l-glutamate excitotoxicity in cultured cortical neurons

We tested whether rosuvastatin (RST) protected against excitotoxic neuronal cell death in rat primary cortical neuronal cultures. l-Glutamate (200 μM, 1 h) reduced neuronal viability (% of naive controls, mean ± SEM, n = 8–32, * p < 0.05) from 100 ± 2% to 60 ± 1%*, but pretreatment with RST (0.5 μM, 3 days) increased survival to 88 ± 2%*. RST-induced neuroprotection was not affected by co-application with mevalonate (10 μM), although the same dose of mevalonate fully prevented the neurotoxic effects of a high dose (20 μM) of RST. RST (0.5 μM) pretreatment did not affect mitochondrial membrane potential or superoxide anion levels in quiescent neurons. However, RST pretreatment blunted elevations in free intracellular Ca 2+ and reduced increases in superoxide anion levels following glutamate exposure. Manganese superoxide dismutase (SOD), copper–zinc SOD, catalase, and reduced glutathione levels were unaffected by RST pretreatment. In contrast, acute, one time RST application did not affect either baseline or l-glutamate-induced increases in superoxide levels. In summary, three-day RST pretreatment induces resistance to the excitotoxic effect of l-glutamate in cultured neurons apparently by a mechanism that is independent of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibition. The delayed neuroprotection by RST against excitotoxicity does not involve sustained mitochondrial depolarization or superoxide anion production as initiating events, although it is associated with reduced Ca 2+ influx and superoxide anion production upon l-glutamate challenge.