Deficits In Rats Research Articles

Three Dimensional-Arterial Spin Labeling Evaluation of Improved Cerebral Perfusion After Limb Remote Ischemic Preconditioning in a Rat Model of Focal Ischemic Stroke.

PurposeTo investigate the application value of 3D arterial spin labeling (3D-ASL) for evaluating distal limb ischemic preconditioning to improve acute ischemic stroke (AIS) perfusion.Materials and MethodsA total of 40 patients with AISs treated in our hospital from January 2020 to December 2020 were recruited, and 15 healthy individuals who were examined in our hospital during the same period were included as the control group; all of these participants were scored on the National Institutes of Health Stroke Scale (NIHSS) and examined by MRI. Sequences included conventional sequences, diffusion-weighted imaging (DWI), magnetic resonance angiography (MRA), and 3D-ASL, and cerebral infarct volume and cerebral blood flow (CBF) in the area of the infarct lesion were measured. After 3 months of treatment, patients with AIS were scored on the modified Rankin Scale (mRS) and divided into good prognosis and poor prognosis groups. In total, 55 adult male Sprague–Dawley rats were divided randomly into three groups: 20 in the middle cerebral artery occlusion (MCAO) group, 20 in the MCAO + limb remote ischemic preconditioning (LRP) group, and 15 in the sham group. In total, 48 h after the procedures, conventional MRI, DWI, and 3D-ASL sequence data were collected, and 2,3,5-trphenyltetrazolium chloride monohydrate (TTC) staining and behavioral scoring were performed. CBF was recorded in the infarct lesion area and the corresponding contralateral area, and the affected/contralateral relative values (rCBF) were calculated to compare the differences in rCBF between different groups. The pathological changes in brain tissues were observed by HE staining, and the expression of vascular endothelial growth factor (VEGF) and platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) in brain tissues was detected by immunofluorescence and real-time quantitative polymerase chain reaction (RT-qPCR). The protein expression of VEGF was detected by western blotting.ResultsHypertension and internal carotid atherosclerosis are high-risk factors for ischemic stroke, and CBF values in the infarct area are significantly lower than those in the corresponding areas on the contralateral side. NIHSS and mRS scores and CBF values have higher specificity and sensitivity for the prognosis of patients with AIS. LRP significantly reduces the infarct area, improves behavioral deficits in rats with cerebral ischemia, reduces neurological injury and histological damage, protects vascular structures, and promotes neovascularization. In addition, 3D-ASL showed a significant increase in brain tissue perfusion in the ischemic area after LRP, and the expression of VEGF and CD31 showed a significant positive correlation with CBF values.ConclusionThree dimensional (3D) ASL can be used to evaluate LRP to improve stroke perfusion, and its protective effect may be closely related to LRP-induced vascular regeneration.

The effect of the NLRP1 inflammasome on methamphetamine-induced cognitive impairment in rats

Methamphetamine (METH) use disorder has been shown to be in high comorbidity with cognitive deficits. METH-induced cognitive deficits are accompanied by neurotoxicity which could result from neuroinflammation. The potential role of NLRP1 inflammasome (NLRP1) and the downstream signalling pathway in METH-induced cognitive impairment was explored in the current study. Cognitive functions and the changes of NLRP1/Caspase-1/GSDMD signalling pathway were firstly determined in rats receiving daily injections of METH. Subsequently, the effects of aspirin-triggered-lipoxin A4 (ATL), a potent anti-inflammatory mediator, and NLRP1 siRNA was investigated were investigated in both METH-treated rats and HT22 cells. METH induces significant cognitive deficits in rats, using the NOR test. METH-induced cognitive impairment was in line with increased activities of NLRP1, cleaved-Caspase-11, IL-1β and TNF-α and the presence of GSDMD-mediated pyroptosis in the hippocampus of rats. NLRP1 inhibition by ATL significantly attenuated METH-induced cognitive impairment, in conjunction with the decreased activities of NLRP1 and cleaved-Caspase-1, IL-1β and TNF-α. ATL and NLRP1 siRNA also prevented the presence of apoptosis in the hippocampus of METH-treated rats and the cell death in METH-treated HT22 cells. These results reveal a novel role of NLRP1 and the downstream signaling pathways in the complex actions of METH-induced cognitive deficits.

Bisphenol-A Mediated Impaired DRP1-GFER Axis and Cognition Restored by PGC-1α Upregulation Through Nicotinamide in the Rat Brain Hippocampus.

The regulatory network of mitochondrial biogenesis and dynamics is vital for mitochondrial functions and cellular homeostasis. Any impairment in the mitochondrial network leads to neurodegenerative disorders. Our earlier studies suggest that environmental toxicant Bisphenol-A (BPA) exposure reduces neurogenesis by abnormal mitochondrial dynamics and mitochondrial biogenesis through impairment of mitochondrial fission factor dynamin-related protein (DRP1) and mitochondrial import protein GFER, which leads to demyelination, neurodegeneration, and cognitive deficits in the rats. In the present study, we found that chronic BPA exposure reduces PGC-1α levels (master regulator of mitochondrial biogenesis), alters mitochondrial localization of DRP1 and GFER, and reduces the number of PGC-1α/NeuN+ and PGC-1α/β-tubulin+ neurons in the rat hippocampus, suggesting reduced PGC-1α-mediated neurogenesis. Nicotinamide significantly increased PGC-1α protein levels, PGC-1α/NeuN+ co-labeled cells in BPA-treated rat hippocampus and PGC-1α/β-tubulin+ co-labeled cells in neuron culture derived from hippocampal neural stem cells. Interestingly, PGC-1α upregulation by nicotinamide also resulted in increased GFER levels and restored mitochondrial localization of GFER (increased GFER/TOMM20 co-labeled cells) in vitro and in vivo following BPA treatment. Nicotinamide also reduced DRP1 levels and prevented DRP1 mitochondrial localization in BPA-treated neuronal cultures and hippocampus, suggesting reduced mitochondrial fission. This resulted in reduced cytochrome c levels in neuronal culture and reduced hippocampal neurodegeneration (reduced caspase-3/NeuN+ co-labeled neurons) following nicotinamide treatment in BPA-treated group. Consequently, activation of PGC-1α by nicotinamide restored BPA-mediated cognitive deficits in rats. Results suggest that the treatment of nicotinamide has therapeutic potential and rescues BPA-mediated neuronal death and cognitive deficits by upregulating the PGC-1α and GFER-DRP1 link, thus balancing mitochondrial homeostasis.

Assessment of Hippocampal Cell Death and Memory Deficits in Rats Following Neonatal Stress

Objective: Neonatal stress (NS) has harmful effects on the hippocampal neurons of rat neonates. It has been reported to enhance neuronal cell death and impair memory behaviors. The researchers conducted this study in order to assess NS’s effects on hippocampal apoptosis and memory deficits in rat neonates’ hippocampus. Methods: Three groups of male Wistar rat neonates exposed to NS; rat neonates reared with 1 hour neonatal isolation (NI) for 8 consecutive days (P2-P9), rat neonates exposed to febrile seizure (FS) at day 10 (P10) and rat neonates reared with both NI plus FS (NI-FS). Control group was reared normally. Novel object recognition test (NORT) carried out to evaluate the effects of NI, FS and NI-FS on memory deficits. At day 22 (P22), Terminal deoxynucleotidyl transferase- mediated dUTP nick end labeling (TUNEL) assay was done. Results: NORT demonstrated that rat neonates exposed to NI-FS had short-term and long-term memory deficits (P<0.01 and P<0.001). Rat neonates experienced NI had long-term memory deficits (P<0.05). TUNEL assay results showed that NI-FS increased the count of hippocampal apoptotic neurons in Cornu Ammonis 1 (CA1), Cornu Ammonis 3 (CA3) and dentate gyrus (DG) subfields (P<0.001, P<0.001 and P<0.001). Also, NI increased the count of hippocampal TUNEL positive cells in CA3 and DG subfields (P<0.05 and P<0.01). In addition, FS increased the count of hippocampal apoptotic neurons in DG subfield (P<0.05). Conclusion: The present results showed that NS exerted apoptotic effect and induced memory deficits in the hippocampus of rat neonate.

Co-exposure of chronic stress and alumina nanoparticles aggravates hippocampal microglia pyroptosis by activating cathepsin B/NLRP3 signaling pathway

Combined exposure of chronic stress and alumina nanoparticles (AlNPs) aggravates hippocampal injury, but the pathogenesis is unevaluated. This study aimed to investigate the effect and mechanism of co-exposure to chronic stress and AlNPs on hippocampal microglia pyroptosis. In this study, chronic restraint stress (CRS) alone caused NLRP3-mediated hippocampal microglia pyroptosis, but AlNPs did not. Moreover, co-exposure to CRS and AlNPs exacerbated hippocampal microglia pyroptosis, resulting in more severe hippocampal damage and behavioral deficits in rats. Protein-protein interaction network predicted that cathepsin B was a potential regulatory protein of NLRP3. CRS up-regulated cathepsin B expression which had a more pronounced increase in co-exposure group. Whereas, caspase-1 inhibitor VX-765 alleviated hippocampal microglia pyroptosis and behavioral deficits in rats. Consistent with in vivo results, co-exposure of corticosterone and AlNPs aggravated NLRP3-mediated pyroptosis and cathepsin B expression in HAPI cells. Nevertheless, the pyroptosis of HAPI cells was inhibited by cathepsin B inhibitor CA-074Me and NLRP3 knockout, respectively. NLRP3 agonist nigericin failed to promote the pyroptosis of HAPI cells in the presence of cathepsin B inhibition. These results demonstrated that co-exposure to chronic stress and AlNPs could aggravate hippocampal microglia pyroptosis by activating cathepsin B/NLRP3 signaling pathway, resulting in hippocampal damage and behavioral deficits.

Neuroprotective Effect of Baicalein Against Oxaliplatin-Induced Peripheral Neuropathy: Impact on Oxidative Stress, Neuro-inflammation and WNT/β-Catenin Signaling.

Oxaliplatin, an effective anti-cancer agent used in the treatment of colorectal cancer, isassociated with severe dose-limiting side effects like peripheral neuropathy, which currently remains a major unmet clinical need. This study was designed to investigate the possible neuroprotective potential of a bioflavonoid, baicalein in an experimental model of oxaliplatin-induced peripheral neuropathy. Rats were administered with a dose of 4mg/kg oxaliplatin i.p. twice per week for four weeks, and were evaluated for behavioral and functional nerve parameters, followed by biochemical, immunohistochemical and western blot analysis. This study shows that baicalein reversed oxaliplatin-induced behavioral deficits and significantly prevented oxaliplatin-induced sensory nerve conduction deficits in rats. Molecular analysis revealed baicalein significantly strengthened the antioxidant defense system by enhancing the expression of MnSOD, HO-1, and GSH levels. Baicalein treatment neutralized the oxaliplatin-induced neuroinflammation, which was evident from the significant loss of inflammatory mediators like TNF-α, IL-6 and a shunted NF-κB nuclear translocation. Additionally, baicalein treatment resulted in a significant downregulation of active β-catenin, Wnt5b and Wnt3a proteins. In line with the in vivo evidences, baicaleintreatment in Neuro2a cells attenuated oxaliplatin-induced ROS, mitochondrial superoxide levels and improved neuritogenesis.Additionally, baicalein did not alter the cell viability of oxaliplatin in HCT-116 cell line. Collectively, these results suggest that baicalein may be useful for management of peripheral neuropathy associated with oxaliplatin.

Sesamin: Insights into its protective effects against lead-induced learning and memory deficits in rats

BackgroundLead (Pb) is one of the most hazardous pollutants that induce a wide spectrum of neurological changes such as learning and memory deficits. Sesamin, a phytonutrient of the lignan class, exhibits anti-inflammatory, anti-apoptotic, and neuroprotective properties. The present study was designed to investigate the effects of sesamin against Pb-induced learning and memory deficits, disruption of hippocampal theta and gamma rhythms, inflammatory response, inhibition of blood δ-aminolevulinic acid dehydratase (δ-ALA-D) activity, Pb accumulation, and neuronal loss in rats. MethodsSesamin treatment (30 mg/kg/day; P.O.) was started simultaneously with Pb acetate exposure (500 ppm in standard drinking water) in rats, and they continued for eight consecutive weeks. ResultsThe results showed that chronic exposure to Pb disrupted the learning and memory functions in both passive-avoidance and water-maze tests, which was accompanied by increase in spectral theta power and theta/gamma ratio, and a decrease in spectral gamma power in the hippocampus. Additionally, Pb exposure resulted in an enhanced tumor necrosis factor-alpha (TNF-α) content, decreased interleukin-10 (IL-10) production, inhibited blood δ-ALA-D activity, increased Pb accumulation, and neuronal loss of rats. In contrast, sesamin treatment improved all the above-mentioned Pb-induced pathological changes. ConclusionThis data suggests that sesamin could improve Pb-induced learning and memory deficits, possibly through amelioration of hippocampal theta and gamma rhythms, modulation of inflammatory status, restoration of the blood δ-ALA-D activity, reduction of Pb accumulation in the blood and the brain tissues, and prevention of neuronal loss.

Human ESC-derived immunity- and matrix- regulatory cells ameliorated white matter damage and vascular cognitive impairment in rats subjected to chronic cerebral hypoperfusion.

ObjectivesThis study investigated the ability of immunity‐ and matrix‐ regulatory cells (IMRCs) to improve cognitive function in a rat model of vascular cognitive impairment.Materials and MethodsA chronic cerebral hypoperfusion (CCH) model was established in rats via permanent bilateral occlusion of the common carotid arteries (two‐vessel occlusion, 2VO). The rats then received intravenous injections of IMRCs or saline. A single injection of different doses of IMRCs (1 × 106 cells/rat, 2 × 106 cells/rat, or 4 × 106 cells/rat) was administered via tail vein 72 h after establishment of the model. To evaluate functional recovery, the rats were subjected to behavioural tests after 30 days of CCH. Imaging, western blotting, immunofluorescence staining, and quantitative real‐time PCR were used to analyse neuroinflammation and white matter injury after 14 and 40 days of CCH. RNA sequencing (RNA‐seq) was used to profile gene expression changes in copine 1 (CPNE1) in response to IMRCs treatment.ResultsIntravenous injection of 4 × 106 IMRCs alleviated white matter damage and ameliorated cognitive deficits in rats subjected to CCH. Immunofluorescence staining suggested that activation of microglia and astrocytes was reduced, and RNA sequencing showed that CPNE1 expression was significantly elevated following treatment with IMRCs.ConclusionsIntravenous injection of IMRCs protected against CCH‐induced white matter injury and cognitive impairment inhibition of microglial activation and regulation of microglia polarization.

Buspirone, a 5-HT1A agonist attenuates social isolation-induced behavior deficits in rats: a comparative study with fluoxetine.

Social isolation is a potent stressor in both humans and animals that results in increased anger-like emotion, (anger in humans), aggression and suicidal ideation in humans [suicidal trait-related behavior in rats (STRB)]. The study's purpose was to compare the effects of buspirone (BUS) and fluoxetine (Flx) on social isolation-induced behavior deficits in rats. The male Wistar rats were randomized into six groups and caged individually for 14 days except for the non stress control (nSC) group. They were then divided into the following groups, stress control (SC), Flx (30), BUS (10), BUS (20) and BUS (40) and treated from day 14 to day 28. On the last day of treatment behavior parameters were recorded. Serum cortisol, blood pressure (BP) measurement, magnetic resonance imaging (MRI) of the rat's brain and brain-derived neurotrophic factor (BDNF) expression were performed. SC group showed a significant increase in anger-like emotion, aggression, irritability score, learned helplessness, increased cortisol level and reduced BDNF. These behavioral deficits were attenuated by BUS and Flx, Both were found to be equally beneficial in preventing anger-like emotions and aggression. Flx, which has been found to promote suicidal thoughts in people, did not reduce irritability in rats, showing that it did not affect it. BUS significantly improved all behavioral traits also reduced cortisol levels, significantly increased BDNF and normalized BP. Neuroimaging studies in SC brains showed a reduction in amygdala size compared to nSC, BUS treatment mitigated this reduction. Buspirone is effective in preventing social isolation induced behavioural-deficits.

Clostridium butyricum RH2 Alleviates Chronic Foot Shock Stress-Induced Behavioral Deficits in Rats via PAI-1.

Recent investigations have demonstrated that the chronic stress-induced behavioral disorders can be ameliorated by probiotics including Clostridium butyricum (C. butyricum) via the gut-brain-axis. However, the molecular mechanisms underlying the beneficial effects of C. butyricum on brain remain largely unknown. Here, we investigated whether chronic foot shock stress (CFSS) paradigm used for a hypertensive animal model could induce mood disorders such as anxiety, depression and cognitive impairments. Then, we assessed the impact of C. butyricum RH2 on the behavior disorders and neurobiological alterations in the hippocampus. Male Sprague-Dawley (SD) rats received intermittent electric shocks for consecutive 14 days and were treated with C. butyricum RH2 for 17 days. Anxiety- or depression-like behaviors were evaluated by open field test (OFT), and elevated plus maze (EPM). The Morris water maze test (MWM) was used to evaluate the cognitive functions. CFSS intervention led to mild anxiety- or depression-like behavior or cognitive impairment and C. butyricum RH2 treatment reversed the CFSS-induced symptoms. The serum ACTH or CORT was increased following CFSS but was completely reversed by C. butyricum RH2 treatment. In the hippocampus of CFSS rats, the expressions of BDNF and TrkB were downregulated but proBDNF and P75NTR were upregulated. These expression changes were partially reversed by C. butyricum RH2, suggesting a mode of action on BDNF and proBDNF balance. CFSS exposure resulted in downregulation of tissue-type plasminogen activator (tPA) but upregulation of plasminogen activator inhibitor 1(PAI-1), which could contribute to the decrease in BDNF by reduced conversion from proBDNF to BDNF in the hippocampus. C. butyricum RH2 treatment reversed the upregulated PAI-1 but not the downregulated tPA, which was in parallel with the amelioration of behavioral abnormalities, suggesting a novel tPA independent mechanism for PAI-1 action. Our results demonstrate for the first time that C. butyricum RH2 attenuates stress-induced behavior disorders via inhibiting the expression of brain PAI-1.

Comprehensive insight into the neurotoxic mechanisms of low dose Pb exposure in Wistar rats: Benchmark dose analysis

Lead (Pb) is a toxic metal that affects almost all human's system and organs, with the nervous system as the most sensitive. Better understanding of the Pb neurobehavioral effects and neurotoxicity requires realistic study scenarios based on low level exposure. The aim of this study was to determine neurotoxic effects and mechanisms of Pb in six low doses and to establish dose-response relationship for these effects and related Benchmark dose (BMD). Forty-two, male albino Wistar rats were randomized into seven groups, control and Pb-exposed: 0.1, 0.5, 1, 3, 7 and 15 mg Pb/kg body weight/day (oral gavage) for 28 days. Behavioural tests (Elevated plus maze test, Spontaneous locomotor activity test and Novel object recognition test) were conducted in the last week of experiment, in the control, lower (0.5 mg Pb/kg), middle (3 mg Pb/kg) and higher (15 mg Pb/kg) dose groups. The acetylcholinesterase activity, oxidative status and essential elements levels (Cu, Zn, Mn and Fe) were measured in brain tissue along with histological analyses. External and internal dose-response analyses were performed using PROASTweb 70.1 software. The results have shown that subacute exposure to very low doses of Pb resulted in memory deficits in rats that was accompanied with acetylcholinesterase enzyme activity decrease. The observed hyperactive behaviour was accompanied by dose-dependent induction of brain oxidative stress and Zn elevation. The histological alterations in Purkinje cells were only detected in the group treated with the highest Pb dose. The lowest BMD considering entire oxidative status was calculated based on total oxidative status (4.5e-06 mg Pb/kg b.w./day). The findings reported in our study may be beneficial in further evaluating the health consequences and human health risk assessment of low-level Pb exposure.

Postnatal GABAA Receptor Activation Alters Synaptic Plasticity and Cognition in Adult Wistar Rats.

Early life alteration in the activity of gamma-aminobutyric acid (GABA) receptors is associated with long-lasting developmental effects on the brain and behavior. GABAA receptors act as excitatory rather than inhibitory in neonates. Excessive activation of GABAA receptors during the early postnatal period may affect cognitive functions later in life. In this study, we sought to determine whether neonatal activation of GABAA receptors with muscimol can alter the electrophysiology profile of hippocampal CA1 neurons and spatial learning and memory in adult rats. Male and female Wistar rat pups received a subcutaneous injection of either saline or muscimol (500µg/kg) on postnatal days (PND) 7, 9, and 11 and then underwent different electrophysiology and behavioral experiments in adulthood. Early life treatment with muscimol did not alter the basic synaptic transmission but significantly reduced the paired-pulse facilitation (PPF) in the CA1 area. Neonatal application of muscimol led to a pronounced decrease in long-term potentiation (LTP) and long-term depression (LTD) in CA1 neurons along with a declined theta-burst responses in both sexes. We obtained some evidence that neonatal GABAA activation leads to reduced brain-derived neurotrophic factor (BDNF) in the hippocampus and prefrontal cortex. Our electrophysiology data was supported with spatial reference and working memory deficits in rats. This study provides the first detailed description of altered electrophysiology in hippocampal CA1 neurons in adult rats undergone GABAA activation early in life.

Caspase Inhibition Restores NEP Expression and Rescues Olfactory Deficit in Rats Caused by Prenatal Hypoxia.

Development of the olfactory system begins early in embryogenesis and is important for the survival of new-borns in postnatal life. Olfactory malfunction in early life disrupts development of behavioural patterns while with ageing manifests development of neurodegenerative disorders. Previously, we have shown that prenatal hypoxia in rats leads to impaired olfaction in the offspring and correlates with reduced expression of a neuropeptidase neprilysin (NEP) in the brain structures involved in processing of the olfactory stimuli. Prenatal hypoxia also resulted in an increased activity of caspases in rat brain and its inhibition restored NEP content in the brain tissue and improved rat memory. In this study, we have analysed effects of intraventricular administration of a caspase inhibitor Ac-DEVD-CHO on NEP mRNA expression, the number of dendritic spines and olfactory function of rats subjected to prenatal hypoxia on E14. The data obtained demonstrated that a single injection of the inhibitor on P20 restored NEP mRNA levels and number of dendritic spines in the entorhinal and parietal cortices, hippocampus and rescued rat olfactory function in food search and odour preference tests. The data obtained suggest that caspase activation caused by prenatal hypoxia contributes to the olfactory dysfunction in developing animals and that caspase inhibition restores the olfactory deficit via upregulating NEP expression and neuronal networking. Because NEP is a major amyloid-degrading enzyme, any decrease in its expression and activity not only impairs brain functions but also predisposes to accumulation of the amyloid-β peptide and development of neurodegeneration characteristic of Alzheimer's disease.

Amelioration of oxidative stress, cholinergic dysfunction, and neuroinflammation in scopolamine-induced amnesic rats fed with pomegranate seed.

This study aimed to investigate the effects of pomegranate (Punica granatum L.) seed hydro-ethanolic extract (PSE) on cholinergic dysfunction, neuroinflammation, and oxidative stress in the scopolamine-induced amnesic rats. The rats were given PSE (200, 400, and 800mg/kg, gavage) for 3weeks. In the third week, scopolamine was administered 30min before the Morris water maze (MWM) and passive avoidance (PA) tests. Oxidative stress indicators, acetylcholinesterase (AChE) activity, and mRNA expression of necrosis factor (TNF)-α, interleukin (IL)-1β, AChE, and M1 acetylcholine receptor (CHRM1) in the brain, were measured. PSE reduced the time (maximum 173%) and distance (maximum 332%) required to reach the platform during MWM learning (P < 0.001). In the prob test (P < 0.001), it increased the target area time (maximum 44%) and distance (maximum 30%). PSE also increased delay and light time (maximums of 86 and 48%, respectively) (P < 0.001), while decreasing the time in dark region of PA (maximums 727%) (P < 0.001). PSE also reduced malondialdehyde and AChE in the cortex (maximum 168 and 171%, respectively) and hippocampus (maximum 151 and 182%, respectively) (P < 0.001). In the PSE-treated groups, the levels of thiol and superoxide dismutase were increased in the cortex (maximum 54 and 65%, respectively) and hippocampus (maximum 90 and 51%, respectively) (P < 0.001). TNF-α, IL-1β, and AChE expressions in the hippocampus were reduced by PSE (maximum 114, 137, and 106%, respectively, P < 0.01). Meanwhile, CHMR expression was increased (66%). PSE successfully alleviated scopolamine-induced memory and learning deficits in rats which is probably via modulating cholinergic system function, oxidative stress, and inflammatory cytokines.

Valproic Acid Inhibits Glial Scar Formation after Ischemic Stroke

Introduction: Cerebral ischemia induces reactive proliferation of astrocytes (astrogliosis) and glial scar formation. As a physical and biochemical barrier, the glial scar not only hinders spontaneous axonal regeneration and neuronal repair but also deteriorates the neuroinflammation in the recovery phase of ischemic stroke. Objectives: Previous studies have shown the neuroprotective effects of the valproic acid (2-n-propylpentanoic acid, VPA) against ischemic stroke, but its effects on the ischemia-induced formation of astrogliosis and glial scar are still unknown. As targeting astrogliosis has become a therapeutic strategy for ischemic stroke, this study was designed to determine whether VPA can inhibit the ischemic stroke-induced glial scar formation and to explore its molecular mechanisms. Methods: Glial scar formation was induced by an ischemia-reperfusion (I/R) model in vivo and an oxygen and glucose deprivation (OGD)-reoxygenation (OGD/Re) model in vitro. Animals were treated with an intraperitoneal injection of VPA (250 mg/kg/day) for 28 days, and the ischemic stroke-related behaviors were assessed. Results: Four weeks of VPA treatment could markedly reduce the brain atrophy volume and improve the behavioral deficits in rats’ I/R injury model. The results showed that VPA administrated upon reperfusion or 1 day post-reperfusion could also decrease the expression of the glial scar makers such as glial fibrillary acidic protein, neurocan, and phosphacan in the peri-infarct region after I/R. Consistent with the in vivo data, VPA treatment showed a protective effect against OGD/Re-induced astrocytic cell death in the in vitro model and also decreased the expression of GFAP, neurocan, and phosphacan. Further studies revealed that VPA significantly upregulated the expression of acetylated histone 3, acetylated histone 4, and heat-shock protein 70.1B in the OGD/Re-induced glial scar formation model. Conclusion: VPA produces neuroprotective effects and inhibits the glial scar formation during the recovery period of ischemic stroke via inhibition of histone deacetylase and induction of Hsp70.1B.

Crocin Protects Malathion-Induced Striatal Biochemical Deficits by Inhibiting Apoptosis and Increasing α-Synuclein in Rats' Striatum.

Long-term exposure to organophosphates might result in neurodegenerative diseases, comprising Parkinson's disease. Malathion is an organophosphate pesticide with high neurotoxicity. Oxidative stress, apoptosis, and α-synuclein accumulation are important underlying mechanisms in Parkinson's disease. According to studies, crocin, an active constituent of saffron, has anti-apoptotic, anti-inflammatory, and antioxidant properties. Thus, the effect of crocin on malathion-induced striatal biochemical deficits in rats was investigated in this study. Six groups of male Wistar rats were used: 1. control (normal saline); 2. malathion (100mg/kg/day, i.p.); 3. crocin (10mg/kg/day, i.p.) + malathion; 4. levodopa (10mg/kg/day, i.p.) + malathion; 5. crocin (40mg/kg/day, i.p.); and 6. polyethylene glycol (PEG) (vehicle of levodopa) groups. The drugs were administered for 28days. The amounts of Bcl-2, Bax, and caspases 3, 8, and 9 proteins in the striatum were measured by western blotting. Also, the amounts of protein and mRNA level of the α-synuclein in striatum tissue were measured by western blotting and RT-qPCR methods. Malathion induced apoptosis by increasing the amount of Bax/Bcl2 ratio and caspases 3 and 9 proteins in rat striatum tissue. It also increased the protein and mRNA level of α-synuclein in striatal tissue. Co-administration of crocin or levodopa with malathion inhibited the toxic effects of malathion on striatal tissue. Crocin ameliorates the neurotoxic effect of malathion by its anti-apoptotic activity and regulating the expression of proteins involved in Parkinson's disease pathogenesis. As a result, crocin has the potential to be used as a treatment for malathion-induced neurotoxicity.

Kisspeptin-13 prevented the electrophysiological alterations induced by amyloid-beta pathology in rat: Possible involvement of stromal interaction molecules and pCREB

Alzheimer's disease (AD) is a progressive neurological disease that slowly causing memory impairments with no effective treatment. We have recently reported that kisspeptin-13 (KP-13) ameliorates Aβ toxicity-induced memory deficit in rats. Here, the possible cellular impact of kisspeptin receptor activation in a rat model of the early stage AD was assessed using whole-cell patch-clamp recording from CA1 pyramidal neurons and molecular approaches. Compared to neurons from the control group, cells from the Aβ-treated group displayed spontaneous and evoked hyperexcitability with lower spike frequency adaptation. These cells had also a lower sag ratio in response to hyperpolarizing prepulse current delivered before a depolarizing current injection. Neurons from the Aβ-treated group exhibited short spike onset latency, lower rheobase and short utilization time compared with those in the control group. Furthermore, phase plot analysis of action potential showed that Aβ treatment affected the action potential features. These electrophysiological changes induced by Aβ were associated with increased expression of stromal interaction molecules (STIMs), particularly (STIM2) and decreased pCREB/CREB ratio. Treatment with KP-13 following Aβ injection into the entorhinal cortex, however, prevented the excitatory effect of Aβ on spontaneous and evoked neuronal activity, increased the latency of onset, enhanced the sag ratio, increased the rheobase and utilization time, and prevented the changes induced Aβ on spike parameters. In addition, the KP-13 application after Aβ treatment reduced the expression of STIMs and increased the pCREB/CREB ratio compared to those receiving Aβ treatment alone. In summary, these results provide evidence that activation of kisspeptin receptor may be effective against pathology of Aβ.

Neuroprotective effects of lentivirus‐mediated aquaporin‐4 gene silencing in rat model of traumatic brain injury

ABSTRACT Background Traumatic brain injury (TBI) is a common clinical condition caused by external force. Aquaporin-4 (AQP4) in astrocytes participates in the generation of cell swelling in TBI. Methods This research explored the effect of AQP4 gene silencing in a TBI rat model. A hydraulic craniocerebral trauma instrument was employed for establishing the TBI rat model. AQP4 expression in the brain was inhibited by the injection of AQP4 shRNA-lentiviral vector. The expression of relative genes was evaluated by Western blot and qRT-PCR. Neuronal apoptosis was analyzed by TUNEL assay. Results AQP4 shRNA treatment inhibited AQP4 expression in the brain of rats with TBI. AQP4 shRNA alleviated TBI-induced brain edema and neurological deficit in rats. Neuronal apoptosis and astrocyte activation in TBI rats were reduced by AQP4 silencing. Conclusion This research demonstrated that AQP4 shRNA-induced silencing of AQP4 in the TBI rat model reduced the expression of AQP4 and GFAP, alleviated brain edema, neurological deficit, neuronal apoptosis and inhibited astrocyte activation.

Neuroprotective Effect of Lentivirus-Mediated FGF21 Gene Delivery in Experimental Alzheimer's Disease is Augmented when Concerted with Rapamycin.

Alzheimer type of dementia is accompanied with progressive loss of cognitive function that directly correlates with accumulation of amyloid beta plaques. It is known that Fibroblast growth factor 21 (FGF21), a metabolic hormone, with strong neuroprotective potential, is induced during oxidative stress in Alzheimer's disease. Interestingly, FGF21 cross-talks with autophagy, a mechanism involved in the clearance of abnormal protein aggregate. Moreover, autophagy activation by Rapamycin delivers neuroprotective role in Alzheimer's disease. However, the synergistic neuroprotective efficacy of overexpressed FGF21 along with Rapamycin is not yet investigated. Therefore, the present study examined whether overexpressed FGF21 along with autophagy activation ameliorated neurodegenerative pathology in Alzheimer's disease. We found that cognitive deficits in rats with intracerebroventricular injection of Amyloid beta1-42 oligomers were restored when injected with FGF21-expressing lentiviral vector combined with Rapamycin. Furthermore, overexpression of FGF21 along with Rapamycin downregulated protein levels of Amyloid beta1-42 and phosphorylated tau and expression of major autophagy proteins along with stabilization of oxidative stress. Moreover, FGF21 overexpressed rats treated with Rapamycin revamped the neuronal density as confirmed by histochemical, cresyl violet and immunofluorescence analysis. These results generate compelling evidence that Alzheimer's disease pathology exacerbated by oligomeric amyloid beta may be restored by FGF21 supplementation combined with Rapamycin and thus present an appropriate treatment paradigm for people affected with Alzheimer's disease.

Abstract TP231: Irisin, Elicited By Low Frequency Whole Body Vibration Or Exogenously, Improves Post-Stroke Cognition And Reduces Infarct Volume In Middle-Aged Rats

Significance: Low frequency whole body vibration (LFV) at 40 Hz, a low impact form of exercise, for a month following mild transient middle-cerebral artery occlusion (tMCAO) reduces infarct volume and improves motor function in reproductively senescent, middle-aged female rats (1). In humans, LFV was shown to increase circulating levels of irisin, a skeletal muscle-derived hormone. Irisin has also been shown to play a crucial role in preserving mitochondrial function, preventing oxidative stress, and elevating expression of BDNF, among other neuroprotective measures. The current study aims to investigate the efficacy of LFV in ameliorating post-tMCAO cognitive deficits and to determine the putative role of irisin in conferring the benefits of LFV in middle-aged rats. Methods: Middle-aged rats of both sexes (5-8) were randomly assigned to tMCAO (90 min), or sham surgery followed by exposure to either LFV (twice a day for 15 min each for 5 days a week over a month) or no LFV treatment groups. Following the last LFV treatment, rats were tested for hippocampus-dependent learning and memory using a water maze followed harvesting brain and blood samples for histopathological and inflammatory marker analyses, respectively. In a parallel experiment in the absence of LFV, middle-aged female rats were randomly assigned to either saline or irisin treatment following tMCAO. Recombinant irisin was purchased from PeproTech (Rocky Hill, NJ). Rats were treated with irisin (0.2 μg/g BW; IP) or saline for a month followed by their brains were assessed by histopathology. Results: Post-tMCAO LFV significantly lessens cognitive deficits in rats of both sexes. It also significantly decreased circulating pro-inflammatory cytokines and increased serum levels of native irisin. Quantification of infarct volume irisin-treated rats demonstrated that, compared to saline, infarct volume was significantly reduced. Saline treatment resulted in 234 ± 30 mm 3 , while irisin treatment yielded 128 ± 34 mm 3 (p&lt;0.05) of infarct volume. Conclusion: Irisin, either as elicited by LFV or administered exogenously without LFV, regulates brain metabolism and inflammation and its beneficial effects can be stimulated by LFV.Reference: 1. Raval, A.P., et al., Int J Mol Sci, 2018. 19 (9).