Passive Avoidance Test Research Articles

Protective effects of alpha-lipoic acid on anxiety-like behavior, memory and prevention of hippocampal oxidative stress in methamphetamine-treated rats.

Alpha-lipoic acid is an essential cofactor for aerobic metabolism and acts as a potent antioxidant in the body. It has been shown that acute exposure to methamphetamine induces oxidative stress, which is responsible for severe cognitive deficits in animals. The hippocampus plays a crucial role in the processing of memory and anxiety-like behavior. In this study, preventive effect of the alpha-lipoic acid on memory impairment in methamphetamine-induced neurotoxicity was investigated. Wistar male rats (200-220g) were allocated to five groups (seven rats in each group): (1) saline + saline, (2) saline + vehicle (sunflower oil as alpha-lipoic acid solvent), (3) methamphetamine + vehicle, (4) methamphetamine + alpha-lipoic acid 10mg/kg, and (5) methamphetamine + alpha-lipoic acid 40mg/kg. Rats received intraperitoneal methamphetamine repeatedly (2 × 20mg/kg, 2h interval). Alpha-lipoic acid was injected 30min, 24h, and 48h after the last injection of methamphetamine. The passive avoidance test and open field were used for evaluation of memory retrieval and anxiety, respectively. After behavioral test, rats were anesthetized, their brains were extracted, and after preparing hippocampal homogenates, malondialdehyde (MDA) level, catalase, and superoxide dismutase (SOD) activities were evaluated. Statistical analysis showed that injection of saline or sunflower oil had no significant effect on anxiety, memory, or oxidative stress markers. Methamphetamine induced memory impairment, increased anxiety-like behavior and MDA level, but it reduced catalase and SOD activity. Treatment with alpha-lipoic acid decreased MDA, increased catalase and SOD activity, and also prevented memory impairment and anxiety-like behavior. Our results showed that alpha-lipoic acid protected the hippocampus from oxidative stress by elevating SOD and CAT activities and reduced memory impairment following acute methamphetamine injection. These findings suggest that alpha-lipoic acid may have a protective effect against the adverse effects of methamphetamine exposure on the hippocampus. Therefore, the current data indicated that ALA can reduce oxidative stress predominantly by its antioxidant property.

The elderberry diet protection against intrahippocampal Aβ-induced memory dysfunction; the abrogated apoptosis and neuroinflammation.

This study evaluates whether elderberry (EB) effectively decreases the inflammation and oxidative stress in the brain cells to reduce Aβ toxicity. In the Aβ+EB group, EB powder was added to rats' routine diet for eight consecutive weeks. Then, spatial memory, working memory, and long-term memory, were measured using the Morris water maze, T-maze, and passive avoidance test. Also, in this investigation immunohistopathology, distribution of hippocampal cells, and gene expression was carried out. Voronoi tessellation method was used to estimate the spatial distribution of the cells in the hippocampus. In addition to improving the memory functions of rats with Aβ toxicity, a reduction in astrogliosis and astrocytes process length and the number of branches and intersections distal to the soma was observed in their hippocampus compared to the control group. Further analysis indicated that the EB diet decreased the caspase-3 expression in the hippocampus of rats with Aβ toxicity. Also, EB protected hippocampal pyramidal neurons against Aβ toxicity and improved the spatial distribution of the hippocampal neurons. Moreover, EB decreased the expression of inflammatory and apoptotic genes. Overall, our study suggest that EB can be considered a potent modifier of astrocytes' reactivation and inflammatory responses.

Fluoroethylnormemantine (FENM) shows synergistic protection in combination with a sigma-1 receptor agonist in a mouse model of Alzheimer's disease

Fluoroethylnormemantine (FENM) is a Memantine derivative with anti-amnesic and neuroprotective activities showed in the Aβ25-35 pharmacological mouse model of Alzheimer's disease (AD). As AD is a complex multi-factorial neurodegenerative pathology, combination therapies relying on drugs acting through different pathways, have been suggested to more adequately address neuroprotection. As several agonists of the sigma-1 receptor (S1R), an intracellular chaperone, are presently in phase 2 or 3 clinical trials in neurodegenetrative diseases including AD, we examined the potentialities of S1R drug-based combinations with FENM, or Memantine. Aβ25-35-treated mice were treated with S1R agonists (PRE-084, Igmesine, Cutamesine) and/or FENM, or Memantine, during 7 days after intracerebroventricular administration of oligomerized Aβ25-35. Mice were then tested for spatial short-term memory on day 8 and non-spatial long-term memory on days 9–10, using the spontaneous alternation or passive avoidance tests, respectively. The FENM or Memantine combination with Donepezil, that non-selectively inhibits acetylcholinesterase and activates S1R, was also tested. The efficacy of combinations using maximal non-active or minimal active doses of S1R agonist or FENM was analyzed using calculations of the combination index, based on simple isobologram representation. Data showed that most of the FENM-based combinations led to synergistic protection against Aβ25-35-induced learning deficits, for both long- and short-term memory responses, with a higher efficiency on the latter. Memantine led to synergistic combination in short-term memory but poorly in long-term memory responses, with either PRE-084 or Donepezil. These study showed that drug combinations based on FENM and S1R agonists may lead to highly effective and synergistic protection in AD, particularly on short-term memory.

Preparation and characterization of brain-targeted polymeric nanocarriers (Frankincense-PMBN-lactoferrin) and in-vivo evaluation on an Alzheimer's disease-like rat model induced by scopolamine

Experiments have demonstrated that frankincense may offer protection against scopolamine-induced Alzheimer's disease by mitigating cholinergic dysfunction and inhibiting inflammatory mediators. Nevertheless, its instability and limited water solubility lead to diminished medicinal efficacy. In this study, we utilized PMBN (poly [MPC-co-(BMA)–co-(MEONP)]) as a nanocarrier for targeted brain drug delivery of frankincense, employing lactoferrin as a ligand for precise targeting. Characterization of nanoparticle properties was conducted through FTIR and FESEM analysis, and the in-vitro drug release percentage from the nanoparticles was quantified. To induce Alzheimer's-like dementia in rats, scopolamine was intraperitoneally administered at a dose of 1 mg/kg/day for 14 days. Subsequently, behavioral assessments (Y-maze, passive avoidance test, tail suspension test) were performed, followed by evaluations of acetylcholinesterase (AChE), reduced glutathione (GSH), catalase (CAT), and brain histopathology at the conclusion of the treatment period.The results revealed that the nanoparticles had a size of 106.6 nm and a zeta potential of −3.8 mV. The maximum release of frankincense in the PBS environment from PMBN nanoparticles was 18.2 %, in accordance with the Peppas model. Behavioral tests indicated that targeted drug nanoparticles (F-PMBN-Lf) exhibited the capability to alleviate stress and depression while enhancing short-term memory in scopolamine-induced animals. Additionally, F-PMBN-Lf counteracted the scopolamine-induced elevation of AChE activity and GSH levels. However, it resulted in decreased activity of the antioxidant enzyme CAT compared to the scopolamine group. Histological analysis of brain tissue suggested that F-PMBN-Lf exerted a notable neuroprotective effect, preserving neuronal cells in contrast to the scopolamine-induced group. It appears that the polymer nanoparticles containing this plant extract have introduced a novel neuroprotective approach for the treatment of Alzheimer's disease.

Neuroprotective effects of vitamin D in an Alzheimer's disease rat model: Improvement of mitochondrial dysfunction via calcium/calmodulin-dependent protein kinase kinase 2 activation of Sirtuin1 phosphorylation.

Mitochondrial dysfunction is an early event in Alzheimer's disease (AD) pathogenesis. To assess the impact of vitamin D3 (Vit.D) on neurogenesis, we investigated its role in mitigating cognitive impairment and mitochondrial dysfunction through calcium/calmodulin-dependent protein kinase kinase 2 (CAMKK2)-mediated phosphorylation of Sirtuin1 (SIRT1) in an aluminum-chloride-D-galactose (AlCl3-D-gal)-induced AD rat model. Rats were distributed into four groups: control, AlCl3 + D-gal (10 + 60 mg/kg, ip), Vit.D (500 IU/kg, po), and AlCl3 + D-gal+Vit.D. Novel object recognition (NOR), Morris Water Maze, and passive avoidance (PA) tests were used to measure memory abilities. The hippocampal tissue was used to assess vitamin D3 receptor (VDR) and peroxisome-proliferator-activated-receptor-γ-coactivator-1α (PGC-1α) expression by quantitative real-time polymerase chain reaction (qRT-PCR), CAMKK2, p-SIRT1, phosphorylated-AMP-activated protein kinase (p-AMPK), dynamin-related-protein-1 (Drp1), and mitofusin-1 (Mnf1) proteins by western blot and Ca2+ levels, endothelial nitic oxide synthase (eNOS), superoxide dismutase (SOD), amyloid beta (Aβ), and phospho tau (p-Tau) via enzyme-linked immunosorbent assay(ELISA) in addition to histological and ultrastructural examination of rat's brain tissue. Vit.D-attenuated hippocampal injury reversed the cognitive decline and Aβ aggregation, and elevated p-Tau levels in the AlCl3 + D-gal-induced AD rat model. In AlCl3 + D-gal-exposed rats, Vit.D induced VDR expression, normalized Ca2+ levels, elevated CAMKK2, p-AMPK, p-SIRT1, and PGC-1α expression. Vit.D reduced Drp1, induced Mnf1, increased mitochondrial membrane potential, preserved mitochondrial structure, restored normal mitochondrial function, and retained normal eNOS level and SOD activity in AlCl3 + D-gal rats. In conclusion, our findings proved that Vit.D may ameliorate cognitive deficits in AlCl3 + D-gal-induced AD by restoring normal mitochondrial function and reducing inflammatory and oxidative stress via CAMKK2-AMPK/SIRT1 pathway upregulation.

Cadaba indica Leaf Extract: Neuroprotection and Cognitive Enhancement with Safety Profile Comparison

Aim: The current study aims to investigate the toxicity profile, the anti-amyloidogenic, and anti-ameliorative effects of crude ethanol extract from Cadaba indica leaves in contrast with a prominent drug. Methods: Phytochemical screening of the ethanol extract of C. indica was performed by GC–MS analysis. The cell viability of SH-SY5Y cells was assessed by a neutral red uptake assay, and neuroprotective effects were evaluated against the Aβ25–35 toxicity in SH-SY5Y cells experienced pretreatment with plant extracts. In acute and sub-chronic toxicity studies were conducted according to the OECD guidelines to ascertain the toxicity profile in Swiss Albino mice. The ameliorative effect of the extract was measured by behavioral test on drug-induced learning and memory impairment in mice. Results: Fifteen phytochemical compounds were revealed in GC–MS. Inhibitory concentration (IC50) was found to be >100 μg/mL on SH-SY5Ycells. Protection of SH-SY5Y cells from Aβ25-35-induced toxicity at the concentration of 25 μg/mL was observed. No clinical toxicity signs were observed in the plant treated group when compared to the control group in both acute and sub-chronic toxicity studies at the maximum of 2000 mg/kg dose. The oral lethal median dose (LD50) was estimated to be >2000 mg/kg. There was a reduction of the scopolamine-induced amnesia observed in the passive avoidance test at 100 mg/kg. Conclusion: The results conclude that C. indica extracts might contain potent secondary metabolites that might primarily enhance the neuroprotective effects and improve in cognitive impairments induced by cholinergic dysfunction.

The Effect on Differentiation and Maturation of Oligodendrocyte by Age of Cerebral Palsy Modeling Using Sprague Dawley Rat

Cerebral palsy induces motor, cognitive, attention, and behavioral dysfunctions caused by brain damages. It is caused by damage to oligodendrocyte induced hypoxic ischemia and injection in the perinatal period. Therefore, an animal models that performed hypoxiaischemia-lipopolysaccharide injection (HIL) at 4-7 days of age (PND) are widely used. However, there is a difference in the brain damage due to exposure time under the hypoxic condition, gender, and ligation surgery techniques. In this paper, the optimal surgical age was found by analyzing behavioral tests, inflammatory reactions, and the differentiation and maturation of oligodendrocytes by performing HIL on rats 4, 5, 6, and 7 days old, respectively. On the 4th, 5th, 6th, and 7th days of birth (PND) of male Sprague Dawley rats, the right common carotid artery was ligated, they were incubated in an environment of 37℃, 92% N2, and 8% O2, and then peritoneally injected LPS (1 mg/kg) after removing the ligation. The rota-rod test were performed at PND 10, 20, 30, and 40, and memory tests such as passive avoidance and Morris water maze tests were performed on PND36-40, and then they were euthanized to analyze inflammatory indicators (NF-kB, TNF-a, IL-6, iNOS, and COX2) and indicators of the differentiation and maturation (Olig2, CNPase). In the case of the PND4 group, the limb coordination test were significantly different from that of the normal group, but there was no difference in other analyses. In the case of PND5 group, there were significantly differences in limb coordination tests, memory tests, inflammatory indicators, and differentiation and maturation of oligodendrocyte. In the case of the PND6 group, there was a significantly difference in limb coordination and memory tests, and a significantly increase in inflammatory indicators compared to other groups, but the mortality rate increased and indicators of the differentiation and maturation of oligodendrocyte were increased. In the case of the PND7 group, the limb coordination test showed significantly differences compared to normal group, but there was no difference from the normal group in other analyses. In conclusion, this study suggests that the PND5 group, where abnormal behavioral tests, an increase in appropriate inflammatory indicators, and a decrease in maturation and differentiation-related proteins of oligodendrocyte are comprehensively observed, is most suitable.

Arc/Arg3.1 expression in the brain tissues during the learning process in Alzheimer's disease animal models

Introduction. Arc/Arg3.1 is a common marker of neuronal activation for learning and memorizing. Some experimental data show the Arc/Arg3.1 expression in the post-mitotic neurons of the neurogenic niches. At the same time, we still have to understand the importance of such an expression for neurogenesis induced by the learning or memorizing processes, in health and in disease.
 Objective: to evaluate the changes in Arc/Arg3.1 expression in the post-mitotic neurons and to assess the proliferative activity of the neurogenic niche cells in Alzheimer's disease animal models.
 Materials and methods. We divided the C57Bl/6В mice into 2 groups: experimental (n = 15) and control (n = 15). The experimental group were injected with the amyloid- oligomers 2535 in their CA1 hippocampal region while the control mice received normal saline injections in the same region. Passive Avoidance Test (PAT) was used to assess the cognitive functions from the day 9 after the intervention. One hour after each test session we collected the samples of brain tissues to immunohistochemically assess them for the Arc/Arg3.1 expression and PCNA cell proliferation marker.
 Results. At day 11 the count of Arc/Arg3.1+NeuN+ cells in the subgranular zone had significantly increased. In animal neurodegeneration models the 1st and 2nd PAT sessions were associated with a significant increase in Arc/Arg3.1+NeuN+ cells, although by the day 11 their count significantly decreased. The count of Arc/Arg3.1+ cells in the subventricular and subgranular zones had increased after the 3rd PAT session in the control group while in Alzheimer's disease animal models this was observed only after the 2nd PAT session. Preserved Arc/Arg3.1 expression in the subventricular zone is associated with the increased PCNA cell prolifera- tion marker expression. At the same time, the toxic effect of the amyloid- oligomers suppressed the cells' proliferative activity in the subgranular zone at day 9.
 Conclusions. Despite the toxic effect of the amyloid- oligomers 2535, the post-mitotic neurons of the neurogenic niches retained the ability to express Arc/Arg3.1 in vivo. The obtained results show a transient increase in sensitivity of the post-mitotic neurons of the neurogenic niches for the learning stimuli in the early stages of the Alzheimer-type neurodegeneration.

Comprehensive analysis of N6-methyladenosine-related RNA methylation in the mouse hippocampus after acquired hearing loss

BackgroundThe mechanism underlying cognitive impairment after hearing loss (HL) remains unclear. N6-methyladenosine (m6A) is involved in many neurodegenerative diseases; however, its role in cognitive impairment after HL has not yet been investigated. Therefore, we aimed to analyze the m6A modification profile of the mouse hippocampus after HL exposure. A mouse model of neomycin-induced HL was established. An auditory brainstem-response test was utilized for detecting hearing threshold. The passive avoidance test was served as the mean for evaluating cognitive function. The m6A-regulated enzyme expression levels were analyzed by using reverse transcription quantitative real-time polymerase chain reaction and western blot analyses. RNA sequencing (RNA-Seq) and methylated RNA immunoprecipitation sequencing (MeRIP-Seq) were performed with the aim of investigating gene expression differences and m6A modification in the mouse hippocampus.ResultsNeomycin administration induced severe HL in mice. At four months of age, the mice in the HL group showed poorer cognitive performance than the mice in the control group. METTL14, WTAP, and YTHDF2 mRNA levels were downregulated in the hippocampi of HL mice, whereas ALKBH5 and FTO mRNA levels were significantly upregulated. At the protein level, METTL3 and FTO were significantly upregulated. Methylated RNA immunoprecipitation sequencing analysis revealed 387 and 361 m6A hypermethylation and hypomethylation peaks, respectively. Moreover, combined analysis of mRNA expression levels and m6A peaks revealed eight mRNAs with significantly changed expression levels and methylation.ConclusionsOur findings revealed the m6A transcriptome-wide profile in the hippocampus of HL mice, which may provide a basis for understanding the association between HL and cognitive impairment from the perspective of epigenetic modifications.

Neuroprotective Effect of Chlorogenic Acid against Pentylenetetrazol Induced Kindled Epilepsy in Mice

Background: Epilepsy is a group of chronic neurological disorders characterized by seizures. Kindling, a chronic epileptic mouse model that was used to explore the epileptogenic mechanism and seeking new anti-epileptics. In kindling, sub-convulsive (chemical/ electrical) stimuli are delivered repeatedly and erratically, eventually causes massive convulsions. The aim of this study was to investigate the neuroprotective effects of chlorogenic acid, a phenolic acid derived from coffee, on seizure severity and kindling progression. Memory impairment inflammation due to oxidative stress by pentylenetetrazol (PTZ). Objective: This study was used to investigate the neuroprotective effect of chlorogenic acid against pentylenetetrazol induced kindled epilepsy in mice. Methods: Kindling was provoked by subsequent (one-day-gap) injections of PTZ (subconvulsive; 35 mg/kg; s.c.) for 29 days in mice. The experimental protocol included six groups (n=6) receiving proconvulsant doses of PTZ (35 mg/kg i.p.) every other day for 31 days. Alternating subcutaneous injections of PTZ induced priming with 15 injections of PTZ. Compared with the PTZ group, pre-treatment with chlorogenic acid (5 and 10 mg/kg) 1 h before PTZ administration reduced seizure score, reduced metastasis latency due to increased normal maze, and decreased metastasis latency extension at FST. PTZ-induced biochemical changes were enhanced in chlorogenic acid-treated animals, as indicated by decreased lipid peroxidation (MDA), nitric oxide and AChE levels, and increased SOD, GSH, catalase level. Following PTZ injection, convulsive behaviours were noted for 30 minutes. Open-field-test (locomotor activity), force swimming test (depressive behaviors), elevated plus-maze and passive avoidance tests were employed to evaluate cognition. Brain homogenate was used to estimate oxidative stress (glutathione,superoxide-dismutase, lipid-peroxidation), and acetylcholinesterase activity. Results: This result suggest the neuroprotective potential of chlorogenic acid. This may be correlated with its ability to inhibit oxidative damage and reduce the occurrence of seizures and other related damage. It may be a promising candidate for mitigating the consequences of events. Conclusion: Our findings suggest effect of chlorogenic acid against pentylenetetrazol-induced kindled epilepsy in mice which were established by behavioral and biochemical paradigms

Rubus fruticosus leaf extract inhibits vascular dementia-induced memory impairment and neuronal loss by attenuating neuroinflammation.

Vascular dementia (VaD) is characterized by progressive memory impairment, which is associated with microglia-mediated neuroinflammation. Polyphenol-rich natural plants, which possess anti-inflammatory activities, have attracted scientific interest worldwide. This study investigated whether Rubus fruticosus leaf extract (RFLE) can attenuate VaD. Sprague-Dawley rats were separated into five groups: SO, sham-operated and treated with vehicle; OP, operated and treated with vehicle; RFLE-L, operated and treated with low dose (30 mg/kg) of RFLE; RFLE-M, operated and treated with medium dose (60 mg/kg) of RFLE; and RFLE-H, operated and treated with high dose (90 mg/kg) of RFLE. Bilateral common carotid artery and hypotension were used as a modeling procedure, and the RFLE were intraorally administered for 5 days (preoperative 2 and postoperative 3 days). The rats then underwent memory tests including the novel object recognition, Y-maze, Barnes maze, and passive avoidance tests, and neuronal viability and neuroinflammation were quantified in their hippocampi. The results showed that the OP group exhibited VaD-associated memory deficits, neuronal death, and microglial activation in hippocampi, while the RFLE-treated groups showed significant attenuation in all above parameters. Next, using BV-2 microglial cells challenged with lipopolysaccharide (LPS), we evaluated the effects of RFLE in dynamics of proinflammatory mediators and the upstream signaling pathway. RFLE pretreatment significantly inhibited the LPS-induced release of nitric oxide, TNF-α, and IL-6 and upregulation of the MAPKs/NF-κB/iNOS pathway. Collectively, we suggest that RFLE can attenuate the histologic alterations and memory deficits accompanied by VaD, and these roles are, partly due to the attenuation of microglial activation.

Neurobehavioral effects of the exposure to mercury vapor and methylmercury during postnatal period on mice.

In this study, we investigated the neurobehavioral alterations and modifications of gene expression in the brains of female mice exposed to low-level mercury vapor and/or methylmercury during postnatal development. The mice were exposed to low-level mercury vapor at a mean concentration of 0.094mg/m3 and supplied with tap water containing 5 ppm methylmercury from postnatal day 11 to 12 weeks of age. Behavioral analyses were performed at 17 weeks of age. Total locomotor activity in the open field test and the retention trial performance in the passive avoidance test were significantly reduced in the combined exposure group compared with those in the control group. The differences in locomotor activity and performance in the retention trial at 17 weeks were no longer detected at 45 weeks. These results suggest that the effect of aging on the behavioral abnormalities resulting from postnatal exposure to mercury complexes are not significant. In the microarray analysis of brains in the combined exposure group, the gene expression levels of Ano2 and Sgk1 were decreased. Real-time RT-PCR analysis confirmed these changes caused by combined mercury exposure, showing significant downregulation of Ano2 and Sgk1 in the cerebrum. These genes play key roles in the brain as a calcium-activated chloride channel and as a kinase that responds to cellular stress, respectively. Our findings provide insight into the neurobehavioral changes caused by combined mercury exposure.

Omega-3 fatty acids prevent nicotine withdrawal-induced impairment of learning and memory via affecting oxidative status, inflammatory response, cholinergic activity, BDNF and amyloid-B in rat hippocampal tissues

In the present study, the main objective was to reveal whether treatment by Omega-3 fatty acids could prevent the adverse effects of adolescent nicotine withdrawal on spatial and avoidance memory in male rats. For this purpose, Morris water maze and passive avoidance tests were performed on male Wistar rats and the hippocampal levels of oxidative stress markers, inflammatory indices, brain-derived neurotrophic factor, nitrite, amyloid-B and acetylcholinesterase (AChE) were measured. Moreover, density of dark neurons were assessed in CA1 and CA3 regions. Results showed that adolescent nicotine exposure followed by a period of drug cessation exacerbates the behavioral indices of learning and memory through affecting a variety of biochemical markers within the hippocampal tissues. These changes lead to elevation of oxidative and inflammatory markers, reduction of neurotrophic capacity and increased AChE activity in hippocampal tissues. In addition, it was observed that co-administration of nicotine with Omega-3 fatty acids significantly prevents nicotine withdrawal-induced adverse effects through restoration of the mentioned biochemical disturbances. Therefore, we suggest administration of Omega-3 fatty acids as a safe, inexpensive and effective therapeutic strategy for prevention of memory dysfunctions associated with nicotine abstinence during adolescence.

ACETYLCHOLINESTERASE INHIBITION, NOOTROPIC AND ANTIOXIDANT EFFECT OF EXTRACTS FROM AGAVE SPECIES

Background: The systemic administration of Lipopolysaccharide (LPS) is a pharmacological model to evaluate different processes associated with neurodegeneration; it is capable of causing an increase in the oxidative state in the brain and increasing the activity of the enzyme acetylcholinesterase (ACh-E), involved in the degradation of acetylcholine (ACh). This cholinergic transmission system participates in memory processes, a crucial symptom in neurodegenerative disorders, and its modulation with scopolamine turns out to be an essential tool in the evaluation of plants. Species of the genus Agave are considered a natural resource of economic and cultural importance in Mexico. They possess compounds with anti-inflammatory, antioxidant, and anti-neuroinflammatory activities. Methods: Extracts of A. tequilana (At-A), A. angustifolia (Aan-A), A. americana (Aam-A) at 125 mg/kg were administered to male ICR mice with LPS to evaluate the ACh-E inhibition, the concentration of the antioxidant enzyme Gluthatione Reductase (GR) and the prooxidant enzyme NADPH Oxidase (NOX). Also, the nootropic effect of these extracts on scopolamine-induced cognitive impairment was evaluated. Results: The three Agave species studied decreased the ACh-E enzyme activity, Vmax value, and KM. These products increased the GR concentration from 0.173±0.003 (vehicle) to 0.642±0.002 µMol/mg in At-A, which was the highest one. Regarding NOX, only the A. tequilana extract decreased it (0.513±0.002µMol/mg)compared with Vehicle (0.621±0.008µMol/mg). A. tequilana and A. americana species significantly improved the retention latency parameter (260 seconds) during the passive avoidance test. Conclusion: Agave species showed promising results in developing novel drugs for neurodegenerative disease therapy. Peer Review History: Received: 17 June 2023; Revised: 22 July; Accepted: 27 August, Available online: 15 September 2023 Academic Editor: Dr. Asia Selman Abdullah, Pharmacy institute, University of Basrah, Iraq, asia_abdullah65@yahoo.com Received file: Reviewer's Comments: Average Peer review marks at initial stage: 5.5/10 Average Peer review marks at publication stage: 7.0/10 Reviewers: Dr. Sangeetha Arullappan, Universiti Tunku Abdul Rahman, Malaysia, sangeetha@utar.edu.my Prof. Ali Gamal Ahmed Al-kaf, Sana'a university, Yemen, alialkaf21@gmail.com

Anti-Amnesia-like Effect of Pinus densiflora Extract by Improving Apoptosis and Neuroinflammation on Trimethyltin-Induced ICR Mice.

This study was conducted to investigate the anti-amnestic property of Korean red pine bark extract (KRPBE) on TMT-induced cognitive decline in ICR mice. As a result of looking at behavioral function, the consumption of KRPBE improved the spatial work ability, short-term learning, and memory ability by Y-maze, passive avoidance, and Morris water maze tests. KRPBE suppressed antioxidant system damage by assessing the SOD activity, reduced GSH content, and MDA levels in brain tissue. In addition, it had a protective effect on cholinergic and synaptic systems by regulating ACh levels, AChE activity, and protein expression levels of ChAT, AChE, SYP, and PSD-95. Also, the KRPBE ameliorated TMT-induced mitochondrial damage by regulating the ROS content, MMP, and ATP levels. Treatment with KRPBE suppressed Aβ accumulation and phosphorylation of tau and reduced the expression level of BAX/BCl-2 ratio and caspase 3, improving oxidative stress-induced apoptosis. Moreover, treatment with KRPBE improved cognitive dysfunction by regulating the neuro-inflammatory protein expression levels of p-JNK, p-Akt, p-IκB-α, COX-2, and IL-1β. Based on these results, the extract of Korean red pine bark, which is discarded as a byproduct of forestry, might be used as an eco-friendly material for functional foods or pharmaceuticals by having an anti-amnesia effect on cognitive impairment.

The beneficial effect of 3,6'-Disinapoyl sucrose on the cognitive decline via CREB/BDNF signal pathway in APP/PS1 transgenic mice.

Alzheimer's disease (AD) is a neurodegenerative disorder with insidious onset and progressive development. There is an urgent need to find drugs that prevent, slow the progression of AD. We focus our attention on 3,6'-disinapoyl sucrose (DISS), an oligosaccharide with antidepressant and antioxidant activities. In this work, APP/PS1 transgenic mice were utilized to explore the neuroprotective impact of DISS to provide new applications for prevention and therapy of AD. To assess DISS's neuroprotective impact on learning and memory deficits in APP/PS1 transgenic mice using behavioral tests (Morris water maze, Novel object recognition test, and Passive avoidance test). Morphological alterations of hippocampus neurons were observed by Nissl staining and neuronal of apoptosis were assessed by TUNEL assay. By using ELISA, the expressions of inflammatory factors were evaluated, and Western blotting was used to measure the protein expressions of neuron-related regulators in the hippocampus. DISS significantly ameliorated the cognitive disorder in APP/PS1 transgenic mice, reduced apoptosis by decreasing the ratio of Bax/Bcl-2 in hippocampal neurons, and restored the abnormal secretion of inflammatory factors (IL-2, TNF-α, IL-1β, and IL-6). Moreover, the gavage of high-dose DISS can boost the expressions of CREB/BDNF. Overall, our results indicate that DISS improves cognitive function in APP/PS1 transgenic mice by inhibiting neural apoptosis and activating the CREB/BDNF signal pathway.

Possible involvement of inflammasomes on the post-stroke cognitive impairment in a mouse model of embolic cerebral infarct

Post-stroke cognitive impairment (PSCI) of the complications after stroke has been shown to be involved in brain proinflammatory cytokines such as interleukin (IL)-1β (IL-lβ) and IL-18. In the present study, we examined using acetic acid-induced embolic cerebral infarct (ECI) mice whether post-stroke inflammasome activation is involved in the development of PSCI. In behavioral tests, long-term learning and memory assessed using the passive avoidance test were impaired after ECI. On the other hand, the impairment of short-term learning and memory assessed using the Y-maze test was not observed. Furthermore, the phosphorylated α-amino-3hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit glutamate receptor 1 (GluR1) at Ser 831 and Ser 845 protein was found to be significantly decreased in the dorsal hippocampus of ECI mice. In addition, the expression levels of ionized calcium-binding adapter protein 1 (Iba1), glial fibrillary acidic protein (GFAP), apoptosis-associated speck-like protein containing a caspase recruitment domain / target of methylation-induced silencing 1 (ASC/TMS1), Caspase-1, IL-1β, IL-18 and tumor necrosis factor-α (TNF-α) were significantly increased in the dorsal hippocampus of ECI mice. These results indicate that development of PSCI after embolic cerebral infarction is due to a decrease in AMPA receptor subunit GluR1 at Ser831 and Ser845 through the inflammasome activation pathway in the dorsal hippocampus.

Neurochemical Effects of Methylphenidate and Modafinil in Ameliorating Stress-Induced Cognitive Deficits.

Chronic stressful situations result in altered monoaminergic activity of neurotransmitters, resulting in various conditions characterized by deficits in learning, memory and attention. Stimulant effects can be visualized in terms of increased cognitive abilities through enhancement of dopamine (DA) release. This study examined cognitive responses and brain DA and 5-hydroxytryptamine (5HT) levels after prolonged methylphenidate (MPH) and modafinil administration, to demonstrate their effect on stress-induced cognitive deficits in rats. Effects on cognition were evaluated by passive avoidance and water maze tests. Furthermore brain levels of DA, homovanillic acid (HVA), dihydroxyphenylacetic acid (DOPAC), 5HT and 5-hydroxyindoleacetic acid (5HIAA) were analyzed by high-performance liquid chromatography coupled with electrochemical detection. We found that both MPH and modafinil improved cognition in both restrained and unrestrained rats, as examined through water maze and passive avoidance tests. Furthermore, these substance were associated with increased brain DA and 5-HT levels. Notabily, we observed decrease in DOPAC and HVA levels, while 5-HIAA levels exhibited a slight increase. The prevention of stress-induced cognitive deficits by MPH and modafinil could be elucidated through the interaction between 5HT and DA in regulating cognitive function.

Carvacrol improved learning and memory and attenuated the brain tissue oxidative damage in aged male rats

Introduction: Aging is an unavoidable process in the body that is accompanied by impaired tissue homeostasis and various changes. Carvacrol has attracted considerable attention for its wide range of pharmacological activities. Therefore, this study attempted to explore the protective effect of carvacrol in aged rats.Materiel and methods: The aged rats were given carvacrol (15 or 30 mg/kg/day) for 4 weeks. Morris water maze and passive avoidance tests were used to determine the learning and memory abilities of the rats. The hippocampus and cortex samples were taken for biochemical analysis.Results: In comparison to young control rats, aged control rats showed learning and memory deficits. There was improvement in the Morris water navigation test and passive avoidance test performance in the treatment groups versus the aged control group. An increment in malondialdehyde (MDA) and a decrease in total thiol groups in the hippocampus and cortex samples of aged control rats in comparison to the young control group were observed. Carvacrol decreased MDA levels and increased total thiol groups in the hippocampus and cortex samples of aged rats.Conclusion: Carvacrol improved learning and memory in aged rats, probably through its anti-oxidation effects.

Improvements of Age-Related Cognitive Decline in Mice by Lactobacillus helveticus WHH1889, a Novel Strain with Psychobiotic Properties.

A gradual decline in cognitive function occurs with age. Accumulating evidence suggests that certain probiotic strains exert beneficial effects on age-related cognitive decline. Our previous study revealed that Lactobacillus helveticus WHH1889 attenuated symptoms of anxiety and depression in depressed mice via shaping the 5-hydroxytryptamine (5-HT) and 5-hydroxytryptophan (5-HTP) metabolism and gut microbial community, indicating the psychobiotic potential of WHH1889. In the present study, the effects of WHH1889 on age-related cognitive decline were investigated. WHH1889 was orally administrated (1 × 109 CFU/day) for twelve weeks in aged mice, and their cognitive behaviors, neurochemical factors, cognitive-related gene expressions, neuroinflammation, and serum tryptophan pathway-targeted metabolic profiling, as well as gut microbiome composition were assessed. WHH1889 demonstrated improvement of the cognitive behaviors via the novel object recognition test (NORT), the active shuttle avoidance test (ASAT), the Y-maze test, and the passive avoidance test (PAT). The hippocampal neuronal loss; the declined concentrations of BDNF, 5-HT, and 5-HTP; the decreased gene expressions of neurodegeneration biomarkers; and the increased production of hippocampal inflammatory cytokines in aged mice were restored by WHH1889. In addition, WHH1889 increased the 5-HT/5HTP levels and decreased the serum levels of tryptophan-derived metabolites (e.g., kynurenine, xanthurenic acid, 3-hydroxykynurenine, and 3-hydroxyanthranilic acid). Furthermore, WHH1889 was revealed to shape the gut microbiota community by reversing the relative abundances of Bacteroidota and Firmicutes. The present findings suggest that L. helveticus WHH1889 exerted cognitive improving effects on aged mice, which was associated with the modulation of 5-HT and 5-HTP metabolism and gut microbial composition. The supplementation of WHH1889 may therefore be a promising therapeutic agent for age-related cognitive deficits.