lignans and Memory-Disorders

Multi-target drugs, such as the cocktail therapy used for treating AIDS, often show stronger efficacy than single-target drugs in treating complicated diseases. This review will focus on clausenamide (clau), a small molecule compound originally isolated from the traditional Chinese herbal medicine, Clausenalansium. The finding of four chiral centers in clau molecules predicted the presence of 16 clau enantiomers, including (-)-clau and (+)-clau. All of the predicted enantiomers have been successfully synthesized via innovative chemical approaches, and pharmacological studies have demonstrated (-)-clau as a eutomer and (+)-clau as a distomer in improving cognitive function in both normal physiological and pathological conditions. Mechanistically, the nootropic effect of (-)-clau is mediated by its multi-target actions, which include mild elevation of intracellular Ca(2+) concentrations, modulation of the cholinergic system, regulation of synaptic plasticity, and activation of cellular and molecular signaling pathways involved in learning and memory. Furthermore, (-)-clau suppresses the pathogenesis of Alzheimer's disease by inhibiting multiple etiological processes: (1) beta amyloid protein-induced intracellular Ca(2+) overload and apoptosis and (2) tau hyperphosphorylation and neurodegeneration. In conclusion, the nature of the multi-target actions of (-)-clau substantiates it as a promising chiral drug candidate for enhancing human cognition in normal conditions and treating memory impairment in neurodegenerative diseases.

Topics: Animals; Dementia; Humans; Lactams; Lignans; Medicine, Chinese Traditional; Memory Disorders

Lead (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.. Sesamin 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.. The 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.. This 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.

Topics: Animals; Dioxoles; Gamma Rhythm; Hippocampus; Lead; Lignans; Maze Learning; Memory Disorders; Rats

Arctigenin (Arc) is a phenylpropanoid dibenzylbutyrolactone lignan in Arctium lappa L, which has been widely applied as a traditional Chinese herbal medicine for treating inflammation. In the present study, we explored the neuroprotective effect and the potential mechanisms of arctigenin against LPS-evoked neuroinflammation, neurodegeneration, and memory impairments in the mice hippocampus. Daily administration of arctigenin (50 mg/kg per day, i.g.) for 28 days revealed noticeable improvements in spatial learning and memory deficits after exposure to LPS treatment. Arctigenin prevented LPS-induced neuronal/synaptic injury and inhibited the increases in Abeta (Aβ) generation and the levels of amyloid precursor protein (APP) and β-site amyloid precursor protein cleavage enzyme 1 (BACE1). Moreover, arctigenin treatment also suppressed glial activation and reduced the production of proinflammatory cytokines. In LPS-treated BV-2 microglial cells and mice, activation of the TLR4 mediated NF-κB signaling pathway was significantly suppressed by arctigenin administration. Mechanistically, arctigenin reduced the LPS-induced interaction of adiponectin receptor 1 (AdipoR1) with TLR4 and its coreceptor CD14 and inhibited the TLR4-mediated downstream inflammatory response. The outcomes of the current study indicate that arctigenin mitigates LPS-induced apoptotic neurodegeneration, amyloidogenesis and neuroinflammation as well as cognitive impairments, and suggest that arctigenin may be a potential therapeutic candidate for neuroinflammation/neurodegeneration-related diseases.

Topics: Amyloid beta-Protein Precursor; Amyloid Precursor Protein Secretases; Animals; Arctium; Aspartic Acid Endopeptidases; Cognitive Dysfunction; Furans; Inflammation; Lignans; Lipopolysaccharides; Memory Disorders; Mice; Microglia; Neuroinflammatory Diseases; NF-kappa B; Toll-Like Receptor 4

Alzheimer's disease (AD) is a neurodegenerative disease, characterized by memory loss and cognitive deficits accompanied by neuronal damage and cholinergic disorders. Sesamol, a lignan component in sesame oil, has been proven to have neuroprotective effects. This research aimed to investigate the preventive effects of sesamol on scopolamine (SCOP)-induced cholinergic disorders in C57BL/6 mice. The mice were pretreated with sesamol (100 mg/kg/d, p.o.) for 30 days. Behavioral tests indicated that sesamol supplement prevented SCOP-induced cognitive deficits. Sesamol enhanced the expression of neurotrophic factors and postsynaptic density (PSD) in SCOP-treated mice, reversing neuronal damage and synaptic dysfunction. Importantly, sesamol could balance the cholinergic system by suppressing the AChE activity and increasing the ChAT activity and

Topics: Animals; Antioxidants; Cholinergic Agents; Cognition; Cognitive Dysfunction; Humans; Lignans; Maze Learning; Memory Disorders; Mice; Mice, Inbred C57BL; Nerve Growth Factors; Neuroblastoma; Neurodegenerative Diseases; Neuroinflammatory Diseases; Neuroprotective Agents; Oxidative Stress; Scopolamine; Sesame Oil

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative disorders characterized by memory deficits. Although no drug has given promising results, synaptic dysfunction-modulating agents might be considered potential candidates for alleviating this disorder. Pinoresinol, a lignan found in Forsythia suspensa, is a memory-enhancing agent with excitatory synaptic activation. In the present study, we tested whether pinoresinol reduces learning and memory and excitatory synaptic deficits in an amyloid β (Aβ)-induced AD-like mouse model. Pinoresinol enhanced hippocampal long-term potentiation (LTP) through calcium-permeable AMPA receptor, which was mediated by Akt activation. Moreover, pinoresinol ameliorated LTP deficits in amyloid β (Aβ)-treated hippocampal slices via Akt signaling. Oral administration of pinoresinol ameliorated Aβ-induced memory deficits without sensory dysfunction. Moreover, AD-like pathology, including neuroinflammation and synaptic deficit, were ameliorated by pinoresinol administration. Collectively, pinoresinol may be a good candidate for AD therapy by modulating synaptic functions.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Disease Models, Animal; Furans; Hippocampus; Lignans; Long-Term Potentiation; Male; Memory Disorders; Mice, Inbred Strains; Neuronal Plasticity; Peptide Fragments; Proto-Oncogene Proteins c-akt; Receptors, AMPA

Neuroinflammation and loss of neurotrophic support have key roles in the pathophysiology of diabetes-associated behavioral deficits (DABD). Sesamin (Ses), a major lignan of sesame seed and its oil, shows anti-hyperglycemic, anti-oxidative, and neuroprotective effects. The present study was designed to assess the potential protective effects of Ses against DABD and investigate the roles of inflammatory markers and neurotrophic factors in streptozotocin (STZ)-induced diabetic rats. After confirmation of diabetes, Ses (30 mg/kg/day; P.O.) or insulin (6 IU/rat/day; S.C.) was administered to rats for eight consecutive weeks. During the eighth-week period of the study, behavioral functions of the animals were evaluated by employing standard behavioral paradigms. Moreover, inflammation status, neurotrophic factors, and histological changes were assessed in the cerebral cortex and hippocampal regions of the rats. The results of behavioral tests showed that STZ-induced diabetes increased anxiety-/depression-like behaviors, decreased locomotor/exploratory activities, and impaired passive avoidance learning and memory. These DABD were accompanied by neuroinflammation, lack of neurotrophic support, and neuronal loss in both cerebral cortex and hippocampus of the rats. Intriguingly, chronic treatment with Ses improved all the above-mentioned diabetes-related behavioral, biochemical, and histological deficits, and in some cases, it was even more effective than insulin therapy. In conclusion, the results suggest that Ses was capable of improving DABD, which might be ascribed, at least partly, to the reduction of blood glucose level, inhibition of neuroinflammation, and potentiation of neurotrophic factors.

Topics: Animals; Antioxidants; Anxiety; Cerebral Cortex; Depression; Diabetes Mellitus, Experimental; Dioxoles; Disease Models, Animal; Hippocampus; Inflammation; Lignans; Male; Maze Learning; Memory Disorders; Nerve Growth Factors; Neuroprotective Agents; Rats

Depression is a mood disorder that is related to neuroinflammation and cognition loss. This study is aimed to determine the potential antidepressant effects of (+)-sesamin, a lignan component of sesame, in a mild stress-induced depression mouse model. CD-1 mice were treated with chronic unpredictable mild stress (CUMS) process and orally administrated with sesamin (50 mg/kg/d) for 6 weeks. Behavioral tests including forced swimming test, tail suspension test, open field test, and elevated plus maze test demonstrated that sesamin treatment inhibited CUMS-induced mice depressant-like behaviors and anxiety, without changing immobility. It was found that sesamin prevented stress-induced decease levels of 5-HT and NE in striatum and serum. Cognitive deficits were assessed using Y-maze and Morris water maze test. Sesamin treatment also prevented stressed-induced memory impairments and neuronal damages. Consistently, sesamin also enhanced synapse ultrastructure and improved expressions of PSD-95 in stressed mice hippocampus with improving neurotrophic factors expression including BDNF and NT3. Moreover, sesamin treatment significantly prevented CUMS-induced neuroinflammation by inhibiting over-activation of microglia and expressions of inflammatory mediators including iNOS, COX-2, TNF-α and IL-1β in stressed mice hippocampus and cortex. These results illustrated that sesamin markedly improved CUMS-induced depression and memory loss via inhibiting neuroinflammation, which indicate that as food component, sesamin might be also a novel potential therapeutic for depression.

Topics: Animals; Antidepressive Agents; Behavior, Animal; Brain; Cytokines; Depression; Dietary Supplements; Dioxoles; Disease Models, Animal; Inflammation; Lignans; Male; Maze Learning; Memory Disorders; Mice, Inbred Strains; Nerve Tissue Proteins; Norepinephrine; Serotonin

Dementia is a category of brain diseases that cause a decrease in cognitive functions. Alzheimer's disease (AD) is the most frequently mentioned neurodegenerative disease showing dementia. Although many useful drugs for dementia were developed, we still need better and safer drugs. Here, we tested pinoresinol, a lignan found in sesame seed and olive oil, whether it could be a candidate for this purpose. Pinoresinol (25 mg/kg, p.o.) ameliorated memory impairment in dementia model induced by cholinergic blockade in the passive avoidance test in a dose-dependent manner. Moreover, pinoresinol (50 μM) facilitated induction of hippocampal long-term potentiation, a cellular model of learning and memory. Pinoresinol blocked acetylcholinesterase (AchE), an acetylcholine-degrading enzyme, activity in a concentration-dependent manner. Moreover, pinoresinol (50 μM) facilitated calcium influx into neuro2a cell. These results suggest that pinoresinol improves memory impairment and facilitates hippocampal LTP induction and these results might be related to the effect of pinoresinol on AChE and calcium influx.

Topics: Acetylcholinesterase; Animals; Calcium; Cell Line; Cholinesterase Inhibitors; Cyclic AMP Response Element-Binding Protein; Dementia; Extracellular Signal-Regulated MAP Kinases; Furans; Hippocampus; Lignans; Long-Term Potentiation; Male; Memory Disorders; Mice, Inbred ICR; Neuronal Plasticity; Proto-Oncogene Proteins c-akt; Scopolamine

Vascular dementia (VaD) is caused by chronic decreases in brain blood flow and accounts for 15-20% of dementia cases worldwide. In contrast to Alzheimer's disease (AD), no effective drug treatments are currently available for VaD. Previous studies have suggested that oxidative stress and neuroinflammation in the brain play important roles in the pathogenesis of VaD. Honokiol (HKL) is a well-known bioactive and nutraceutical compound that can act as an antioxidant and anti-inflammatory molecule. HKL can protect against memory impairments in AD mouse models. In this study, we explored whether the application of HKL was also protective against the insult of chronic cerebral hypoperfusion (CCH) in rats. We found that HKL supplementation prevented the memory impairments in the inhibitory avoidance step-down and Morris water maze tasks in CCH rats. HKL also suppressed the levels of oxidative stress and inflammation in CCH rats. Moreover, HKL prevented dendritic spines abnormalities in CCH rats. We also found that HKL inhibited the activity of GSK-3β, which may be critical for the neuroprotective activity of HKL. Thus, our study demonstrated the protective role of HKL in VaD.

Topics: Animals; Biphenyl Compounds; Brain; Dementia, Vascular; Disease Models, Animal; Enzyme Activation; Glycogen Synthase Kinase 3 beta; Inflammation; Lignans; Maze Learning; Memory Disorders; Neuroprotective Agents; Oxidative Stress; Rats; Rats, Wistar

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Cerebral Cortex; Chromatography, Liquid; Cognitive Dysfunction; Cyclooctanes; Female; Hippocampus; Lignans; Male; Maze Learning; Memory Disorders; Mice, Inbred C57BL; Mice, Transgenic; Neurotransmitter Agents; Nootropic Agents; Polycyclic Compounds; Presenilin-1; Tandem Mass Spectrometry

Oxidative stress, which is caused by Amyloid-β deposition in brain, plays an important role in Alzheimer's disease. In this study, we found that lignans from

Topics: Amyloid beta-Protein Precursor; Animals; Apoptosis; Disease Models, Animal; Lignans; Male; Maze Learning; Memory Disorders; Neurons; Neuroprotective Agents; Plant Stems; Rats; Reactive Oxygen Species; Schisandra; Superoxide Dismutase

Topics: Animals; Cyclin D1; Cyclin-Dependent Kinase 4; Cyclin-Dependent Kinase Inhibitor p19; Cyclooctanes; Dioxoles; Drugs, Chinese Herbal; Galactose; Gene Expression; Hippocampus; Humans; Learning Disabilities; Lignans; Male; Memory; Memory Disorders; Mice; Mice, Inbred ICR; Retinoblastoma Protein; rho GTP-Binding Proteins; Schisandra; Tumor Suppressor Protein p53

This study investigated the effects of (-)-sesamin on memory deficits induced by chronic electric footshock (EF)-induced stress in mice. Mice were treated with (-)-sesamin (25 and 50mg/kg, p.o., daily for 21day) prior to chronic EF stress (0.6mA, 1s every 5s for 3min, daily for 21day). Transfer retention latencies in the elevated plus maze test and N-methyl-d-aspartate (NMDA) receptor (type 1) phosphorylation in the hippocampus increased with chronic EF stress, and they were reduced by treatment with (-)-sesamin at both doses. Phosphorylation of extracellular signal-regulated kinase (ERK1/2) and cyclic AMP-responsive element binding protein (CREB), which were reduced by chronic EF stress, were increased by treatment with (-)-sesamin. Retention latencies in the passive avoidance test and dopamine levels in the substantia nigra-striatum were also reduced by chronic EF stress, and similarly recovered with (-)-sesamin treatment. These results suggest that (-)-sesamin ameliorates the effects of chronic EF stress-induced spatial and habit learning memory deficits by modulating both NMDA receptor and dopaminergic neuronal systems.

Topics: Animals; Avoidance Learning; Corpus Striatum; Cyclic AMP Response Element-Binding Protein; Dioxoles; Dopamine; Electroshock; Hippocampus; Lignans; Male; Maze Learning; Memory Disorders; Mice, Inbred ICR; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Phosphorylation; Reaction Time; Receptors, N-Methyl-D-Aspartate; Spatial Memory; Stereoisomerism; Stress, Physiological

The present study investigated the effects of (-)-sesamin on motor and memory deficits in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned mouse model of Parkinson's disease (PD) with l-3,4-dihydroxyphenylalanine (l-DOPA). MPTP-lesioned (30mg/kg/day, 5days) mice showed deficits in memory including habit learning memory and spatial memory, which were further aggravated by daily treatment with 25mg/kg l-DOPA for 21days. However, daily treatment with (-)-sesamin (25 and 50mg/kg) for 21days ameliorated memory deficits in an MPTP-lesioned mouse model of PD treated with l-DOPA (25mg/kg). Both (-)-sesamin doses reduced decreases in the retention latency time in the passive avoidance test, latency to fall of rotarod test and distance traveled in the open field test, and attenuated decreases in tyrosine hydroxylase (TH)-immunopositive cells, dopamine, and its metabolites in the substantia nigra-striatum. (-)-Sesamin reduced increases in the retention transfer latency time in the elevated plus-maze test and N-methyl-d-aspartate receptor (NMDAR) expression and reduced decreases in the phosphorylation of extracellular signal-regulated kinase (ERK1/2) and cyclic AMP-response element binding protein (CREB) in the hippocampus. In contrast, daily treatment with 10mg/kg l-DOPA for 21days ameliorated memory deficits in MPTP-lesioned mice, and this effect was further improved by treatment with (-)-sesamin (25 and 50mg/kg). These results suggest that (-)-sesamin protects against habit learning memory deficits by activating the dopamine neuronal system, while spatial memory deficits are decreased by its modulatory effects on the NMDAR-ERK1/2-CREB system. Accordingly, (-)-sesamin may act as an adjuvant phytonutrient for motor and memory deficits in patients with PD receiving l-DOPA.

Topics: Animals; Antiparkinson Agents; Avoidance Learning; Corpus Striatum; Dioxoles; Dopamine; Dose-Response Relationship, Drug; Levodopa; Lignans; Male; Memory; Memory Disorders; Mice, Inbred C57BL; Motor Activity; Nootropic Agents; Parkinsonian Disorders; RNA, Messenger; Substantia Nigra

Schizandrin (SCH) has been reported to prevent or reduce learning and memory defects. However, it is not known whether SCH ameliorates cognitive impairments induced by oestrogen deficiency. In the present study, we investigated the effect of SCH on memory in ovariectomized (OVX) and non-OVX rats.. A passive avoidance test was used to evaluate the effect of SCH on memory. Field EPSPs were recorded in hippocampal slices using an electrophysiological method. In OVX rats, biochemical parameters in the bilateral hippocampus were measured; these included superoxide dismutase (SOD), malondialdehyde (MDA) and AChE. Also, the number of NADPH-diaphorase (NADPH-d) positive neurons was counted by NADPH-d histochemistry staining technique.. Oral SCH improved the memory and facilitated the induction of long-term potentiation in non-OVX and OVX rats; this effect was more obvious in OVX rats. Similarly, SCH perfusion enhanced synaptic transmission in hippocampal slices from both non-OVX and OVX rats. However, SCH perfusion reduced the ratio of paired-pulse facilitation only in OVX but not in non-OVX rats. In addition, SCH decreased AChE activity and MDA level and increased SOD activity and the number of NADPH-d-positive neurons in OVX rats.. SCH improves memory in OVX rats and its potential mechanisms may include a reduction in the loss of hippocampal NADPH-d positive neurons, an increase of antioxidant properties and a potentiation of synaptic transmission that possibly involves to enhance cholinergic function. Overall, our findings indicate that SCH has potential as a therapeutic strategy for the cognitive dysfunctions associated with the menopause.

Topics: Acetylcholinesterase; Animals; Antioxidants; Avoidance Learning; Cell Count; Cyclooctanes; Excitatory Postsynaptic Potentials; Female; GPI-Linked Proteins; Hippocampus; Lignans; Long-Term Potentiation; Malondialdehyde; Memory Disorders; Ovariectomy; Polycyclic Compounds; Rats; Superoxide Dismutase; Synaptic Transmission

Honokiol, a lignan isolated from the bark of Magnolia officinalis, has been reported to ameliorate the learning and memory impairments in senesed (SAMP8) mice. However, whether honokiol could improve scopolamine (SCOP)-induced learning and memory deficits in mice is still unknown. In this study, we aimed to investigate whether honokiol could reverse the SCOP-induced learning and memory impairments in mice and to elucidate its underlying mechanisms of action. Mice were given daily intraperitoneal injection of honokiol (10 and 20mg/kg) for 21 consecutive days. The results showed that honokiol significantly improved spatial learning and memory function (as assessed by the Morris water maze test) in the SCOP-treated mice. In addition, treatment with honokiol significantly decreased the protein and mRNA levels of interleukin (IL)-1β and the activity of acetylcholinesterase (AChE), while significantly increased the protein and mRNA levels of IL-10, and the level of acetylcholine (Ach) in the brain of the SCOP-treated mice. Moreover, honokiol also significantly suppressed the production of prostaglandin E 2 (PGE2) and mRNA expression of cyclooxygenase-2 (COX-2) in the brain of the SCOP-treated mice. Mechanistic investigations revealed that honokiol could markedly reverse the amount of phosphorylated Akt and extracellular regulated kinases 1/2 (ERK1/2) changes in the brain of the SCOP-treated mice. These results amply demonstrated that honokiol could improve learning and memory impairments induced by SCOP in mice, and the protective action may be mediated, at least in part, by inhibition of AChE activity, and amelioration of the neuroinflammatory processes in the SCOP-treated mice.

Topics: Animals; Biphenyl Compounds; Brain; Cholinesterase Inhibitors; Drugs, Chinese Herbal; Lignans; Male; Maze Learning; Memory Disorders; Mice; Mice, Inbred ICR; Scopolamine

Alzheimer's disease (AD), one of the most common forms of dementia, is primarily ascribed to the cholinergic deficits and neuronal dysfunction. Magnolol (Mag), a bioactivator extracted from Magnolia officinalis, has protective effects on cholinergic neurons, but the specific mechanism remains unknown. To further evaluate the therapeutic effects of Mag on the learning and memory impairment in a scopolamine (Scop)-induced mouse model, the passive avoidance and the Morris water maze tests, the measurement of the ratio of brain/hippocampus to body weight, activities of acetyl cholinesterase (AChE), superoxide dismutase (SOD), total nitric oxide synthase (total NOS) and the content of methane dicarboxylic aldehyde (MDA) in hippocampus homogenate as well as the immunefluorescence staining of the AChE positive nerve fibers were performed. Therapeutically treated with Mag, the impaired abilities of learning and memory of the Scop-induced mice were almost restored to the native levels. The restored AChE, total NOS and SOD activities and the MDA level were observed, with a relatively normal density of AChE positive nerve fibers in hippocampus CA3 molecular layer. The improving efficacy of Mag on learning and memory impairment induced by Scop is dose-dependent, indicating that Mag has potential neuroprotective effects against neuronal impairment and memory dysfunction induced by Scop in mice. The underlying mechanisms may be associated with the anti-oxidative effects of Mag and its protective effects on hippocampus cholinergic neurons.

Topics: Acetylcholine; Animals; Avoidance Learning; Biphenyl Compounds; Brain; Cholinergic Neurons; Lignans; Male; Malondialdehyde; Maze Learning; Memory Disorders; Mice; Nerve Fibers; Neuroprotective Agents; Nitric Oxide Synthase; Organ Size; Scopolamine; Superoxide Dismutase

Alzheimer's disease (AD) chiefly characterizes a progressively neurodegenerative disorder of the brain, and eventually leads to irreversible loss of intellectual abilities. The β-amyloid (Aβ)-induced neurodegeneration is believed to be the main pathological mechanism of AD, and Aβ production inhibition or its clearance promotion is one of the promising therapeutic strategies for anti-AD research. Here, we report that the natural product arctigenin from Arctium lappa (L.) can both inhibit Aβ production by suppressing β-site amyloid precursor protein cleavage enzyme 1 expression and promote Aβ clearance by enhancing autophagy through AKT/mTOR signaling inhibition and AMPK/Raptor pathway activation as investigated in cells and APP/PS1 transgenic AD model mice. Moreover, the results showing that treatment of arctigenin in mice highly decreased Aβ formation and senile plaques and efficiently ameliorated AD mouse memory impairment strongly highlight the potential of arctigenin in anti-AD drug discovery.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Brain; Cells, Cultured; Disease Models, Animal; eIF-2 Kinase; Embryo, Mammalian; Eukaryotic Initiation Factor-2; Furans; Gene Expression Regulation; Humans; Lignans; Maze Learning; Memory Disorders; Mice; Mice, Transgenic; Mutation; Neurons; Presenilin-1; Signal Transduction; TOR Serine-Threonine Kinases

The fruits of Schisandra chinensis (Trucz.) Baill. (Schisandraceae) which have been used as a tonic especially for kidney yin deficiency in Chinese traditional medicine are recently receiving attention for its preventive activity on age-related neurodegenerative diseases. A variety of studies demonstrated the cognitive-enhancing effects of Schisandra chinensis through animal tests and also in clinical trials.. In this study, we attempted to investigate the effects of the lignan-riched extract of Schisandra chinensis fruits (ESP-806) on neurotoxicity and memory impairment induced by Aβ1-42 injection in mice.. The fruits of Schisandra chinensis were extracted with the mixture of n-hexane:ethanol (9:1), which is riched with bioactive dibenzocyclooctadiene lignans, schizandrin, gomisin N, wuweigisu C. After oral treatment of ESP-806 (100 mg/kg body weight) followed by injection of Aβ1-42 (2 μg/mouse, i.c.v.), novel object recognition and passive avoidance tests were evaluated. To verify the cognition enhancing effects of ESP-806, we examined the effects of ESP-806 on the activities of β-secretase and acetylcholinesterase, and the contents of Aβ and the reduced glutathione within the cortex and hippocampus of Aβ-injected mice.. Oral treatment of ESP-806 (100 mg/kg body weight) significantly attenuated Aβ1-42-induced memory impairment evaluated by behavioral tests. Furthermore, the treatment of ESP-806 attenuated the elevation of β-secretase activity accompanying the reduced level of Aβ1-42 in the cortex and hippocampus of the brain. ESP-806 also significantly inhibited the acetylcholinesterase activity in the hippocampus and increased the content of the reduced glutathione in the cortex and hippocampus of mouse brain.. These data suggested that the extract of Schisandra chinensis fruits riched with dibenzocyclooctadiene lignans may be useful in the prevention and treatment of Alzheimer's disease.

Topics: Acetylcholinesterase; Amyloid beta-Peptides; Amyloid Precursor Protein Secretases; Animals; Avoidance Learning; Cerebral Cortex; Cognition Disorders; Fruit; Glutathione; Hippocampus; Lignans; Male; Memory Disorders; Mice; Mice, Inbred ICR; Neuroprotective Agents; Peptide Fragments; Phytotherapy; Plant Extracts; Recognition, Psychology; Schisandra

Alzheimer's disease (AD), the most common form of dementia, is characterized by memory deficits and deposition of amyloid-β (Aβ) in the brain. It has been known that neuroinflammation and oxidative stress are critical factors in the development of AD. 4-O-methylhonokiol, an extract from Magnolia officinalis, is known to have anti-inflammatory and anti-oxidative effects. Thus, we investigated the properties of 4-O-methylhonokiol against progression and development of AD in Tg2576 mice. Tg2576 mice models show memory impairment and AD-like pathological features including Aβ deposition. Oral administration of 4-O-methylhonokiol through drinking water (1 mg/kg in 0.0002% Tween 80) for 12 weeks not only prevented memory impairment but also inhibited Aβ deposition. In addition, 4-O-methylhonokiol decreased β-secretase activity, oxidative lipid and protein damage levels, activation of astrocytes and microglia cells, and generation of IL-1β and TNF-α with increase of glutathione level in the brain. Our results showed that 4-O-methylhonokiol effectively prevented memory impairment by down-regulating β-secretase activity through inhibition of oxidative stress and neuroinflammatory responses in Tg2576 transgenic mice.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Amyloid Precursor Protein Secretases; Analysis of Variance; Animals; Anti-Inflammatory Agents; Avoidance Learning; Biphenyl Compounds; Brain; Disease Models, Animal; Exploratory Behavior; Gene Expression Regulation; Glutathione; Humans; Lignans; Lipid Peroxidation; Maze Learning; Memory Disorders; Mice; Mice, Transgenic; Mutation; Oxidative Stress; Peptide Fragments; Protein Carbonylation; Time Factors

Neuroinflammation is important in the pathogenesis and progression of Alzheimer disease (AD). Previously, we demonstrated that lipopolysaccharide (LPS)-induced neuroinflammation caused memory impairments. In the present study, we investigated the possible preventive effects of 4-O-methylhonokiol, a constituent of Magnolia officinalis, on memory deficiency caused by LPS, along with the underlying mechanisms.. We investigated whether 4-O-methylhonokiol (0.5 and 1 mg/kg in 0.05% ethanol) prevents memory dysfunction and amyloidogenesis on AD model mice by intraperitoneal LPS (250 μg/kg daily 7 times) injection. In addition, LPS-treated cultured astrocytes and microglial BV-2 cells were investigated for anti-neuroinflammatory and anti-amyloidogenic effect of 4-O-methylhonkiol (0.5, 1 and 2 μM).. Oral administration of 4-O-methylhonokiol ameliorated LPS-induced memory impairment in a dose-dependent manner. In addition, 4-O-methylhonokiol prevented the LPS-induced expression of inflammatory proteins; inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) as well as activation of astrocytes (expression of glial fibrillary acidic protein; GFAP) in the brain. In in vitro study, we also found that 4-O-methylhonokiol suppressed the expression of iNOS and COX-2 as well as the production of reactive oxygen species, nitric oxide, prostaglandin E2, tumor necrosis factor-α, and interleukin-1β in the LPS-stimulated cultured astrocytes. 4-O-methylhonokiol also inhibited transcriptional and DNA binding activity of NF-κB via inhibition of IκB degradation as well as p50 and p65 translocation into nucleus of the brain and cultured astrocytes. Consistent with the inhibitory effect on neuroinflammation, 4-O-methylhonokiol inhibited LPS-induced Aβ1-42 generation, β- and γ-secretase activities, and expression of amyloid precursor protein (APP), BACE1 and C99 as well as activation of astrocytes and neuronal cell death in the brain, in cultured astrocytes and in microglial BV-2 cells.. These results suggest that 4-O-methylhonokiol inhibits LPS-induced amyloidogenesis via anti-inflammatory mechanisms. Thus, 4-O-methylhonokiol can be a useful agent against neuroinflammation-associated development or the progression of AD.

Topics: Amyloid beta-Peptides; Amyloid Precursor Protein Secretases; Analysis of Variance; Animals; Anti-Inflammatory Agents; Aspartic Acid Endopeptidases; Astrocytes; Avoidance Learning; Biphenyl Compounds; Brain; Cell Line, Transformed; Cyclooxygenase 2; Cytokines; Dinoprostone; Disease Models, Animal; Electrophoretic Mobility Shift Assay; Glial Fibrillary Acidic Protein; In Situ Nick-End Labeling; Inflammation; Lignans; Lipopolysaccharides; Male; Maze Learning; Memory Disorders; Mice; Mice, Inbred ICR; Microglia; NF-kappa B; Nitric Oxide; Peptide Fragments

In the present study, we examined the effects of deoxyschisandrin (DS) from Schisandra chinensis on the amyloid-beta₁₋₄₂ (Aβ₁₋₄₂)-induced memory impairment in mice and investigated the possible antioxidative mechanism. Mice were given an intracerebroventricular (i. c. v.) injection with the aggregated Aβ₁₋₄₂ and then treated with DS (4, 12, and 36 mg/kg body weight) or donepezil (DPZ), a positive control drug (0.65 mg/kg), by intragastric infusion for 14 days. Non-cognitive disturbances and cognitive performance were evaluated by the locomotor activity, Y-maze, and water maze tests. Antioxidative enzyme activities including superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) and levels of malondialdehyde (MDA), glutathione (GSH), and oxidized glutathione (GSSG) within the cerebral cortex and hippocampus of mice were measured to investigate the mechanism. Our results showed that DS significantly improved Aβ₁₋₄₂-induced short-term and spatial memory impairments in the Y-maze and water maze tests. Furthermore, in the cerebral cortex and hippocampus of mice, the reduced activities of SOD and GSH-px, the GSH level, and the GSH/GSSG ratio were increased, and increased levels of MDA and GSSG were reduced following treatment with DS, although the improvement of GSH and the reduction of GSSG levels were not marked. These results suggest that DS is a potential cognitive enhancer in Alzheimer's disease through its antioxidative action.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Antioxidants; Cerebral Cortex; Cyclooctanes; Drugs, Chinese Herbal; Fruit; Glutathione; Glutathione Peroxidase; Hippocampus; Lignans; Male; Malondialdehyde; Maze Learning; Memory Disorders; Mice; Polycyclic Compounds; Schisandra; Superoxide Dismutase

In the present study, we examined the effect of schisandrin (SCH) of Schisandra chinensis on the amyloid-beta(1-42)- (Aβ(1-42)-) induced memory impairment in mice and elucidated the possible antioxidative mechanism. Mice were intracerebroventricular (i.c.v.) injected with the aggregated Aβ(1-42) and then treated with SCH (4, 12, and 36 mg/kg body weight) or donepezil (DPZ), a reference drug (0.65 mg/kg) by intragastric infusion for 14 days. Noncognitive disturbances and cognitive performance were evaluated by locomotor activity test, Y-maze test, and water maze test. Antioxidative enzyme activities including superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) and levels of malondialdehyde (MDA), glutathione (GSH), and oxidized glutathione (GSSG) within the cerebral cortex and hippocampus of mice were measured to elucidate the mechanism. Our results showed that SCH significantly improved Aβ(1-42)-induced short-term and spatial reference memory impairments in Y-maze test and water maze test. Furthermore, in the cerebral cortex and hippocampus of mice, SOD and GSH-px activities, GSH level, and GSH/GSSG ratio were increased, and levels of MDA and GSSG were decreased by the treatment of SCH. These results suggest that SCH is a potential cognitive enhancer against Alzheimer's disease through antioxidative action.

Topics: Amyloid beta-Peptides; Animals; Antioxidants; Biological Assay; Cerebral Cortex; Cyclooctanes; Hippocampus; Lignans; Male; Maze Learning; Memory Disorders; Mice; Motor Activity; Peptide Fragments; Polycyclic Compounds; Reaction Time; Schisandra

Oxidative stress induced neuronal cell death by accumulation of β-amyloid (Aβ) is a critical pathological mechanism of Alzheimer's disease (AD). Intracerebroventrical infusion of Aβ(1-42) (300 pmol/day per mouse) for 14 days induced neuronal cell death and memory impairment, but pre-treatment of 4-O-methylhonokiol (4-O-MH), a novel compound extracted from Magnolia officinalis for 3 weeks (0.2, 0.5 and 1.0 mg/kg) prior to the infusion of Aβ(1-42) and during the infusion dose dependently improved Aβ(1-42)-induced memory impairment and prevented neuronal cell death. Additionally, 4-O-MH reduced Aβ(1-42) infusion-induced oxidative damages of protein and lipid but reduced glutathione levels in the cortex and hippocampus. Aβ(1-42) infusion-induced activation of astrocytes and p38 mitogenic activated protein (MAP) kinase was also prevented by 4-O-MH in mice brains. In further study using culture cortical neurons, p38 MAP kinase inhibitor abolished the inhibitory effect of 4-O-MH (10 μM) on the Aβ(1-42) (5 μM)-induced reactive oxidative species generation and neuronal cell death. These results suggest that 4-O-MH might prevent the development and progression of AD through the reduction of oxidative stress and neuronal cell death via inactivation of p38 MAP kinase pathway.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Analysis of Variance; Animals; Apoptosis; Astrocytes; Biphenyl Compounds; Cell Survival; Cells, Cultured; Disease Models, Animal; Hippocampus; Lignans; Lipid Peroxidation; Magnolia; Male; Memory Disorders; Mice; Mice, Inbred ICR; Neurons; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Peptide Fragments; Protein Carbonylation; Reactive Oxygen Species

Presenilin 2 (PS2) mutation increases Aβ generation and neuronal cell death in the brains of Alzheimer disease (AD) patients. In a previous study, we showed that increased oxidative damage and activation of extracellular signal-regulated kinase (ERK) were associated with Aβ generation and neuronal cell death in neuronal cells expressing mutant PS2. In this study, we show that oral treatment with 4-O-methylhonokiol, a novel compound isolated from Magnolia officinalis, for 3 months (1.0mg/kg) prevented PS2 mutation-induced memory impairment and neuronal cell death accompanied by a reduction in Aβ(1-42) accumulation. We also found that 4-O-methylhonokiol inhibited PS2 mutation-induced activation of ERK and β-secretase, and oxidative protein and lipid damage, but recovered glutathione levels in the cortex and hippocampus of PS2 mutant mice. Additionally, 4-O-methylhonokiol prevented PS2 mutation-induced activation of astrocytes as well as production of TNF-α, IL-1β, reactive oxygen species (ROS), and nitric oxide (NO) in neurons. Generation of TNF-α, IL-1β, ROS, and NO and ERK activation in cultured astrocytes treated with lipopolysaccharide (1μg/ml) were also prevented by 4-O-methylhonokiol in a dose-dependent manner. These results suggest that the improving effects of 4-O-methylhonokiol on memory function may be associated with a suppression of the activation of ERK and astrocytes as well as a reduction in oxidative damage. Thus, 4-O-methylhonokiol may be useful in the prevention and treatment of AD.

Topics: Animals; Anti-Inflammatory Agents; Apoptosis; Astrocytes; Biphenyl Compounds; Down-Regulation; Drug Evaluation, Preclinical; Extracellular Signal-Regulated MAP Kinases; Lignans; MAP Kinase Signaling System; Memory Disorders; Mice; Mice, Mutant Strains; Mice, Transgenic; Models, Biological; Oxidative Stress; Presenilin-2

The seeds of Arctium lappa L. (AL, family Asteraceae), the main constituents of which are arctiin and arctigenin, have been used as an herbal medicine or functional food to treat inflammatory diseases. These main constituents were shown to inhibit acetylcholinesterase (AChE) activity. Arctigenin more potently inhibited AChE activity than arctiin. Arctigenin at doses of 30 and 60 mg/kg (p. o.) potently reversed scopolamine-induced memory deficits by 62 % and 73 %, respectively, in a passive avoidance test. This finding is comparable with that of tacrine (10 mg/kg p. o.). Arctigenin also significantly reversed scopolamine-induced memory deficits in the Y-maze and Morris water maze tests. On the basis of these findings, arctigenin may ameliorate memory deficits by inhibiting AChE.

Topics: Acetylcholinesterase; Animals; Arctium; Avoidance Learning; Cholinesterase Inhibitors; Drugs, Chinese Herbal; Functional Food; Furans; Glucosides; Lignans; Male; Maze Learning; Memory Disorders; Mice; Mice, Inbred ICR; Phytotherapy; Plant Extracts; Scopolamine; Seeds; Tacrine

The preventive effect of schisandrin B (Sch B), an antioxidant ingredient of Schisandra chinensis, was studied on scopolamine-induced dementia in mouse. Scopolamine developed oxidative stress in the brain with the decreased levels of antioxidant enzymes and increased nitrite level. At the same time, a significant impairment of learning and memory occurred when evaluated by passive avoidance task (PAT) and Morris water maze (MWM) with concomitant increase of acetylcholinesterase (AChE) activity and decreased acetylcholine levels. Pre-treatment by Sch B (10, 25, 50 mg/kg) effectively prevented scopolamine-induced oxidative stress and improved behavioural tasks. Further, the scopolamine-induced increase in AChE activity was significantly suppressed and the level of acetylcholine was maintained as normal by Sch B treatment. These results suggest that Sch B have protective function against cerebral functional defects such as dementia not only by antioxidant prevention but also exerting its potent cognitive-enhancing activity through modulation of acetylcholine level.

Topics: Acetylcholinesterase; Animals; Antioxidants; Cyclooctanes; Lignans; Male; Maze Learning; Memory Disorders; Mice; Mice, Inbred BALB C; Oxidative Stress; Polycyclic Compounds; Schisandra; Scopolamine

Accumulations of amyloid-β (Aβ) and oxidative damage are critical pathological mechanisms in the development of Alzheimer's disease (AD). We previously found that 4-O-methylhonokiol, a compound extracted from Magnolia officinalis, improved memory dysfunction in Aβ-injected and presenilin 2 mutant mice through the reduction of accumulated Aβ. To investigate mechanisms of the reduced Aβ accumulation, we examined generation, degradation, efflux and aggregation of Aβ in Swedish AβPP AD model (AβPPsw) mice pre-treated with 4-O-methylhonokiol (1.0 mg/kg) for 3 months. 4-O-methylhonokiol treatment recovered memory impairment and prevented neuronal cell death. This memory improving activity was associated with 4-O-methylhonokiol-induced reduction of Aβ1-42 accumulation in the brains of AβPPsw mice. According to the reduction of Aβ1-42 accumulation, 4-O-methylhonkiol modulated oxidative damage sensitive enzymes. 4-O-methylhonkiol decreased expression and activity of brain beta-site AβPP cleaving enzyme (BACE1), but increased clearance of Aβ in the brain through an increase of expressions and activities of Aβ degradation enzymes; insulin degrading enzyme and neprilysin. 4-O-methylhonkiol also increased expression of Aβ transport molecule, low density lipoprotein receptor-related protein-1 in the brain and liver. 4-O-methylhonkiol decreased carbonyl protein and lipid peroxidation, but increased glutathione levels in the brains of AβPPsw mice suggesting that oxidative damage of protein and lipid is critical in the impairment of those enzyme activities. 4-O-methylhonokiol treatment also prevented neuronal cell death in the AβPPsw mousee brain through inactivation of caspase-3 and BAX. These results suggest that 4-O-methylhonokiol might prevent the development and progression of AD by reducing Aβ accumulation through an increase of clearance and decrease of Aβ generation via antioxidant mechanisms.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Amyloid Precursor Protein Secretases; Analysis of Variance; Animals; Avoidance Learning; Biphenyl Compounds; Brain; Circular Dichroism; Disease Models, Animal; Exploratory Behavior; Humans; Lignans; Lipid Peroxidation; Maze Learning; Memory Disorders; Mice; Mice, Transgenic; Neprilysin; Presenilin-2; Protein Carbonylation; Reaction Time

To observe the effects of schizandrins on the learning and memory disorder in mice, and explore its mechanism.. The memory impairment model was established by using the pentobarbital sodium (20 mg x kg(-1)) intraperitoneally injected in mice. Schizandrins (0.5, 1.0, 2.0 g x kg(-1)) were administered through intragavage for consecutive 14 days. Morris Water Maze test was used to evaluate the impairment of learning and memory. The energy of superoxide dismutase (SOD), nitric oxide (NO) and catalase (CAT) of brain tissue were measured. And the positive expression of nuclear transcription factor-kappaB p65 (NF-kappaB p65), caspase-3 in the hippocampus CA1 region were determined by immunohistochemical analysis. At the cellular level, 24 h after schizandrins (0.062 5, 0.125, 0.25 g x L(-1)) were pre-administered, the apoptosis model of PC12 cell was induced by H2O2, and activity of PC12 cell was detected by MTT colorimetric assay, the energy of NO in cell serum were measured. The expression of Bcl-2 was determined by the combination of immunocytochemical staining and image analysis software.. Morris Water Maze test showed that the model group mice took shorter searching time and distance on the previous flat area than those in the control group (P < 0.05), which could be prolonged after schizandrins treatment (P < 0.05, P < 0.01). Compared with the control group, the level of NO increased while the activity of SOD, CAT decreased in the model group (both P < 0.01). After treated with schizandrins, the level of NO significantly decreased (P < 0.01), while the activity of SOD increased (P < 0.01). Immunohistochemistry analysis showed that the protein expression of NF-kappaB p65, Caspase-3 in the hippocampal CA1 region significantly increased after modeling, while schizandrins (1.0 g x kg(-1)) can significantly inhibit the protein expression of NF-kappaB p65, Caspase-3 (P < 0.05, P < 0.01). Compared with the H2O2, model group, schizandrins (0.125, 0.25 g x L(-1)) can significantly increased PC12 cell activity and decreased the NO level (P < 0.05, P < 0.01), the expression of Bcl-2 in the schizandrins group (0.125, 0.25 g x L(-1)) was up-regulated.. Schizandrins could improve the learning-memory dysfunction induced by the sodium pentobarbital in mice, and its protective mechanism is related to the lowering oxidative damage and inhibiting the cell apoptosis through up-regulating the expression of Bcl-2.

Topics: Animals; Apoptosis; Behavior, Animal; CA1 Region, Hippocampal; Caspase 3; Cell Line; Cyclooctanes; Disease Models, Animal; Drugs, Chinese Herbal; Female; Learning Disabilities; Lignans; Male; Memory Disorders; Mice; Nitric Oxide; Oxidative Stress; PC12 Cells; Polycyclic Compounds; Proto-Oncogene Proteins c-bcl-2; Rats; Superoxide Dismutase; Transcription Factor RelA

The present study investigated the effect of schizandrin, a component of the fruit of Schizandra chinesis Baill (Fructus Schizandrae), on memory impairment in rats. Scopolamine (0.5 mg/kg, i.p.), a non-selective muscarinic receptor antagonist, markedly impaired spatial memory in an eight-arm radial maze. A higher dose of scopolamine (3 mg/kg, i.p.) also impaired the passive avoidance response. Schizandrin (1 and 10 mg/kg, p.o.) significantly reversed the scopolamine-induced impairment of spatial memory. Similarly, schizandrin (1 mg/kg, p.o.) significantly reversed the scopolamine-induced impairment of the passive avoidance response. Moreover, in mice, schizandrin (1 and 10 mg/kg, p.o.) enhanced tremors induced by oxotremorine, a muscarinic M(1) receptor agonist. Taken together these findings suggest that schizandrin reverses scopolamine-induced memory impairment, in part, by enhancing cholinergic function, and that schizandrin might be useful for treating memory deficits.

Topics: Animals; Avoidance Learning; Cyclooctanes; Dose-Response Relationship, Drug; Lignans; Male; Maze Learning; Memory Disorders; Molecular Structure; Muscarinic Antagonists; Oxotremorine; Phytotherapy; Polycyclic Compounds; Rats; Rats, Wistar; Schisandra; Scopolamine

This study is to investigate the protective effect of (-) clausenamide against the neurotoxicity of okadaic acid in SH-SY5Y cell line, and injection beta-amyloid peptide25-35 (Abeta25-35) to the cerebral ventricle in ovariectomy (OVX) rats. MTT assay, LDH assay, and Hoechst 33258 staining were used to detect the effect of (-) clausenamide on the toxicity of okadaic acid in SH-SY5Y cell line. The animal model was induced by ovariectomized and injection of Abeta25-35 in the cerebroventricle of rats. The effect of (-) clausenamide on learning and memory deficiency was observed by step-through test. Electron microscope, Nissl body staining, and HE staining were used to examine the morphological changes in hippocampus and cerebral cortex neurons. Pretreatment of (-) clausenamide and LiCl decreased the rate of cell death from MTT, LDH release, and apoptosis from Hoechst 33258 staining in SH-SY5Y cell line. The step-through tests showed (-) clausenamide could improve the ability of learning and memory. The Nissl body staining and HE staining experiments also showed the neuroprotective effects of (-) clausenamide on the neurons of hippocampus and cerebral cortex. (-) Clausenamide has the protective effects against the neurotoxicity induced by okadaic acid and Abeta25-35.

Topics: Amyloid beta-Peptides; Animals; Apoptosis; Cell Line, Tumor; Cell Survival; Cerebral Cortex; Clausena; Drugs, Chinese Herbal; Female; Hippocampus; Humans; L-Lactate Dehydrogenase; Lactams; Learning; Lignans; Memory Disorders; Neuroblastoma; Neurons; Neuroprotective Agents; Okadaic Acid; Ovariectomy; Peptide Fragments; Plants, Medicinal; Rats; Rats, Sprague-Dawley