Induction Of Alzheimer's Disease Research Articles

Oral administration of liposome-encapsulated thymol could alleviate the inflammatory parameters in serum and hippocampus in a rat model of Alzheimer's disease

BackgroundNeuroinflammation is closely related to Alzheimer's Disease (AD) pathology, hence supplements with anti-inflammatory property could help attenuate the progression of AD. This study was conducted to evaluate the potential anti-inflammatory effects of liposome encapsulated thymol (LET), administered orally, in prevention of Alzheimer in a rat model by anti-inflammatory mechanisms. MethodsThe rats were grouped into six groups (n = 10 animals per group), including Control healthy (Con), Alzheimer's disease (AD) model, AD model treated with free thymol in 40 and 80 mg/kg body weight (TH40 and TH80), AD model treated with LET in 40 and 80 mg/kg of body weight (LET40 and LET80). The behavioral response of step through latency (Passive Avoidance Test), concentrations of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) and cyclooxygenase-2 (COX-2) and brain-derived neurotrophic factor (BDNF) were assessed in serum and hippocampus. ResultsThe results showed that significant increase in concentrations of IL-1β (P = 0.001), IL-6 (P = 0.001), TNF-α (P = 0.001) and COX-2 (P = 0.001) in AD group compared with healthy control rats. AD induction significantly reduced step through latency and revealed deficits in passive avoidance performance. The results also showed the treatment with free thymol especially in higher concentrations and also LTE could decrease serum concentrations of IL-1β (P < 0.05), IL-6 (P < 0.05), TNF-α (P < 0.05), and COX-2 (P < 0.05) and increase BDNF (P < 0.05) compared with control Alzheimer rats in hippocampus and serum. There were also significant correlations between serum and hippocampus concentrations of IL-1β (r2 = 0.369, P = 0.001), IL-6 (r2 = 0.386, P = 0.001), TNF-α (r2 = 0.412, P = 0.001), and COX-2 (r2 = 0.357, P = 0.001). It means a closed and positive relation between serum and hippocampus concentrations of IL-1β, IL-6, TNF-α, and COX-2. ConclusionsLET demonstrates its ability to attenuate neuroinflammatory reaction in AD model through suppression of IL-1β, IL-6, and TNF-α and COX-2 indicators. Hence, it can ameliorate AD pathogenesis by declining inflammatory reaction.

Effects of Cycloastragenol on Alzheimer's Disease in Rats by Reducing Oxidative Stress, Inflammation, and Apoptosis.

As individuals age, they may develop Alzheimer's disease (AD), which is characterized by difficulties in speech, memory loss, and other issues related to neural function. Cycloastragenol is an active ingredient of Astragalus trojanus and has been used to treat inflammation, aging, heart disease, and cancer. This study aimed to explore the potential therapeutic benefits of cycloastragenol in rats with experimentally induced AD. Moreover, the underlying molecular mechanisms were also evaluated by measuring Nrf2 and HO-1, which are involved in oxidative stress, NFκB and TNF-α, which are involved in inflammation, and BCL2, BAX, and caspase-3, which are involved in apoptosis. Sprague-Dawley rats were given 70 mg/kg of aluminum chloride intraperitoneally daily for six weeks to induce AD. Following AD induction, the rats were given 25 mg/kg of cycloastragenol daily by oral gavage for three weeks. Hippocampal sections were stained with hematoxylin/ eosin and with anti-caspase-3 antibodies. The Nrf2, HO-1, NFκB, TNF-α, BCL2, BAX, and caspase-3 gene expressions and protein levels in the samples were analyzed. Cycloastragenol significantly improved rats' behavioral test performance. It also strengthened the organization of the hippocampus. Cycloastragenol significantly improved behavioral performance and improved hippocampal structure in rats. It caused a marked decrease in the expression of NFκB, TNF-α, BAX, and caspase-3, which was associated with an increase in the expression of BCL2, Nrf2, and HO-1. Cycloastragenol improved the structure of the hippocampus in rats with AD. It enhanced the outcomes of behavioral tests, decreased the concentration of AChE in the brain, and exerted antioxidant and anti-inflammatory effects. Antiapoptotic effects were also noted, leading to significant improvements in cognitive function, memory, and behavior in treated rats.

Cacao consumption improves passive avoidance memory impairment in a rat model of Alzheimer's disease: the role of hippocampal synaptic plasticity and oxidative stress.

Introduction: Alzheimer's disease (AD) causes progressive loss of cognitive function and synaptic plasticity, which is the most common form of dementia. The present study was designed to scrutinize the effects of cacao on passive avoidance memory function and to identify the roles of hippocampal synaptic plasticity and oxidative stress in an AD rat model induced by unilateral intracerebroventricular (UICV) injection of amyloid-beta (Aβ). Methods: Oral administration of cacao (500 mg/kg/ day) was given for 2 consecutive months. A memory retention test was conducted 24 h after passive avoidance training was completed. Subsequently, the amplitude of population spike (PS) and slope of field excitatory postsynaptic potentials (fEPSPs) were assessed at hippocampal long-term potentiation (LTP) in perforant pathway-dentate gyrus (PP-DG) synapses. Moreover, total thiol group (TTG) and malondialdehyde (MDA) concentrations were evaluated in the plasma. Furthermore, compact Aβ plaques were detected in the hippocampal DG by performing Congo red staining. Results: As a result of AD induction, passive avoidance memory was impaired; also, reduced fEPSP slopes, PS amplitudes, and content of TTG, and increase in MDA levels in the rats were observed. In contrast, cacao treatment ameliorated passive avoidance memory impairment, improved hippocampal LTP impairment, modulated oxidative-antioxidative status, and delayed Aβ plaques production in AD rats. Disscussion: Conclusively, cacao alleviates Aβ-induced cognitive deficit, probably by the amelioration of hippocampal LTP impairment, modulation of oxidative-antioxidative status, and inhibition of Aβ plaque accumulation.

The effect of 8 weeks of interval training combined with the consumption of cineole, linalool, and bourbonene on MAPK/Arc gene expression and learning in rats with Alzheimer’s disease

Background and aims: This research aimed to investigate the effect of 8 weeks of interval training and the use of cineole, linalool, and bourbonene on MAPK/Arc gene expression and learning in Alzheimer’s disease (AD) rats. Methods: In this experimental study, 40 AD rats were randomized into eight groups, including (1) control, (2) AD, (3) AD+aerobic training (AT), (4) AD+linalool, cineole, and bourbonene (LCB), (5) AD+AT+LCB, (6) AT+AD, (7) LCB+AD, and (8) AT+LCB+AD. AD was induced by injecting amyloid-beta (Aβ1)-42 into the hippocampus of rats. The interval training protocol was performed five days per week for eight weeks before and after AD induction. Linalool at a concentration of 25 mg/kg, cineole at a concentration of 10 µM, and β-bourbonene at a concentration of 10 µg/mL were used for eight weeks. One-way analysis of variance was used for between-group comparisons, and Tukey’s test was used for pairwise comparisons at P≤0.05. Results: AD induction caused a significant decrease in MAPK/Arc gene expression in hippocampal tissue (P=0.001). Interval exercise and consumption of three herbal drugs significantly increased gene expression of Arc (P=0.001) and MAPK (P=0.001). AD induction decreased learning (P=0.001). Interval exercise and consumption of three herbal medicines caused a significant increase in learning (P=0.001). Conclusion: Interval exercise and using three herbal medicines have more favorable effects on improving MAPK/Arc gene expression and learning in AD than each alone.

Evaluation of Neuroprotective effect of Cassia occidentalis L. against Colchicine Induced Memory Impairment in Wistar Rats

Background: Alzheimer’s disease (AD) is a progressive neurological disorder that develops with aging. Objective: In this research, we have examined the anti - Alzheimer’s effect of ethanolic extract from roots of Cassia occidentalis L. on colchicine-induced Alzheimer’s in Wistar rats Methods: Ethanolic extract was obtained and spectroscopic, chromatography analysis was performed. Acute toxicity studies using Organization of Economic Co-operation and Development (OECD) Guidelines 423 were performed to examine and make sure that there were no signs of toxic effects. The induction of AD was done using colchicine which leads to symptoms like neurotoxicity, neuroinflammation, and neurodegeneration. In this experiment, a thorough analysis of body weight, behavioral parameters, locomotor activity, and biochemical evaluation was performed to estimate the medicinal properties of Cassia occidentalis L in treating Alzheimer’s disease. Results: Pharmacognostic analysis showed the presence of vascular bundles, starch grains, fibers, calcium oxalate crystals, elongated parenchyma, and collenchyma mucilage as shown in the supplementary files. Locomotor activity, Escape latency time, Conditioned avoidance response, and Transfer latency were improved with treatment. Interleukin- 6 (IL - 6) levels were reduced significantly in the Colchicine + 200 Cassia mg/kg group (739.2 ± 0.37 pg/ml) than in the Colchicine Group (850.6±0.40 pg/ml). Tumor necrosis factor (TNF-α) was decreased in the Colchicine + 200 Cassia mg/kg Group (1030.93±0.51 pg/ml) than in the Colchicine Group (1455.06±1.25 pg/ml). A significant decrease in total protein level was observed in the Colchicine Group (2.52±0.10 mg/ml), (3.33±0.90 mg/ml) as compared to Colchicine + 200 Cassia mg/kg Group (5.27±0.09 mg/ml, (5.01±0.10 mg/ml) respectively, in the Hippocampus and Entorhinal cortex. The levels of antioxidant enzymes such as Catalase (CAT), Serum superoxide dismutase (SOD), Reduced glutathione (GSH) and Malondialdehyde (MDA) were measured. When compared to the Colchicine Group (7.33±0.16 nM/ mg, the MDA level was lower in the Colchicine + 100 Cassia mg/kg Group (3.20±0.01 nM/ mg). The level of CAT in Colchicine + 200 Cassia mg/kg Group (7.01±0.03 μmoles of H2O2/mg of protein) was seen to be increased when compared to Colchicine Group (3.32 ± 0.17 μmoles of H2O2/mg of protein). The level of SOD in Colchicine + 200 Cassia mg/kg Group (7.43±0.02 U mg -1 of protein) was seen to be increased when compared with Colchicine Group (4.55±0.03 U mg -1 of protein). The level of GSH in Colchicine + 200 Cassia mg/kg Group (10.07±0.19 nM/mg -1 of protein) was increased when compared with the Colchicine Group (5.82±0.11nM/mg -1 of protein). Histopathology of the Hippocampus and Entorhinal cortex showed diminished amyloid plaques, and neurodegeneration in the treatment groups Conclusion: The present study showed that ethanolic extract from the roots of Cassia occidentalis L. At 100 and 200 mg/kg doses in Wistar rats improved memory damage, by reducing oxidative stress. Levels of the antioxidant enzymes as CAT, and SOD, GSH were increased and MDA was decreased. The cytokine levels in the serum of Wistar rats of IL-6 level and TNF-α level were reduced significantly. Estimation of total protein level was found to be increased. It restored neuronal degeneration in the Hippocampus, and Entorhinal cortex and reduced oxidative stress. This suggests that the ethanolic extract of Cassia occidentalis L. could be an effective therapeutic treatment for neurodegenerative diseases like AD.

Combined Donepezil with Astaxanthin via Nanostructured Lipid Carriers Effective Delivery to Brain for Alzheimer's Disease in Rat Model.

Donepezil (DPL), a specific acetylcholinesterase inhibitor, is used as a first-line treatment to improve cognitive deficits in Alzheimer's disease (AD) and it might have a disease modifying effect. Astaxanthin (AST) is a natural potent antioxidant with neuroprotective, anti-amyloidogenic, anti-apoptotic, and anti-inflammatory effects. This study aimed to prepare nanostructured lipid carriers (NLCs) co-loaded with donepezil and astaxanthin (DPL/AST-NLCs) and evaluate their in vivo efficacy in an AD-like rat model 30 days after daily intranasal administration. DPL/AST-NLCs were prepared using a hot high-shear homogenization technique, in vitro examined for their physicochemical parameters and in vivo evaluated. AD induction in rats was performed by aluminum chloride. The cortex and hippocampus were isolated from the brain of rats for biochemical testing and histopathological examination. DPL/AST-NLCs showed z-average diameter 149.9 ± 3.21 nm, polydispersity index 0.224 ± 0.017, zeta potential -33.7 ± 4.71 mV, entrapment efficiency 81.25 ±1.98% (donepezil) and 93.85 ±1.75% (astaxanthin), in vitro sustained release of both donepezil and astaxanthin for 24 h, spherical morphology by transmission electron microscopy, and they were stable at 4-8 ± 2°C for six months. Differential scanning calorimetry revealed that donepezil and astaxanthin were molecularly dispersed in the NLC matrix in an amorphous state. The DPL/AST-NLC-treated rats showed significantly lower levels of nuclear factor-kappa B, malondialdehyde, β-site amyloid precursor protein cleaving enzyme-1, caspase-3, amyloid beta (Aβ1‑42), and acetylcholinesterase, and significantly higher levels of glutathione and acetylcholine in the cortex and hippocampus than the AD-like untreated rats and that treated with donepezil-NLCs. DPL/AST-NLCs showed significantly higher anti-amyloidogenic, antioxidant, anti-acetylcholinesterase, anti-inflammatory, and anti-apoptotic effects, resulting in significant improvement in the cortical and hippocampal histopathology. Nose-to-brain delivery of DPL/AST-NLCs is a promising strategy for the management of AD.

Minocycline effects on memory and learning impairment in the beta-amyloid-induced Alzheimer’s disease model in male rats using behavioral, biochemical, and histological methods

Alzheimer’s disease (AD), as an advanced neurodegenerative disease, is characterized by the everlasting impairment of memory, which is determined by hyperphosphorylation of intracellular Tau protein and accumulation of beta-amyloid (Aβ) in the extracellular space. Minocycline is an antioxidant with neuroprotective effects that can freely cross the blood-brain barrier (BBB). This study investigated the effect of minocycline on the changes in learning and memory functions, activities of blood serum antioxidant enzymes, neuronal loss, and the number of Aβ plaques after AD induced by Aβ in male rats. Healthy adult male Wistar rats (200–220g) were divided randomly into 11 groups (n = 10). The rats received minocycline (50 and 100 mg/kg/day; per os (P.O.)) before, after, and before/after AD induction for 30 days. At the end of the treatment course, behavioral performance was measured by standardized behavioral paradigms. Subsequently, brain samples and blood serum were collected for histological and biochemical analysis. The results indicated that Aβ injection impaired learning and memory performances in the Morris water maze test, reduced exploratory/locomotor activities in the open field test, and enhanced anxiety-like behavior in the elevated plus maze. The behavioral deficits were accompanied by hippocampal oxidative stress (decreased glutathione (GSH) peroxidase enzyme activity and increased malondialdehyde (MDA) levels in the brain (hippocampus) tissue), increased number of Aβ plaques, and neuronal loss in the hippocampus evidenced by Thioflavin S and H&E staining, respectively. Minocycline improved anxiety-like behavior, recovered Aβ-induced learning and memory deficits, increased GSH and decreased MDA levels, and prevented neuronal loss and the accumulation of Aβ plaques. Our results demonstrated that minocycline has neuroprotective effects and can reduce memory dysfunction, which are due to its antioxidant and anti-apoptotic effects.

The Possible Effects of Vitamin D3 on AlCl3-Induced Histological and Morphometric Alterations of Adult Male Albino Rat Hippocampus.

Alzheimer's disease (AD) is a challenging neurodegenerative disease, and Vitamin D was proved to have neuroprotective effects. This study was conducted to evaluate the potential neuroprotective effects of Vitamin D3 supplementation on AlCl3-induced AD rat model in different hippocampal subregions (CA1, CA2, and CA3). It also aimed to compare the protective effects of protective versus therapeutic effects of Vitamin D3 regiments on the number of degenerated neurons and the neuronal layer thickness. Twenty-four adult male Albino Wister rats were sorted into GI: control; GII: AlCl3-AD model (100 mg/kg) orally for 42 days; GIII: Rats were co-treated with AlCl3 (as GII) and Vitamin D3 (400 IU/kg/day) orally for 42 days; GIV: Rats were treated with AlCl3 for 42 days then with Vitamin D3 for further 2 weeks. Sagittal sections (5 μ) from paraffin-processed brains previously fixed in 10% neutral-buffered formalin were stained with hematoxylin and eosin to evaluate the thickness and number of degenerated neurons in the hippocampal CA1, CA2, and CA3 subregions. The results of this study were expressed as mean ± standard deviation and analyzed by using IBM SPSS Statistics for Windows, version 23 (IBM SPSS, IBM Corp., Armonk, N.Y., USA). P < 0.05 was considered statistically significant. Vitamin D3 supplementations modulated the degenerative changes observed in the hippocampus of AD rat model. In all hippocampal subregions, the thickness was higher in rats treated with Vitamin D3 after the AD induction than rats treated with Vitamin D3 during AD induction. However, this increase was only significant in CA2. Comparison of the number of degenerated neurons between both groups treated with Vitamin D3 revealed that in CA1, the number of degenerated neurons did not statistically differ between the two groups. However, it was insignificantly lower in CA2 in rats treated with Vitamin D3 after the AD induction, and in CA3, it was insignificantly lower in rats treated with Vitamin D3 during the AD induction. Vitamin D3 was found to be effective in ameliorating histological and morphometric alterations in AlCl3-induced AD in rat model and could be proposed as both preventive and therapeutic supplements in high-risk AD patients.

Effects of diverse Types of Toxoplasma gondii on the outcome of Alzheimer's disease in the rat model.

Toxoplasma gondii has lifelong persistence in the brain and its cysts can affect gene expression and change diverse biological functions of neurons. Many studies indicated T. gondii infection as a risk factor for the development of behavioral changes and neurodegenerative diseases such as Alzheimer's disease (AD), although the etiopathogenetic link between them has not been exactly elucidated. The current study aimed to examine the effects of chronic toxoplasmosis infection with Types I, II, and III strains (RH, PRU, and VEG) alone and in combination on cognitive impairments and neuronal death in the Aβ1-42-induced rat model of Alzheimer's disease. In the chronic toxoplasmosis phase, Alzheimer's induction was conducted by injecting Aβ1-42 oligomers into the rat brain hippocampus. Behavioral tests were conducted 10 days after the AD induction. Real-time PCR was performed to evaluate T. gondii parasite burden by amplification of the B1 gene. Cytokines IL-1β, TNF-α, and IL-10 were assayed in brain tissue supernatant using ELISA. Also, histopathological examinations were conducted to calculate inflammatory changes and neuronal death in the brain. Our findings showed that chronic toxoplasmosis infection with PRU reduces cognitive disorders, while the RH strain of T. gondii plays a destructive role and aggravates cognitive impairments in AD. Also, infection with a combination of PRU and VEG strains significantly improved spatial learning and memory impairments in Alzheimer's rat model. Histopathological findings also confirmed the results of behavioral tests, so that in AβPRU and AβPRU+VEG groups, neuronal death and infiltration of inflammatory cells were negligible and significantly less than in Alzheimer's and AβRH groups. Our findings indicate that chronic toxoplasmosis infection with PRU strain alone, also in combination with VEG strain can significantly improve cognitive disorders in AD rats, while RH strain plays a destructive role in AD pathogenesis.

Antioxidant properties of Trifolium resupinatum and its therapeutic potential for Alzheimer's disease.

Alzheimer's disease (AD) is the most common cause of dementia and is characterized by a progressive deterioration in cognitive function, which typically begins with impairment in memory. Persian clover (Trifolium resupinatum) is an annual plant found in central Asia. Due to its contents (high flavonoid and isoflavones), extensive researches have been done on its therapeutic properties, such as multiple sclerosis (MS) treatment. In this study, we investigate the neuroprotective effects of this plant on Streptozotocin (STZ)-induced AD in rats. This research aimed to evaluate the neuroprotective effect of Trifolium resupinatum on the spatial learning and memory, superoxide dismutase (SOD), expressions of β amyloid 1-42 (Ab 1-42 ), and b amyloid 1-40 (Ab 1-40 ) in the hippocampus of STZ-induced Alzheimer rats. Our data showed that Trifolium resupinatum extract administration for two weeks before and one week after AD induction significantly improves maze escape latency ( p = 0.027, 0.001 and 0.02 in 100, 200, and 300 mg of the extract, respectively) and maze retention time ( p = 0.003, 0.04 and 0.001 in 100, 200, and 300 mg of the extract, respectively). Also, the administration of this extract significantly increases the SOD levels from 1.72+0.20 to 2.31+0.45 ( p = 0.009), 2.48+0.32 ( p = 0.001) and 2.33+0.32 ( p = 0.007) and decreases the expressions of Ab 1-42 ) ( p = 0.001 in all concentrations of the extract) and Ab 1-40 ) ( p = 0.001 in all concentrations of the extract) in the rat's hippocampus. This study suggests that the alcoholic extract of Trifolium resupinatum has anti-Alzheimer and neuroprotective effects on rats.

Brain Targeting of Citicoline Sodium via Hyaluronic Acid-Decorated Novel Nano-Transbilosomes for Mitigation of Alzheimer's Disease in a Rat Model: Formulation, Optimization, in vitro and in vivo Assessment.

Alzheimer's disease (AD) is one of the furthermost advanced neurodegenerative disorders resulting in cognitive and behavioral impairment. Citicoline sodium (CIT) boosts the brain's secretion of acetylcholine, which aids in membrane regeneration and repair. However, it suffers from poor blood-brain barrier (BBB) permeation, which results in lower levels of CIT in the brain. This study targeted to encapsulate CIT into novel nano-platform transbilosomes decorated with hyaluronic acid CIT-HA*TBLs to achieve enhanced drug delivery from the nose to the brain. A method of thin-film hydration was utilized to prepare different formulae of CIT-TBLs using the Box-Behnken design. The optimized formula was then hyuloranated via integration of HA to form the CIT-HA*TBLs formula. Furthermore, AD induction was performed by aluminum chloride (Alcl3), animals were allocated, and brain hippocampus tissue was isolated for ELISA and qRT-PCR analysis of malondialdehyde (MDA), nuclear factor kappa B (NF-kB), and microRNA-137 (miR-137) coupled with immunohistochemical amyloid-beta (Aβ1-42) expression and histopathological finding. The hyuloranated CIT-HA*TBLs formula, which contained the following ingredients: PL (300 mg), Sp 60 (43.97 mg), and SDC (20 mg). They produced spherical droplets at the nanoscale (178.94 ±12.4 nm), had a high entrapment efficiency with 74.92± 5.54%, had a sustained release profile of CIT with 81.27 ±3.8% release, and had ex vivo permeation of CIT with 512.43±19.58 μg/cm2. In vivo tests showed that CIT-HA*TBL thermogel dramatically reduces the hippocampus expression of miR-137 and (Aβ1-42) expression, boosting cholinergic neurotransmission and decreasing MDA and NF-kB production. Furthermore, CIT-HA*TBLs thermogel mitigate histopathological damage in compared to the other groups. Succinctly, the innovative loading of CIT-HA*TBLs thermogel is a prospectively invaluable intranasal drug delivery system that can raise the efficacy of CIT in Alzheimer's management.

The Effect of Aerobic Training before Alzheimer’s Induction on the Expression of Calcineurin and Ca2+/Calmodulin-dependent Protein Kinase II Gene in the Hippocampus of Rats with Alzheimer’s Disease

Background and Objectives Regular aerobic exercise improves learning, memory, and cognitive and Synaptic Plasticity in Alzheimer’s disease (AD) patients. The aim of this study was to evaluate the levels of calcineurin and Ca2+/calmodulin-dependent protein kinase II mRNA after four weeks of aerobic training exercises and before AD induction in the hippocampus of male Wistar rats. Subjects and Methods Thirty 8-week-old rats with an average weight of 195±20 g were initially randomly divided into two groups of aerobic exercise or rest for four weeks. Then, each group was divided into three groups of AD, sham, and injection. Then, 48 hours after the last training session, Aβ1-42, or DMSO was injected into the hippocampus. Finally, after the isolation of the hippocampus, CaN mRNA and CaMKII mRNA levels were measured. Results The results of this study showed that there was a significant difference between the groups in mRNA CaN and CaMKII mRNA levels (P&lt;0.05). The results showed that aerobic exercise and AD pre-induction had a significant effect on increasing calcineurin and Ca2+/calmodulin-dependent protein kinase II levels. Conclusion Overall, the findings of the present study showed that four weeks of aerobic training improves the molecular signaling of neuroplasticity in AD rats.

Changes in Some Observational Cardiac Parameters and Cardiac PGC1-α Expression Following Eight Weeks of Endurance Training and Saffron Consumption in Animal Models of Alzheimer’s Disease

Introduction: The link between Alzheimer’s disease (AD) and heart disease has recently been reported. Previous studies have reported the beneficial role of endurance training (ET) and saffron (Sa) on the heart and nervous system health, but their interactive effect is not yet well known. Therefore, the aim of this study was to determine changes in some observational cardiac parameters and cardiac PGC1-α expression after 8 weeks of ET and Sa consumption in animal models of AD. Methods: In this experimental trial, 40 rats with AD (by intraperitoneal injection of 8 mg/kg neurotoxin trimethyltin) were divided into (1) AD, (2) sham (Sh), (3) Sa, (4) ET, and (5) ET+Sa groups. Additionally, to evaluate the effect of AD induction on the research variables, 8 healthy rats were included in the healthy control (HC) group. Groups 4 and 5 ran for 8 weeks, three 15-30 minute sessions per week at a speed of 20-15 m/min. Groups 3 and 5 received 25 mg/ kg aqueous extract of Sa peritoneally each day. To analyze the data, dependent samples t test, one-way analysis of variance and Tukey’s post hoc test, analysis of covariance with Bonferroni’s post hoc test in SPSS version 22.0 were used (P≥0.05). Results: In the Sa and ET+Sa groups, heart weight, heart weight to body weight ratio, and cardiac PGC1-α expression were higher and the body weight of these groups was significantly lower compared with the AD group (P≤0.05). Moreover, in the ET group, heart weight was higher than body weight and total body weight was lower compared to the AD group (P≤0.05). Conclusion: It seems that Sa and ET+Sa interaction improve heart function and some parameters related to heart health by increasing PGC1-α expression, but the effect of training depends on its type and intensity, which should be further studied.

The effect of minocycline on beta-amyloid-induced memory and learning deficit in male rats: A behavioral, biochemical, and histological study

ObjectivesMinocycline hydrochloride is a semi-synthetic, second-generation tetracycline with neuroprotective, neurorestorative, anti-amyloidogenic, anti-inflammatory, antioxidant, and anti-apoptotic properties. The present study was designed to investigate the potential protective effects of minocycline against beta-amyloid (Aβ)-induced Alzheimer’s disease (AD), recognition memory decline, and the possible involved anti-apoptotic mechanisms. MethodsThe rats were treated with minocycline (50 and 100 mg/kg/day; P.O.) after AD induction for 30 days. Behavioral functions were assessed by employing standard behavioral tests, including novel object recognition (NOR) and passive avoidance learning (PAL) tasks. Then, total antioxidant capacity (TAC) and total oxidant status (TOS) were measured in blood serum using ELISA kits. Apoptosis and the number of Aβ plaques were examined by the TUNEL and Congo red staining, respectively. ResultsTreatment of Aβ rats with minocycline improved memory deficit in the PAL task and a decline in recognition memory in the NOR test. Minocycline at 50 and 100 mg/kg significantly reduced the TOS levels and increased the TAC levels (P < 0.0001). Also, minocycline at 50 and 100 mg/kg reduced the apoptotic index in the hippocampus of Aβ rats. After Congo red staining, the minocycline group showed improved cell morphology and markedly fewer Aβ plaques. ConclusionsMinocycline reduced memory and learning deficit in behavioral experiments after Aβ injection, which may be due to its anti-inflammatory and anti-apoptotic effects.

Controversial Effects of Diverse Types of Toxoplasma gondii on the Anxiety-like Behavior and Cognitive Impairments in the Animal Model of Alzheimer's Disease

Background: Toxoplasma gondii is a neurotropic parasite with lifelong persistence in the host brain. Many researchers suggested toxoplasmosis as a risk factor for the development of Alzheimer's disease (AD); however, the link between them has not been fully elucidated. Objectives: The present study was designed to investigate the effects of chronic toxoplasmosis infection with Types I (RH), II (PRU), and III (VEG) strains alone and in combination on cognitive impairments in Alzheimer's rat model. Methods: Seven months after the inoculation of the strains, AD was induced bilaterally in rats by injecting human amyloid beta 1-42 (Aβ1-42) peptide into the brain hippocampus. Behavioral tests, including the elevated plus maze (EPM) and Morris water maze (MWM) were conducted 10 days after the AD induction. Results: Our findings showed that chronic infection with RH strain increased anxiety-like behavior in the Alzheimer's rats in the EPM. In agreement with EPM findings, rats infected with the RH strain exacerbated spatial learning disorders in the MWM test; however, it did not affect the spatial memory. Conversely, infection with the PRU strain significantly enhanced spatial learning without being able to improve memory impairments in the Alzheimer's rat model. Improvement in spatial learning and memory impairments were also observed in rats infected with PRU and VEG strains in combination. Conclusions: Taken together, our findings suggest that chronic infection with PRU strain, as well as PRU and VEG strains in combination, can significantly improve cognitive deficits induced by Aβ1-42 in Alzheimer's rats, while RH strain plays a detrimental role in AD pathogenesis.

Does SARS-CoV-2 affect neurodegenerative disorders? TLR2, a potential receptor for SARS-CoV-2 in the CNS.

The coronavirus (COVID-19) pandemic, caused by severe acute respiratory system coronavirus 2 (SARS-CoV-2), has created significant challenges for scientists seeking to understand the pathogenic mechanisms of SARS-CoV-2 infection and to identify the best therapies for infected patients. Although ACE2 is a known receptor for the virus and has been shown to mediate viral entry into the lungs, accumulating reports highlight the presence of neurological symptoms resulting from infection. As ACE2 expression is low in the central nervous system (CNS), these neurological symptoms are unlikely to be caused by ACE2-virus binding. In this review, we will discuss a proposed interaction between SARS-CoV-2 and Toll-like receptor 2 (TLR2) in the CNS. TLR2 is an innate immune receptor that recognizes exogenous microbial components but has also been shown to interact with multiple viral components, including the envelope (E) protein of SARS-CoV-2. In addition, TLR2 plays an important role in the pathogenesis of neurodegenerative diseases such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). Based on these observations, we hypothesize that TLR2 may play a critical role in the response to SARS-CoV-2 infiltration in the CNS, thereby resulting in the induction or acceleration of AD and PD pathologies in patients.

Antioxidant Effect of Swimming Training and Royal Jelly Consumption in the Hippocampus Tissue of Rats With Alzheimer’s Disease

Background: As an age-related disease, Alzheimer’s disease (AD) is characterized by memory loss and cognitive impairment. Although oxidative stress factors increase in AD, exercise and nutrition can have protective and antioxidant effects. This study aimed to explore the antioxidant effects of swimming training (ST) and royal jelly (RJ) consumption in the hippocampus tissue of rats with AD. Methods: In this experimental study, 20 rats with AD were selected and divided into four groups, including control, ST, RJ, and ST+RJ. In order to probe the effects of AD induction on superoxide dismutase (SOD) and glutathione peroxidase (GPx), five healthy rats were assigned into the healthy control group. For eight weeks, the ST groups performed ST three times per week (5 minutes in the first week to 60 minutes in the last week), and the RJ groups received 100 mg/kg RJ per day. The Shapiro-Wilk, independent samples t test, and two-way analysis of variance (ANOVA) tests were used to analyze the findings (P≤0.05). Results: AD induction had a significant effect on increasing SOD (P=0.04) and decreasing GPx (P=0.001). Also, ST (P=0.001) and RJ (P=0.01) had a significant effect on increasing GPx; ST (P=0.001) and RJ (P=0.001) had a significant effect on decreasing SOD. Furthermore, ST with RJ had an interactive effect on increasing GPx (P=0.03) and decreasing SOD (P=0.001). Conclusion: In general, ST and RJ appear to simultaneously improve the gene expression of antioxidants in the hippocampus tissue of AD rats. In addition, the antioxidant effects of ST were more favorable than those of RJ. It appears that different doses of RJ should also be considered.

Ameliorative Effect of Probiotic-Fermented Milk and Costus Extract in Alzheimer’s Disease Model Induced by D-Galactose and Aluminum Chloride

Alzheimer’s disease (AD) is a neurodegenerative disease associated with memory and cognitive dysfunction and is the main reason of dementia worldwide. The present research aimed to evaluate the protective effect of administration of probiotic-fermented milk and costus extract against AD in rats. Total phenolic content (TPC), total flavonoids (TF) and antioxidants activity (AA) of costus extracts were studied. The study included 40 rats divided into five groups. Group 1 and 2 served as normal control and AD control, respectively. Groups 3 and 4 were given daily oral dose of costus extract (100 and 200mg/KG RBW), while group 5 was given probiotic-fermented milk (1 ml/rat/day). AD was induced in rats by intraperitoneally (i.p.) injection of D-galactose and aluminium chloride for 21 days. Hippocampal gene expression of PI3K and Akt, biochemical, nutritional and histopathological studies were evaluated in all rats' groups. Microflora of fecal samples from cecum and colon were studied in group 1, 2 and 5. Costus root extract showed 98% AA and contains TPC and TF as 378.1 mg GAE/g and 275.3 mg/g extract, respectively. Induction of AD in rats led to reduction of mRNA level of PI3K and Akt in hippocampal of rats, also elevation of inflammatory and oxidative stress markers in association with significant elevation of acetylcholinesterase activity were observed. The results revealed relevant new visions towards the influences of probiotic-fermented milk and costus extract on cognitive function through reduction of neurofibrillary tangles formations, regulation of hippocampal gene expression of PI3K and Akt, inflammatory and oxidative stress markers. Conclusion: Administration of probiotic-fermented milk and costus extract have a promising effect on cognitive function through reduction of neurofibrillary tangles formation, regulation of hippocampal gene expression of PI3K and Akt, inflammatory and oxidative stress markers. The present results suggested that intake of probiotic-fermented milk had a beneficial effect on the composition of cecum and colon flora. Probiotic-fermented milk was the most effective for prevention of AD in the present study.

High Dietary Iron Has a Greater Impact on Brain Iron Homeostasis and Cognitive Function in Old Compared with Young C57BL/6J Male Mice

BackgroundBrain iron accumulation is a feature of Alzheimer disease (AD) but whether a chronic dietary iron overload contributes to AD induction is unknown. We previously showed that young mice fed a high iron diet did not display cognitive impairment despite the AD pathological markers in hippocampus. ObjectivesWe aim to compare the impact of high dietary iron on brain pathologic changes and cognitive function in young and old mice. MethodsMale C57BL/6J mice at 1 mo and 13 mo of age were fed with either a control diet (66 mg Fe/kg; Young-Ctrl and Old-Ctrl) or a high iron diet (14 g Fe/kg; Young-High Fe and Old-High Fe) for 7 mo, and outcomes were evaluated at 8 mo and 20 mo of age. Iron concentrations in brain regions were measured by atomic absorption spectrophotometry. Perls's Prussian blue staining and amyloid-β (Aβ) immunostaining were performed. Protein expression in the cerebral cortex and hippocampus was determined by immunoblotting. Superoxide dismutase activity and malondialdehyde concentration were examined. Cognitive functions were tested with the Morris water maze system. Two-factor ANOVA was used to analyze most data. ResultsCompared with Old-Ctrl mice, Old-High Fe mice showed significantly higher iron concentrations in cerebral cortex (60% higher), cerebellum (60% higher), and hippocampus (90% higher), paralleled by lower superoxide dismutase activity and greater malondialdehyde concentration in cerebral cortex and hippocampus and worse cognitive function. In contrast, these variables did not significantly differ between the 2 young groups. Nevertheless, ferritin, phospho-tau, and Aβ1–42 expression in hippocampus and ferritin and Aβ1–42 expression in cerebral cortex were induced by the high iron diet irrespective of the age of mice (40–200% greater). ConclusionsHigh dietary iron induced cognitive defects in old mice but not young mice, suggesting that elderly people should avoid consuming abnormally high concentrations of iron.

Antibiotic-induced gut microbiota depletion from early adolescence exacerbates spatial but not recognition memory impairment in adult male C57BL/6 mice with Alzheimer-like disease

Gut microbiota dysbiosis is associated with cognitive dysfunctions and Alzheimer’s disease (AD). This study set out to better understand the relationship between gut microbiota depletion and cognitive abilities in mice with or without Alzheimer-like disease. Male C57BL/6 mice from early adolescence received an antibiotic cocktail, and then in adulthood, animals were subjected to a stereotaxic surgery to induce Alzheimer-like disease using amyloid-beta (Aβ) 1–42 microinjection. To assess cognitive functions in mice, three behavioural tests including the Y maze, object recognition, and Morris water maze were used. We also measured brain-derived-neurotrophic factor (BDNF), tumour-necrosis factor (TNF)-α, interleukin (IL)-6, and Aβ42 in the brain. Our findings showed that antibiotics treatment impaired object recognition memory, whereas did not alter spatial memory in healthy mice. Antibiotics treatment in mice significantly exacerbated spatial memory impairment following the induction of AD in both the Y maze and Morris water maze test. There were significant correlations between these behavioural tests. In addition, healthy animals treated with antibiotics displayed a significant reduction in brain IL-6. We observed that antibiotics treatment significantly decreased both cytokines TNF-α and IL-6 in the brain of AD-induced mice. However, no alterations were found in brain BDNF levels following both antibiotics treatment and AD induction. These findings show that antibiotic-induced gut microbiota depletion from early adolescence to adulthood can impair cognitive abilities in mice with or without Alzheimer-like disease. Overall, this study suggests that gut microbiota manipulation from early adolescence to adulthood may adversely affect the normal development of cognitive functions.