LRP4-related signalling pathways and their regulatory role in neurological diseases.

The mechanism of action of low-density lipoprotein receptor related protein 4 (LRP4) is mediated largely via the Agrin-LRP4-MuSK signalling pathway in the nervous system. LRP4 contributes to the development of synapses in the peripheral nervous system (PNS). It interacts with signalling molecules such as the amyloid beta-protein precursor (APP) and the wingless type protein (Wnt). Its mechanisms of action are complex and mediated via interaction between the pre-synaptic motor neuron and post-synaptic muscle cell in the PNS, which enhances the development of the neuromuscular junction (NMJ). LRP4 may function differently in the central nervous system (CNS) than in the PNS, where it regulates ATP and glutamate release via astrocytes. It mayaffect the growth and development of the CNS by controlling the energy metabolism. LRP4 interacts with Agrin to maintain dendrite growth and density in the CNS. The goal of this article is to review the current studies involving relevant LRP4 signaling pathways in the nervous system. The review also discusses the clinical and etiological roles of LRP4 in neurological illnesses, such as myasthenia gravis, Alzheimer's disease and epilepsy. In this review, we provide a theoretical foundation for the pathogenesis and therapeutic application of LRP4 in neurologic diseases.

ULK1 confers neuroprotection by regulating microglial/macrophages activation after ischemic stroke.

Microglial activation and autophagy play a critical role in the progression of ischemic stroke and contribute to the regulation of neuroinflammation. Unc-51-like kinase 1 (ULK1) is the primary autophagy kinase involved in autophagosome formation. However, the impact of ULK1 on neuroprotection and microglial activation after ischemic stroke remains unclear. In this study, we established a photothrombotic stroke model, and administered SBI-0206965 (SBI), an ULK1 inhibitor, and LYN-1604 hydrochloride (LYN), an ULK1 agonist, to modulate ULK1 activity in vivo. We assessed sensorimotor deficits, neuronal apoptosis, and microglial/macrophage activation to evaluate the neurofunctional outcome. Immunofluorescence results revealed ULK1 was primarily localized in the microglia of the infarct area following ischemia. Upregulating ULK1 through LYN treatment significantly reduced infarct volume, improved motor function, promoted the increase of anti-inflammatory microglia. In conclusion, ULK1 facilitated neuronal repair and promoted the formation of anti-inflammatory microglia pathway after ischemic injury.

Laquinimod Inhibits Microglial Activation, Astrogliosis, BBB Damage, and Infarction and Improves Neurological Damage after Ischemic Stroke.

Glial activation is involved in neuroinflammation and blood-brain barrier (BBB) damage, which plays a key role in ischemic stroke-induced neuronal damage; therefore, regulating glial activation is an important way to inhibit ischemic brain injury. Effects of laquinimod (LAQ) include inhibiting axonal damage and neuroinflammation in multiple neuronal injury diseases. However, whether laquinimod can exert neuroprotective effects after ischemic stroke remains unknown. In this study, we investigated the effect of LAQ on glial activation, BBB damage, and neuronal damage in an ischemic stroke model. Adult ICR mice were used to create a photothrombotic stroke (PT) model. LAQ was administered orally at 30 min after ischemic injury. Neurobehavioral tests, Evans Blue, immunofluorescence, TUNEL, Nissl staining, and western blot were performed to evaluate the neurofunctional outcome. Quantification of immunofluorescence was evaluated by unbiased stereology. LAQ post-treatment significantly reduced infarction and improved forepaw function at 5 days after PT. Interestingly, LAQ treatment significantly promoted anti-inflammatory microglial activation. Moreover, LAQ treatment reduced astrocyte activation, glial scar formation, and BBB breakdown in ischemic brains. Therefore, this study demonstrated that LAQ post-treatment restricted microglial polarization, astrogliosis, and glial scar and improved BBB damage and behavioral function. LAQ may serve as a novel target to develop new therapeutic agents for ischemic stroke.

Neuregulin-1/PI3K signaling effects on oligodendrocyte proliferation, remyelination and behaviors deficit in a male mouse model of ischemic stroke.

In this study, we investigated the effect of neuregulin-1 (NRG1) on demyelination and neurological function in an ischemic stroke model, and further explored its neuroprotective mechanisms. Adult male ICR mice underwent photothrombotic ischemia surgery and were injected with NRG1 beginning 30 min after ischemia. Cylinder and grid walking tests were performed to evaluate the forepaw function. In addition, the effect of NRG1 on neuronal damage/death (Cresyl violet, CV), neuronal nuclei (NeuN), nestin, doublecortin (DCX), myelin basic protein (MBP), non-phosphorylated neurofilaments (SMI-32), adenomatous polyposis coli (APC), erythroblastic leukemia viral oncogene homolog (ErbB) 2, 4 and serine-threonine protein kinase (Akt) in cortex were evaluated using immunohistochemistry, immunofluorescence and western blot. The cylinder and grid walking tests exposed that treatment of NRG1 observably regained the forepaw function. NRG1 treatment reduced cerebral infarction, restored forepaw function, promoted proliferation and differentiation of neuron and increased oligodendrogliogenesis. The neuroprotective effect of NRG1 is involved in its activation of PI3K/Akt signaling pathway via ErbB2, as shown by the suppression of the effect of NRG1 by the PI3K inhibitor LY294002. Our results demonstrate that NRG1 is effective in ameliorating the both acute phase neuroprotection and long-term neurological functions via resumption of neuronal proliferation and differentiation and oligodendrogliogenesis in a male mouse model of ischemic stroke.

Differences in TNF­α and TNF­R1 expression in damaged neurons and activated astrocytes of the hippocampal CA1 region between young and adult gerbils following transient forebrain ischemia.

Tumor necrosis factor (TNF)­α and TNF receptor 1 (TNF­R1) play diverse roles in modulating the neuronal damage induced by cerebral ischemia. The present study compared the time­dependent changes of TNF­α and TNF­R1 protein expression levels in the hippocampal subfield cornu ammonis 1 (CA1) between adult and young gerbils following transient forebrain ischemia (tFI), via western blot and immunohistochemistry analyses. In adult gerbils, delayed neuronal death of pyramidal neurons, the principal neurons in CA1, was recorded 4 days after tFI; however, in young gerbils, delayed neuronal death was recorded 7 days after tFI. TNF­α protein expression levels gradually increased in both groups following tFI; however, TNF­α expression was higher in young gerbils compared with adult gerbils. TNF­R1 protein expression levels markedly increased in both groups 1 day after tFI. Subsequently, TNF­R1 expression gradually decreased in young gerbils, whereas TNF­R1 expression levels were irregularly altered in adult gerbils following tFI. Notably, TNF­α immunoreactivity significantly increased in pyramidal neurons in both groups 1 day after tFI; however, the patterns altered between both groups. In adult gerbils, TNF­α immunoreactivity was rarely exhibited in pyramidal neurons 4 days after tFI due to neuronal death, suggesting that TNF­α immunoreactivity was newly expressed in astrocytes. In young gerbils, TNF­α immunoreactivity increased in pyramidal neurons 4 days after tFI, and TNF­α immunoreactivity was newly expressed in astrocytes. In addition, TNF­R1 immunoreactivity was exhibited in pyramidal cells of both sham groups, and significantly increased 1 day after tFI; however, the patterns altered between both groups. In adult gerbils, TNF­R1 immunoreactivity was rarely exhibited 4 days after tFI, and astrocytes newly expressed TNF­R1 immunoreactivity. In young gerbils, TNF­R1 immunoreactivity increased in pyramidal neurons 4 days after tFI; however, TNF­R1 immunoreactivity was not reported in pyramidal neurons and astrocytes thereafter. Taken together, the results of the present study suggest that different expression levels of TNF­α and TNF­R1 in ischemic CA1 between adult and young gerbils may be due to age­dependent differences of tFI­induced neuronal death.

Comparison of age-dependent alterations in thioredoxin 2 and thioredoxin reductase 2 expressions in hippocampi between mice and rats.

BACKGROUND: Aging is one of major causes triggering neurophysiological changes in many brain substructures, including the hippocampus, which has a major role in learning and memory. Thioredoxin (Trx) is a class of small redox proteins. Among the Trx family, Trx2 plays an important role in the regulation of mitochondrial membrane potential and is controlled by TrxR2. Hitherto, age-dependent alterations in Trx2 and TrxR2 in aged hippocampi have been poorly investigated. Therefore, the aim of this study was to examine changes in Trx2 and TrxR2 in mouse and rat hippocampi by age and to compare their differences between mice and rats. RESULTS: Trx2 and TrxR2 levels using Western blots in mice were the highest at young age and gradually reduced with time, showing that no significant differences in the levels were found between the two subfields. In rats, however, their expression levels were the lowest at young age and gradually increased with time. Nevertheless, there were no differences in cellular distribution and morphology in their hippocampi when it was observed by cresyl violet staining. In addition, both Trx2 and TrxR2 immunoreactivities in the CA1-3 fields were mainly shown in pyramidal cells (principal cells), showing that their immunoreactivities were altered like changes in their protein levels. CONCLUSIONS: Our current findings suggest that Trx2 and TrxR2 expressions in the brain may be different according to brain regions, age and species. Therefore, further studies are needed to examine the reasons of the differences of Trx2 and TrxR2 expressions in the hippocampus between mice and rats.

Dexmedetomidine protects against lung injury induced by limb ischemia-reperfusion via the TLR4/MyD88/NF-κB pathway.

Dexmedetomidine (DEX) can protect the lung from ischemia-reperfusion (I/R) injury, but the underlying mechanisms are not fully understood. The aims of this study were to determine whether DEX attenuates lung injury following lower extremity I/R and to investigate the related toll-like receptor 4 (TLR4) signaling pathway. Twenty-eight SD rats were divided into four groups (n = 7): Sham, I/R, I/R + DEX (25 µg/kg prior to ischemia), and I/R + DEX + Atip (250 µg/kg atipamezole before DEX treatment). Lower extremity I/R was induced by left femoral artery clamping for 3 hours and followed by 2 hours reperfusion. Quantitative alveolar damage and the wet/dry (W/D) ratio were calculated. Interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF)-α in the bronchoalveolar lavage fluid (BALF) and serum and myeloperoxidase (MPO) in the lung were measured. The TLR4 and MyD88 mRNA expression levels were measured by RT-PCR, nuclear factor (NF)-κB, and phosphorylated NF-κB by western blot, respectively. Quantitative alveolar damage, W/D ratio, MPO, BALF and serum IL-1, IL-6, and TNF-α, and TLR4, MyD88, NF-κB, and p-NF-κB expression significantly increased in the I/R group relative to the Sham group. DEX preconditioning significantly reduced lung edema, and histological injury relative to the I/R group. Serum and BALF IL-1, IL-6, and TNF-α levels, MPO activity and TLR4, MyD88, NF-κB, and p-NF-κB expression were also significantly reduced in the I/R + DEX group compared with the I/R group. Atipamezole partially reversed all the aforementioned effects. DEX preconditioning protects the lungs against lower extremity I/R injury via α2-adrenoceptor-dependent and α2-adrenoceptor-independent mechanisms. It also suppresses the TLR4 pathway and reduces inflammation.

Melatonin improves vascular cognitive impairment induced by ischemic stroke by remyelination via activation of ERK1/2 signaling and restoration of glutamatergic synapses in the gerbil hippocampus.

Vascular dementia affects cognition by damaging axons and myelin. Melatonin is pharmacologically associated with various neurological disorders. In this study, effects of melatonin on cognitive impairment and related mechanisms were investigated in an animal model of ischemic vascular dementia (IVD). Melatonin was intraperitoneally administered to adult gerbils after transient global cerebral ischemia (tGCI) for 25 days beginning 5 days after tGCI. Cognitive impairment was examined using a passive avoidance test and the Barnes maze test. To investigate mechanisms of restorative effects by melatonin, neuronal damage/death, myelin basic protein (MBP, a marker for myelin), Rip (a marker for oligodendrocyte), extracellular signal-regulated protein kinase1/2 (ERK1/2) and phospho-ERK1/2 (p-ERK1/2), and vesicular glutamate transporter (VGLUT)-1 (a glutamatergic synaptic marker) in the hippocampal Cornu Ammonis 1 area (CA1) were evaluated using immunohistochemistry. Melatonin treatment significantly improved tGCI-induced cognitive impairment. Death of CA1 pyramidal neurons after tGCI was not affected by melatonin treatment. However, melatonin treatment significantly increased MBP immunoreactivity and numbers of Rip-immunoreactive oligodendrocytes in the ischemic CA1. In addition, melatonin treatment significantly increased ERK1/2 and p-ERK1/2 immunoreactivities in oligodendrocytes in the ischemic CA1. Furthermore, melatonin treatment significantly increased VGLUT-1 immunoreactive structures in the ischemic CA1. These results indicate that long-term melatonin treatment after tGCI improves cognitive deficit via restoration of myelin, increase of oligodendrocytes which is closely related to the activation of ERK1/2 signaling, and increase of glutamatergic synapses in the ischemic brain area.

Early IV-injected human dermis-derived mesenchymal stem cells after transient global cerebral ischemia do not pass through damaged blood-brain barrier.

There is lack of researches on effects of intravenously injected mesenchymal stem cells (MSCs) against transient cerebral ischemia (TCI). We investigated the disruption of the neurovascular unit (NVU), which comprises the blood-brain barrier and examined entry of human dermis-derived MSCs (hDMSCs) into the damaged hippocampal CA1 area in a gerbil model of TCI and their subsequent effects on neuroprotection and cognitive function. Impairments of neurons and blood-brain barrier were examined by immunohistochemistry, electron microscopy, and Evans blue and immunoglobulin G leakage. Neuronal death was observed in pyramidal neurons 5-day postischemia. NVU were structurally damaged; in particular, astrocyte end-feet were severely damaged from 2-day post-TCI and immunoglobulin G leaked out of the CA1 area 2 days after 5 min of TCI; however, Evans blue extravasation was not observed. On the basis of the results of NVU damages, ischemic gerbils received PKH2-transfected hDMSCs 3 times at early times (3 hr, 2, and 5 days) after TCI, and fluorescence imaging was used to detect hDMSCs in the tissue. PKH2-transfected hDMSCs were not found in the CA1 from immediate time to 8 days after injection, although they were detected in the liver. Furthermore, hDMSCs transplantation did not protect CA1 pyramidal neurons and did not improve cognitive impairment. Intravenously transplanted hDMSCs did not migrate to the damaged CA1 area induced by TCI. These findings suggest no neuroprotection and cognitive improvement by intravenous hDMSCs transplantation after 5 min of TCI.

Age­dependent decreases in insulin­like growth factor­I and its receptor expressions in the gerbil olfactory bulb.

Insulin­like growth factor­I (IGF­I) is a multifunctional protein present in the central nervous system. A number of previous studies have revealed alterations in IGF­I and its receptor (IGF­IR) expression in various regions of the brain. However, there are few reports on age­dependent alterations in IGF­I and IGF­IR expressions in the olfactory bulb, which contains the secondary neurons of the olfactory system. The present study examined the cellular morphology in the olfactory bulb by using cresyl violet (CV) staining at postnatal month (PM) 3 in the young group, PM 6 in the adult group and PM 24 in the aged group in gerbils. In addition, detailed examinations were performed of the protein levels and immunoreactivities of IGF­I and IGF­IR in the olfactory bulb in each group. There were no significant changes in the cellular morphology between the three groups. The protein levels and immunoreactivities of the IGF­I and IGF­IR were the highest in the young group and they decreased with age. He protein levels and immunoreactivities of the IGF­I and IGF­IR were the lowest in the aged group. In brief, our results indicate that IGF­I and IGF­IR expressions are strong in young olfactory bulbs and significantly reduced in aged olfactory bulbs. In conclusion, subsequent decreases in IGF­I and IGF­IR expression with age may be associated with olfactory decline. Further studies are required to investigate the roles of IFG­I and IGF­IR in disorders of the olfactory system.

Rufinamide, an antiepileptic drug, improves cognition and increases neurogenesis in the aged gerbil hippocampal dentate gyrus via increasing expressions of IGF-1, IGF-1R and p-CREB.

Rufinamide is a novel antiepileptic drug and commonly used in the treatment of Lennox-Gastaut syndrome. In the present study, we investigated effects of rufinamide on cognitive function using passive avoidance test and neurogenesis in the hippocampal dentate gyrus using Ki-67 (a marker for cell proliferation), doublecortin (DCX, a marker for neuroblast) and BrdU/NeuN (markers for newly generated mature neurons) immunohistochemistry in aged gerbils. Aged gerbils (24-month old) were treated with 1 mg/kg and 3 mg/kg rufinamide for 4 weeks. Treatment with 3 mg/kg rufinamide, not 1 mg/kg rufinamide, significantly improved cognitive function and increased neurogenesis, showing that proliferating cells (Ki-67-immunoreactive cells), differentiating neuroblasts (DCX-immunoreactive neuroblasts) and mature neurons (BrdU/NeuN-immunoreactive cells) in the aged dentate gyrus compared with those in the control group. When we examined its mechanisms, rufinamide significantly increased immunoreactivities of insulin-like growth factor-1 (IGF-1), its receptor (IGF-1R), and phosphorylated cAMP response element binding protein (p-CREB). However, rufinamide did not show any increase in immunoreactivities of brain-derived neurotrophic factor and its receptor. Therefore, our results indicate that rufinamide can improve cognitive function and increase neurogenesis in the hippocampus of the aged gerbil via increasing expressions of IGF-1, IGF-1R and p-CREB.

Melatonin attenuates scopolamine-induced cognitive impairment via protecting against demyelination through BDNF-TrkB signaling in the mouse dentate gyrus.

Animal models of scopolamine-induced amnesia are widely used to study underlying mechanisms and treatment of cognitive impairment in neurodegenerative diseases such as Alzheimer's disease (AD). Previous studies have identified that melatonin improves cognitive dysfunction in animal models. In this study, using a mouse model of scopolamine-induced amnesia, we assessed spatial and short-term memory functions for 4 weeks, investigated the expression of myelin-basic protein (MBP) in the dentate gyrus, and examined whether melatonin and scopolamine cotreatment could keep cognitive function and MBP expression. In addition, to study functions of melatonin for keeping cognitive function and MBP expression, we examined expressions of brain-derived neurotrophic factor (BDNF) and tropomycin receptor kinase B (TrkB) in the mouse dentate gyrus. Scopolamine (1 mg/kg) and melatonin (10 mg/kg) were intraperitoneally treated for 2 and 4 weeks. Two and 4 weeks after scopolamine treatment, mice showed significant cognitive impairment; however, melatonin and scopolamine cotreatment recovered cognitive impairment. Two and 4 weeks of scopolamine treatment, the density of MBP immunoreactive myelinated nerve fibers was significantly decreased in the dentate gyrus; however, scopolamine and melatonin cotreatment significantly increased the scopolamine-induced reduction of MBP expression in the dentate gyrus. Furthermore, the cotreatment of scopolamine and melatonin significantly increased the scopolamine-induced decrease of BDNF and TrKB immunoreactivity in the dentate gyrus. Taken together, our results indicate that melatonin treatment exerts anti-amnesic effect and restores the scopolamine-induced reduction of MBP expression through increasing BDNF and TrkB expressions in the mouse dentate gyrus.

Long-term treadmill exercise improves memory impairment through restoration of decreased synaptic adhesion molecule 1/2/3 induced by transient cerebral ischemia in the aged gerbil hippocampus.

Exercise improves cognitive impairments induced by transient cerebral ischemia, and modulates synaptic adhesion molecules. In this study, we investigated effects of long-term treadmill exercise on cognitive impairments and its relation to changes of synaptic cell adhesion molecule (SynCAM) 1/2/3 in the hippocampus after 5 min of transient cerebral ischemia in aged gerbils. Animals were assigned to sedentary and exercised groups, given treadmill exercise for 4 consecutive weeks from 5 days after transient ischemia, and evaluated cognitive function through passive avoidance test and Morris water maze test. SynCAM 2 protein levels were determined in the hippocampus by western blot. In addition, neuronal and synaptic changes were examined by NeuN immunohistochemistry, and SynCAM 1/2/3 and MAP2 double immunofluorescence, respectively. We found that transient cerebral ischemia led to neuronal death in the CA1 area and dentate gyrus, and impaired -memory function; however, 4 weeks of treadmill exercise improved ischemia-induced memory impairment. In addition, SynCAM 1/2/3 and SynCAM 2 expression in the hippocampus was significantly decreased in the sedentary group after transient cerebral ischemia; however, SynCAM 1/2/3 expressionand and SynCAM 2 protein level was significantly increased in the ischemic group with exercise. These results suggest that long-term treadmill exercise improves memory impairment through the restoration of decreased SynCAM 1/2/3 expression in the hippocampus induced by transient cerebral ischemia in the aged gerbil.

Melatonin Improves Cognitive Deficits via Restoration of Cholinergic Dysfunction in a Mouse Model of Scopolamine-Induced Amnesia.

Melatonin is known to improve cognitive deficits, and its functions have been studied in various disease models, including Alzheimer's disease. In this study, we investigated effects of melatonin on cognition and the cholinergic system of the septum and hippocampus in a mouse model of scopolamine-induced amnesia. Scopolamine (1 mg/kg) and melatonin (10 mg/kg) were administered intraperitoneally to mice for 2 and 4 weeks. The Morris water maze and passive avoidance tests revealed that both treatments of scopolamine significantly impaired spatial learning and memory; however, 2- and 4-week melatonin treatments significantly improved spatial learning and memory. In addition, scopolamine treatments significantly decreased protein levels and immunoreactivities of choline acetyltransferase (ChAT), high-affinity choline transporter (CHT), vesicular acetylcholine transporter (VAChT), and muscarinic acetylcholine receptor M1 (M1R) in the septum and hippocampus. However, the treatments with melatonin resulted in increased ChAT-, CHT-, VAChT-, and M1R-immunoreactivities and their protein levels in the septum and hippocampus. Our results demonstrate that melatonin treatment is effective in improving the cognitive deficits via restoration of the cholinergic system in the septum and hippocampus of a mouse model of scopolamine-induced amnesia.

Effects of Scopolamine and Melatonin Cotreatment on Cognition, Neuronal Damage, and Neurogenesis in the Mouse Dentate Gyrus.

It has been demonstrated that melatonin plays important roles in memory improvement and promotes neurogenesis in experimental animals. We examined effects of melatonin on cognitive deficits, neuronal damage, cell proliferation, neuroblast differentiation and neuronal maturation in the mouse dentate gyrus after cotreatment of scopolamine (anticholinergic agent) and melatonin. Scopolamine (1 mg/kg) and melatonin (10 mg/kg) were intraperitoneally injected for 2 and/or 4 weeks to 8-week-old mice. Scopolamine treatment induced significant cognitive deficits 2 and 4 weeks after scopolamine treatment, however, cotreatment of scopolamine and melatonin significantly improved spatial learning and short-term memory impairments. Two and 4 weeks after scopolamine treatment, neurons were not damaged/dead in the dentate gyrus, in addition, no neuronal damage/death was shown after cotreatment of scopolamine and melatonin. Ki67 (a marker for cell proliferation)- and doublecortin (a marker for neuroblast differentiation)-positive cells were significantly decreased in the dentate gyrus 2 and 4 weeks after scopolamine treatment, however, cotreatment of scopolamine and melatonin significantly increased Ki67- and doublecortin-positive cells compared with scopolamine-treated group. However, double immunofluorescence for NeuN/BrdU, which indicates newly-generated mature neurons, did not show double-labeled cells (adult neurogenesis) in the dentate gyrus 2 and 4 weeks after cotreatment of scopolamine and melatonin. Our results suggest that melatonin treatment recovers scopolamine-induced spatial learning and short-term memory impairments and restores or increases scopolamine-induced decrease of cell proliferation and neuroblast differentiation, but does not lead to adult neurogenesis (maturation of neurons) in the mouse dentate gyrus following scopolamine treatment.

Effects of long­term scopolamine treatment on cognitive deficits and calcium binding proteins immunoreactivities in the mouse hippocampus.

GABAergic projections terminate on numerous hippocampal interneurons containing calcium binding proteins (CBPs), including calbindin D­28k (CB), calretinin (CR) and parvalbumin (PV). Memory deficits and expression levels of CB, CR, and PV were examined in the hippocampal subregions following systemic scopolamine (Scop; 1 mg/kg) treatment for 4 weeks in mice. Scop treatment induced significant memory deficits from 1 week after Scop treatment. CB, CR and PV immunoreactivities distributions were in hippocampal subregions [CA1 and CA3 regions, and the dentate gyrus (DG)]. CB immunoreactivity (CB+) was gradually decreased in all subregions until 2 weeks after Scop treatment, and CB+ was decreased to the lowest level in all subregions at 3 and 4 weeks. CR+ in the CA1 region was gradually decreased until 2 weeks and hardly observed at 3 and 4 weeks; in the CA3 region, CR+ was not altered in all subregions at any time. In the DG, CR+ was gradually decreased until 2 weeks and lowest at 3 and 4 weeks. PV+ in the CA1 region was not altered at 1 week, and gradually decreased from 2 weeks. In the CA3 region, PV+ did not change in any subregions at any time. In the DG, PV+ was not altered at 1 week, decreased at 2 weeks, and lowest at 3 and 4 weeks. In brief, Scop significantly decreased CBPs expressions in the hippocampus ≥3 weeks after the treatment although memory deficits had developed at 1 week. Therefore, it is suggested that Scop (1 mg/kg) must be systemically treated for ≥3 weeks to investigate changes in expression levels of CBPs in the hippocampus.

The relation between gallstone disease and cardiovascular disease.

Gallstone disease (GD) is a common digestive disorder that shares many risk factors with cardiovascular disease (CVD). CVD is an important public health issue that encompasses a large percentage of overall mortality. Several recent studies have suggested an association between GD and CVD, while others have not. In this report, we present a meta-analysis of cohort studies to assess the association between GD and CVD. We included eight studies published from 1980 to 2017, including nearly one million participants. The pooled relative risk (RR, 95% confidence interval [CI]) from the random-effects model associates with GD is 1.23 (95% CI: 1.17-1.30) for fatal and nonfatal CVD events. The pooled RR from the random-effects model of CVD events in female patients with GD is 1.24 (95% CI: 1.16-1.32). In male GD patients, the pooled RR from the random-effects model for CVD is 1.18 (95% CI: 1.06-1.31). Our meta-analysis demonstrates a substantially increased risk of fatal and nonfatal CVD events among patients with a medical history of GD. We suggest that interested investigators should further pursue the subject. In addition, both male and female patients with GD have a risk of CVD, and women have a higher risk than men.

Immunoreactivities of calbindin­D28k, calretinin and parvalbumin in the somatosensory cortex of rodents during normal aging.

Calbindin­D28k (CB), calretinin (CR) and parvalbumin (PV), which regulate cytosolic free Ca2+ concentrations in neurons, are chemically expressed in γ­aminobutyric acid (GABA)ergic neurons that regulate the degree of glutamatergic excitation and output of projection neurons. The present study investigated age­associated differences in CB, CR and PV immunoreactivities in the somatosensory cortex in three species (mice, rats and gerbils) of young (1 month), adult (6 months) and aged (24 months) rodents, using immunohistochemistry and western blotting. Abundant CB­immunoreactive neurons were distributed in layers II and III, and age­associated alterations in their number were different according to the species. CR­immunoreactive neurons were not abundant in all layers; however, the number of CR­immunoreactive neurons was the highest in all adult species. Many PV­immunoreactive neurons were identified in all layers, particularly in layers II and III, and they increased in all layers with age in all species. The present study demonstrated that the distribution pattern of CB­, CR­ and PV­containing neurons in the somatosensory cortex were apparently altered in number with normal aging, and that CB and CR exhibited a tendency to decrease in aged rodents, whereas PV tended to increase with age. These results indicate that CB, CR and PV are markedly altered in the somatosensory cortex, and this change may be associated with normal aging. These findings may aid the elucidation of the mechanisms of aging and geriatric disease.

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.

Pretreated quercetin protects gerbil hippocampal CA1 pyramidal neurons from transient cerebral ischemic injury by increasing the expression of antioxidant enzymes.

Quercetin (QE; 3,5,7,3',4'-pentahydroxyflavone), a well-known flavonoid, has been shown to prevent against neurodegenerative disorders and ischemic insults. However, few studies are reported regarding the neuroprotective mechanisms of QE after ischemic insults. Therefore, in this study, we investigated the effects of QE on ischemic injury and the expression of antioxidant enzymes in the hippocampal CA1 region of gerbils subjected to 5 minutes of transient cerebral ischemia. QE was pre-treated once daily for 15 days before ischemia. Pretreatment with QE protected hippocampal CA1 pyramidal neurons from ischemic injury, which was confirmed by neuronal nuclear antigen immunohistochemistry and Fluoro-Jade B histofluorescence staining. In addition, pretreatment with QE significantly increased the expression levels of endogenous antioxidant enzymes Cu/Zn superoxide dismutase, Mn superoxide dismutase, catalase and glutathione peroxidase in the hippocampal CA1 pyramidal neurons of animals with ischemic injury. These findings demonstrate that pretreated QE displayed strong neuroprotective effects against transient cerebral ischemia by increasing the expression of antioxidant enzymes.