Rosmarinic acid and ursolic acid alleviate deficits in cognition, synaptic regulation and adult hippocampal neurogenesis in an Aß1-42-induced mouse model of Alzheimer's disease.

BACKGROUND: Rosmarinus officinalis, commonly known as rosemary, is a medicinal herb that presents significant biological properties such as antimicrobial, antioxidant, anti-inflammatory, anti-diabetic and anti-depressant activities. Recent findings correlate impaired adult neurogenesis, which is crucial for the maintenance of synaptic plasticity and hippocampal functioning, synaptic regulation with the pathological hallmarks of Alzheimer's disease (AD). These observations call for the need to developing compounds that promote neurogenesis and alleviates deficits in cognition and synaptic regulation. PURPOSE AND STUDY DESIGN: The present study was conducted to determine the proneurogenic effects of R. officinalis and its active compounds (ursolic acid and rosmarinic acid) in comparison to Donepezil in an Aß1-42-induced mouse model of AD. METHODS: BALB/c mice were divided into ten groups. Half were injected with Aß1-42 in the hippocampus through stereotaxic surgery to generate the disease groups. The other half received control injections. Each set of five groups were administered orally with vehicle, an ethanolic extract of R. officinalis, ursolic acid, rosmarinic acid or donepezil. Behavior analysis included the Morris water maze test, the novel object recognition test and the Elevated plus maze. The mice were then sacrificed and the hippocampal tissue was processed for immunohistochemistry and gene expression analysis. RESULTS: The results show a protective effect by rosmarinic acid and ursolic acid in reversing the deficits in spatial and recognition memory as well as changes in anxiety induced by Aß1-42. The neuronal density and the expression levels of neurogenic (Ki67, NeuN and DCX) and synaptic (Syn I, II, III, Synaptophysin and PSD-95) markers were also normalized upon treatment with rosmarinic and ursolic acid. CONCLUSION: Our findings indicate the potential of R. officinalis and its active compounds as therapeutic agents against Aß1-42-induced neurotoxicity in AD.

Short-term supplementation of DHA as phospholipids rather than triglycerides improve cognitive deficits induced by maternal omega-3 PUFA deficiency during the late postnatal stage.

Cognitive deficiencies, which are caused by maternal omega-3 PUFA deficiency (O-3 Def), are likely to be more rapidly and easily reversed at younger ages with quicker DHA reversal. This study aims to compare the efficiency of short-term supplementation of DHA in the form of phospholipids (PL) and triglycerides (TG) and improve cognitive deficiency in the O-3 Def model during different periods of brain development (3-week and 7-week old). The animal's spatial task performance, brain PUFA concentration, histopathology, and expression of synapse-associated proteins in the hippocampus were then analyzed. We demonstrate here that DHA-PL shows improved efficiency in improving cognitive deficiency compared to DHA-TG, particularly for adult O-3 Def offspring. The superiority of DHA-PL also correlates with the specific elevation of synapse-associated proteins, including BDNF, DCX, GAP-43, Syn, and PSD95, except to higher brain DHA accretion. This work highlights the DHA-PL as a better DHA supplement for inferior brain development caused by maternal O-3 Def, especially regarding those who missed the optimal time window of neurodevelopment.

Behavioral and neurological improvement by Cydonia oblonga fruit extract in chronic immobilization stress rats.

It is known that chronic stress is a contributing factor to several physical and mental diseases. In this study, we examined the effect of hydroethanolic extract of Cydonia oblonga fruit (HECO, 300 mg/kg) in chronically immobilized rats on physiological and behavioral parameters by the open field test (OFT), sucrose preference test (SPT), and forced swimming test (FST) and on neurological alterations by analysis of the hippocampal neurogenesis. A daily 6 hr exposure to chronic immobilization stress (CIS) for 21 consecutive days induced anxiety- and depressive-like behaviors in rats' concomitant with decreased weight gain and increased plasma corticosterone (CORT) levels, rats also showed atrophy in the CA3 subregion of the hippocampus and a decreased number of Ki67 and DCX positive cells in the dentate gyrus (DG). Treatment with HECO successfully suppressed the physiological and behavioral markers of the CIS and prevents the structural abnormality and the impaired cell proliferation in the hippocampus. Moreover, the daily administration of HECO improved the mood function in normal rats. Taking together, our findings demonstrate, for the first time, the anti-depressive effect of C. oblonga fruit by enhancing the hippocampal neurogenesis in the rat model of depression.

Prenatal exposure to koumine results in cognitive deficits and increased anxiety-like behavior in mice offspring.

Koumine (KM) is a major alkaloid monomer in the traditional Chinese medicine herb Gelsemium elegans Benth that has exhibited therapeutic potential in clinical applications. However, the pharmacological toxicological mechanism of this drug has not been fully explored. The purpose of this study was to evaluate the impacts of KM administration at a therapeutic dose in offspring. On gestational day 0, mice were injected with KM once daily for 4 consecutive days. Male and female offspring were subjected to behavioral tests and neuropathological analyses from postnatal day 60. Prenatal KM exposure resulted in cognitive and memory impairments in the Morris water maze, Y-maze test, and novel object recognition test. The open field test and elevated plus maze test indicated that prenatal KM exposure induced anxiety-like behavior in offspring. Electrophysiological experiments demonstrated that KM exposure inhibited hippocampal long-term potentiation. Immunostaining for neurogenesis markers DCX and BrdU demonstrated that KM suppressed adult neurogenesis in the subgranular zone of the dentate gyrus. In addition, prenatal KM exposure induced a significant reduction in dendritic spine density in hippocampal neurons. Synaptic formation-related proteins were decreased in the KM group based on western blot. No sex differences in the effects of KM were observed. Collectively, our results indicate that prenatal KA exposure has detrimental neural effects on offspring. This study provides a preliminary preclinical toxicological assessment of the safety of KM use during pregnancy.

Radix Scutellariae Ameliorates Stress-Induced Depressive-Like Behaviors via Protecting Neurons through the TGFß3-Smad2/3-Nedd9 Signaling Pathway.

Chronic stress can impair hippocampal neurogenesis, increase neuronal apoptosis, and cause depressive-like behaviors. Our previous studies found that Radix Scutellariae (RS) can rescue the stress-induced neuronal injury, but the mechanism is not clear. Here, we continued to investigate the underlying antidepressant mechanisms of the RS extract. A 7-week chronic unpredictable mild stress (CUMS) procedure was used to establish a murine depression model. 0.75 g/kg or 1.5 g/kg RS was administered daily to the mice during the last 4 weeks. Depressive-like behaviors were evaluated by the sucrose preference test (SPT), forced swimming test (FST), open field test (OFT), and tail suspension test (TST). The neuroprotective effect of RS was evaluated with the expression of hippocampal neuron-related markers and apoptosis-associated proteins by Nissl staining, immunohistochemistry, and western blot. Transforming growth factor-ß3 (TGFß3) pathway-related proteins were detected by western blot. Results showed that RS could ameliorate depressive-like behaviors, increase the expression of the antiapoptotic protein B-cell lymphoma 2 (BCL-2), reduce the expression of the proapoptotic protein BCL-2-associated X (BAX), and increase the number of doublecortin- (DCX-), microtubule-associated protein 2- (MAP2-), and neuronal nucleus- (NeuN-) positive cells in the hippocampus. Moreover, RS could reverse the CUMS-induced decrease of TGFß3 protein, promote the phosphorylation of SMAD2/3, and increase the expression of downstream NEDD9 protein. These results suggest that RS could exert antidepressant effects via protecting neurons. And the molecular mechanism might be related to the regulation of the TGFß3-SMAD2/3-NEDD9 pathway.

A Selective P2Y Purinergic Receptor Agonist 2-MesADP Enhances Locomotor Recovery after Acute Spinal Cord Injury.

INTRODUCTION: Spinal cord injury (SCI) causes most severe motor and sensory dysfunctions. In Chinese traditional medicine, the agonist of a purinergic receptor is believed to have a positive effect on SCIs, and 2-Methylthio-adenosine-5'-diphosphate (2-MesADP) is a selective agonist of the P2Y purinergic receptor. METHODS: To investigate its therapeutic function and molecular mechanism in SCI, transcriptome analysis associated with weighted gene co-expression network analysis (WGCNA) was carried out at various time points after T9 crush injury. RESULTS: 2-MesADP demonstrated recovery of limb motor function at the 6 weeks after injury, accompanied by neuronal regeneration and axon remyelination at 2 and 6 weeks. Furthermore, gene profiling revealed alternated gene expression with the treatment of 2-MesADP. These genes were assigned to a total of 38 modules, followed by gene ontology analysis; of these, 18 represented neuronal apoptosis and regeneration, immune response, synaptic transmission, cell cycle, and angiogenesis. In the neuronal apoptosis and regeneration module, Nefh, NeuroD6, and Dcx in the 2-MesADP group were noticed due to their interesting expression pattern. The gene expression patterns of Mag, Mog, and Cnp, which played key roles in myelination, were significantly changed with the treatment of 2-MesADP. Wnt signal pathway was the most important pathway in 2-MesADP treatment for acute SCI. CONCLUSION: 2-MesADP enhanced locomotor recovery in mouse SCI by altering the expression of neuronal apoptosis and remyelination-related genes and Wnt signaling pathways.

Fat-1 expression enhance hippocampal memory in scopolamine-induced amnesia.

Omega-3 polyunsaturated fatty acids (PUFA) are critical for optimal brain health and are involved in psychiatric and neurological ailments. Here, we report the effects of higher endogenous omega-3 PUFA on memory impairment in the hippocampus by studying mice with transgenic expression of the fat-1 gene that converts omega-6 to omega-3 PUFA. We performed Y-maze and passive avoidance tests to evaluate the memory function of fat-1 mice treated with scopolamine. Fat-1 mice showed induced alternation in the Y-maze test and increased latency in the passive avoidance test. The effects of scopolamine on hippocampal neurogenesis were confirmed by increases in the number of Ki-67- and DCX-positive cells in the fat-1 mice. Western blotting revealed increased brain-derived neurotrophic factor (BDNF) and phosphorylated cAMP response element-binding protein levels, and lower scopolamine-induced apoptosis based on the cleaved-caspase 3 protein level in fat-1 mice. These findings suggest that higher endogenous omega-3 PUFA prevented granular cell loss, increased BDNF signaling, and decreased apoptosis signaling in scopolamine-treated fat-1 mice. These processes may underlie granular cell survival and suggest potential therapeutic targets for memory impairment.

Oxytocin has sex-specific effects on social behaviour and hypothalamic oxytocin immunoreactive cells but not hippocampal neurogenesis in adult rats.

Oxytocin regulates social behaviours, pair bonding and hippocampal neurogenesis but most studies have used adult males. Our study investigated the effects of oxytocin on social investigation and adult hippocampal neurogenesis in male and female rats. Oxytocin has poor penetration of the blood-brain barrier, therefore we tested a nanoparticle drug, TRIOZAN™ (Ovensa Inc.), which permits greater blood-brain-barrier penetration. Adult male and female rats were injected daily (i.p.) for 10 days with either: oxytocin in PBS (0.5 or 1.0 mg/kg), oxytocin in TRIOZAN™ (0.5 or 1.0 mg/kg), or vehicle (PBS) and tested for social investigation. Oxytocin decreased body mass and increased social investigation and number of oxytocin-immunoreactive cells in the supraoptic nucleus (SON) of the hypothalamus in male rats only. In both sexes, oxytocin decreased the number of immature neurons (doublecortin+ cells) in the ventral hippocampus and reduced plasma 17ß-estradiol levels in a dose- and delivery-dependent way. Oxytocin in TRIOZAN™ reduced "sedation" observed post-injection and increased certain central effects (oxytocin levels in the hypothalamus and neurogenesis in the ventral hippocampus) relative to oxytocin in PBS, indicating that the nanoparticle may be used as an alternative brain delivery system. We showed that oxytocin has sex-specific effects on social investigation, body mass, "sedation", and the oxytocin system. In contrast, similar effects were observed in both sexes in neurogenesis and plasma 17ß-estradiol. Our work suggests that sex differences in oxytocin regulation of brain endpoints is region-specific (hypothalamus versus hippocampus) and that oxytocin does not promote social investigation in females.

Neuroinflammation, Oxidative Stress, and Neurogenesis in a Mouse Model of Chronic Fatigue Syndrome, and the Treatment with Kampo Medicine.

The diagnosis of chronic fatigue syndrome (CFS) is mainly symptom-based, and the etiology is still unclear. Here, we evaluated the pathological changes in the brain of a mouse model of CFS and studied the effects of Kampo medicine. A mouse model of CFS was established through six repeated injections of Brucella abortus (BA) every two weeks for a period of 12 weeks. Neuroinflammation was measured by estimating interleukin (IL)-1ß, IL-6, and interferon-gamma (IFN-γ), and oxidative stress by nitrotyrosine (3-NT) and 4-hydroxynonenal (4-HNE) 6 weeks after the last injection. Hippocampal neurogenesis was evaluated through Ki-67, doublecortin (DCX), and 5-bromodeoxyuridine (BrdU) assays. The effects of Kampo medicines (Hochuekkito (TJ-41) and Hachimijiogan (TJ-7)) on neuroinflammation during CFS were studied. The wheel-running activity of mice was decreased by about 50% compared to baseline at 6 weeks after the last BA injection. The levels of IL-1ß, IL-6, 3-NT, and 4-HNE were increased in both the cortex and the hippocampus of CFS mice at 6 weeks after the last BA injection. Hippocampal neurogenesis was unchanged in CFS mice. Treatment with TJ-41 and TJ-7 reduced the expressions of IL-1ß, IL-6, and IFN-γ in the hippocampus but not in the cortex. The results of the present study indicate that neuroinflammation and oxidative stress play important roles in the pathogenesis of CFS. The data further suggest that treatment with TJ-41 and TJ-7 could help reduce the inflammation associated with CFS in the hippocampus, but failed to improve the symptoms in CFS mice.

[Effect of moxibustion on learning-memory ability and expression of hippocampal inflammatory factors and microtubule associated proteins in vascular dementia rats].

OBJECTIVE: To observe the effect of moxibustion on learning-memory ability and expression of hippocampal inflammatory factors and microtubule-associated protein doublecortin (DCX, a marker of neuronal regeneration) in vascular dementia (VD) rats, so as to explore its mechanisms underlying improvement of VD. METHODS: SD rats were randomly divided into normal control, sham operation, VD model, moxibustion and medication groups (n=15 rats in each group). The VD model was established by repeated occlusion of the bilateral common carotid arteries and reperfusion. Moxibustion was applied to "Guanyuan" (CV4), "Mingmen" (GV4) and "Dazhui"(GV14) for 15 min, once a day, 6 days a week for 4 weeks. Rats of the medication group were treated by gavage of Nimodipine (2mg·kg-1·d-1) 3 times daily for 4 weeks. Morris water maze test was used to detect the average escape latency of location navigation tasks for assessing the rats' learning-memory ability. H.E. staining was used to detect histopathological changes of the hippocampus tissue. The number of DCX-positive neurons (DCX/NeuN co-expression) in the dentate gyrus (DG) region of hippocampus was counted under microscope after immunofluorescence double staining, the immunoactivity of hippocampal DCX detected by using immunohistochemistry stain and the expression of DCX, TNF-α, IL-1ß, MPO, NF-κB p65 and IL-6 proteins in the hippocampus tissue detected using Western blot. RESULTS: Following modeling, the average escape latency was significantly longer in the model group than in the normal control and sham operation groups (P<0.01), and notably shorter in both the moxibustion and medication groups than in the model group after the treatment (P<0.01, P<0.05). The number of DCX-positive neurons, and the expression levels of DCX, TNF-α, IL-1ß, MPO, NF-κB p65 and IL-6 proteins in the hippocampus were significantly increased in the model group in comparison with the normal control and sham operation groups (P<0.01, P<0.05). After the interventions and in comparison with the model group, the number of DCX-positive neurons and the expression level of DCX were further up-regulated in both moxibustion and medication groups (P<0.01), while the expression levels of hippocampal TNF-α, IL-1ß, MPO, NF-κB p65 and IL-6 proteins were considerably down-regulated in the moxibustion and medication groups (P<0.01). The effect of moxibustion was weaker than that of medication in down-regulating the expression of TNF-α,MPO, NF-κB p65, IL-6 and IL-1ß, and in up-regulating DCX-positive neuron number and DCX expression (P<0.05, P<0.01). H.E. staining showed loose arrangement of neurons (with vague neuronal membrane in some cells), uneven organelle chromatin, disappearance of partial nucleolus, necrocytosis, and infiltration of small number of lymphocytes after modeling, which was relatively milder in both moxibustion and medication groups. CONCLUSION: Moxibustion can improve learning-memory ability in VD rats, which may be related to its effect in down-regulating the expression of inflammatory factors and up-regulating the expression of DCX to promote neuronal repair and regeneration.

[Chinese medicine Buyang Huanwu decoction promotes neurogenesis and angiogenesis in ischemic stroke rats by upregulating miR-199a-5p expression].

OBJECTIVE: To investigate the mechanism of Chinese medicine Buyang Huanwu decoction (BYHWD) promoting neurogenesis and angiogenesis in ischemic stroke rats. METHODS: Male SD rats were randomly divided into sham operation group, model group, BYHWD group, antagonist group and antagonist control group with 14 rats in each. Focal cerebral ischemia was induced by occlusion of the right middle cerebral artery for 90 min with intraluminal filament and reperfusion for 14 d in all groups except sham operation group. BYHWD (13 g/kg) was administrated by gastrogavage in BYHWD group, antagonist group and antagonist control group at 24 h after modeling respectively, and BrdU (50 mg/kg) was injected intraperitoneally in all groups once a day for 14 consecutive days. miR-199a-5p antagomir or NC (10 nmol) was injected into the lateral ventricle at d5 after ischemia in antagonist and antagonist control groups, respectively. The neurological deficits were evaluated by the modified neurological severity score (mNSS) and the corner test, and the infract volume was measured by toluidine blue staining. Neurogenesis and angiogenesis were detected by immunofluorescence double labeling method. The expression level of miR-199a-5p was tested by real-time RT-PCR, and the protein expressions of vascular endothelial growth factor (VEGF) and brain-derived neurotrophic factor (BDNF) were determined by Western blotting. RESULTS: BYHWD treatment significantly promoted the recovery of neurological function (P<0.05 or P<0.01), reduced the infarct volume (P<0.05), increased the number of BrdU+/DCX+, BrdU+/NeuN+ and BrdU+/vWF+ cells (all P<0.01), upregulated the expression of miR-199a-5p (P<0.01), and increased the protein expression of VEGF and BDNF at d14 after cerebral ischemia (all P<0.05). The above effects were reversed by intracerebroventricular injection of miR-199a-5p antagomir. CONCLUSIONS: Buyang Huanwu decoction promotes neurogenesis and angiogenesis in rats with cerebral ischemia, which may be related to increased protein expression of VEGF and BDNF through upregulating miR-199a-5p.

Ligusticum chuanxiong exerts neuroprotection by promoting adult neurogenesis and inhibiting inflammation in the hippocampus of ME cerebral ischemia rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Cerebral ischemia, also known as stroke, can stimulate the proliferation and migration of endogenous neural stem cells (NSCS) in subventricular zone of the lateral ventricle and subgranularzone of the dentate gyrus in the adult hippocampus as a defense response to damage. However, the proliferation of endogenous NSCS is insufficient for central nervous system repair. Neurogenesis and anti-neuroinflammation are two important aspects for neuroprotection. Rhizome Ligusticum chuanxiong (LC), the dried rhizomes of Ligusticum striatum DC., has been widely used to treat stroke for over hundreds of years in Traditional Chinese Medicine. PURPOSE: of the study: Previous reports on pharmacological mechanism of LC mainly focus on the cerebral blood flow and thrombolysis. We aim to explore whether LC provides neuroprotective effect by increasing neurogenesis and inhibiting the IL-1ß, TNF-α and expressions of glial fibrillary acidic protein. MATERIALS AND METHODS: LC extract was delivered to microsphere-embolized (ME) cerebral ischemia Wister rats to examine its neuroprotection. Body weight, neurological scores, hematoxylin-eosin staining (HE), TUNEL assay were conducted for neurological damage. Neurogenesis was evaluated by assessing the expression of Doublecortin (DCX) and neurogenic differentiation1 (NeuroD1) through immunofluorescence staining. Western blot performed to measure the protein levels of growth associated protein-43(GAP-43), glial fibrillary acidic protein (GFAP). IL-1ß and TNF-α was detected by Elisa. RESULTS: LC alleviated pathomorphological change and apoptosis of neurons in the hippocampus caused by ME surgery. Furthermore, LC significantly increased the DCX in the DG of adult rat hippocampus at 14 days after surgery. A significant upregulation of GAP-43 compared to the ME after LC was administered. Besides, LC decreased pro-inflammatory cytokine (IL-1ß, TNF-α) and protein level of GFAP. CONCLUSION: The finding suggested that LC had the ability to protect neurons by promoting the endogenous proliferation of neuroblast and production of neural differentiation factor in rats after ischemia injury. Meanwhile, LC can anti-neuroinflammation, which is important for the treatment of neuron injury. Accordingly, LC perhaps a promising medicine for neuron damage therapy after cerebral ischemia.

Safety evaluation and protective effects of ethanolic extract from maca (Lepidium meyenii Walp.) against corticosterone and H2O2 induced neurotoxicity.

Maca has been traditionally used to enhance sexual behavior and fertility. Recently, maca's neuroprotective effects have been reported. The purpose of this study was to investigate whether the ethanol extract of maca (EEM) (100 mg/kg/bw, 200 mg/kg/bw, 400 mg/kg/bw, p.o.) exerted neuroprotective effects in corticosterone (CORT)-induced (40 mg/kg/bw, s.c.) rats, to determine the neuroprotective effects of EEM (12.5, 25, 50 µg/ml) and macamides in H2O2-induced (50 µM) PC12 cells. The acute toxicity (2000 mg/kg/bw, p.o.) and subacute toxicity (200 mg/kg/bw, 500 mg/kg/bw, 1000 mg/kg/bw, p.o.) of EEM were evaluated by mouse models. EEM reversed CORT-induced abnormal behaviors, reduced the contents of TNF-α, IL-6 in hippocampi, and increased the positive cells of doublecortin (DCX), bromodeoxyuridine (BrdU) and DCX + BrdU in the hippocampus of rats. Moreover, EEM and 4 macamides remarkably increased the cell viability in H2O2-induced PC12 cells. EEM promoted the phosphorylation of IκBα and p65, suppressed the NF-κB activation, and inhibited the levels of pro-inflammatory cytokines such as TNF-α, IL-6 and their mRNA levels in H2O2-induced PC12 cells. In conclusion, EEM could exert neuroprotective effects in CORT-induced rats and in H2O2-induced PC12 cells. Moreover, EEM did not present relevant toxicity after exposure to single and repeated doses.

Mahuang-Fuzi-Xixin Decoction Reverses Depression-Like Behavior in LPS-Induced Mice by Regulating NLRP3 Inflammasome and Neurogenesis.

Evidence suggests that inflammation and neurogenesis play an important role in major depressive disorder (MDD). Mahuang-Fuzi-Xixin decoction (MFX), as the traditional Chinese prescription, has been widely applied for asthma, migraine, and MDD in clinics. However, the effects of MFX on the potential mechanism in MDD are still unclear. Hence, the present study is aimed at exploring whether the antidepressive effect of MFX is connected to the anti-inflammatory and promoting neurogenesis. Besides, lipopolysaccharide (LPS) of Gram-negative bacteria can induce depressive-like behaviors. We demonstrated that administration of MFX corrected the depressive-like behaviors in LPS-induced mice and significantly decreased the expression of IL-1ß in the hippocampus. LPS injection induced a significant increase in the levels of NLRP3, cleaved caspase-1 p20, and ASC in the hippocampus, as well as Trx-interacting protein (TXNIP), and MFX could reverse this change. What is more, treatment of MFX increased the level of doublecortin (DCX), brain-derived neurotrophic factor (BDNF), and tropomyosin-related kinase receptor B (TrkB) in the hippocampus which means that MFX could promote the neurogenesis. In conclusion, the study indicates that MFX relieves a depressive-like state in LPS-induced mice through the inhibition of the NLRP3 inflammasome and the enhancement of the neurogenesis pathway.

Folic acid, but not folate, regulates different stages of neurogenesis in the ventral hippocampus of adult female rats.

Folate is an important regulator of hippocampal neurogenesis, and folic acid is needed prenatally to reduce the risk of neural tube defects. Both high levels of folic acid and low levels of folate can be harmful to health because low levels of folate have been linked to several diseases while high folic acid supplements can mask a vitamin B12 deficiency. Depressed patients exhibit folate deficiencies, lower levels of hippocampal neurogenesis, elevated levels of homocysteine and elevated levels of the stress hormone, cortisol, which may be inter-related. In the present study, we were interested in whether different doses of natural folate or synthetic folic acid diets can influence neurogenesis in the hippocampus, levels of plasma homocysteine and serum corticosterone in adult female rats. Adult female Sprague-Dawley rats underwent dietary interventions for 29 days. Animals were randomly assigned to six different dietary groups: folate deficient + succinylsulphathiazole (SST), low 5-methyltetrahydrofolate (5-MTHF), low 5-MTHF + (SST), high 5-MTHF + SST, low folic acid and high folic acid. SST was added to a subset of the 5-MTHF diets to eliminate folic acid production in the gut. Before and after dietary treatment, blood samples were collected for corticosterone and homocysteine analysis, and brain tissue was collected for neurogenesis analysis. High folic acid and low 5-MTHF without SST increased the number of immature neurones (doublecortin-expressing cells) within the ventral hippocampus compared to folate deficient controls. Low 5-MTHF without SST significantly increased the number of immature neurones compared to low and high 5-MTHF + SST, indicating that SST interfered with elevations in neurogenesis. Low folic acid and high 5-MTHF + SST reduced plasma homocysteine levels compared to controls, although there was no significant effect of diet on serum corticosterone levels. In addition, low folic acid and high 5-MTHF + SST reduced the number of mature new neurones in the ventral hippocampus (bromodeoxyuridine/NeuN-positive cells) compared to folate deficient controls. Overall, folic acid dose-dependently influenced neurogenesis with low levels decreasing but high levels increasing neurogenesis in the ventral hippocampus, suggesting that this region, which is important for regulating stress, is particularly sensitive to folic acid in diets. Furthermore, the addition of SST negated the effects of 5-MTHF to increase neurogenesis in the ventral hippocampus.

Roman chamomile inhalation combined with clomipramine treatment improves treatment-resistant depression-like behavior in mice.

It is well known that chamomile is one of the oldest known medicinal herbs and has been used to treat various disorders, but it is mainly German chamomile. The effects of Roman chamomile on depression still unclear. In this study, we used chronically stressed mice to investigate whether inhalation of Roman chamomile essential oil affects depression-like behavior. We previously reported that restraint and water immersion stress produce depression-like behavior and a blunted response to the tricyclic antidepressant clomipramine. Each mouse was exposed to restraint and water immersion stress for 15 days, and resistance to the effect of clomipramine was induced in a behavioral despair paradigm. In the present study, we found that cotreatment with clomipramine and inhalation of Roman chamomile attenuated depression-like behavior in a forced swim test. Next, we examined the hippocampal mRNA levels of two cytokines, tumor necrosis factor (TNF) alpha and interleukin-6 (IL-6); a neurotrophic factor, brain derived-neurotrophic factor (BDNF); and nerve growth factor (NGF). TNF alpha, IL-6 and BDNF mRNA levels did not change in the hippocampus of stressed mice. However, the NGF mRNA level was significantly decreased, and this decrease was not attenuated by treatment with clomipramine or inhalation of Roman chamomile alone. We also examined whether Roman chamomile combined with clomipramine treatment affects hippocampal neurogenesis and serum corticosterone levels. Stressed mice had fewer doublecortin (DCX)-positive cells in the subgranular zone of the dentate gyrus, but this was significantly attenuated by Roman chamomile and clomipramine treatment. In addition, the serum corticosterone level was also significantly decreased by treatment with Roman chamomile and clomipramine. These results suggest that Roman chamomile inhalation may enhance the antidepressant effect of clomipramine by increasing hippocampal neurogenesis and modulating corticosterone levels in patients with treatment-resistant depression.

Ergostatrien-7,9(11),22-trien-3ß-ol from Antrodia camphorata ameliorates ischemic stroke brain injury via downregulation of p65NF-κ-B and caspase 3, and activation of Akt/GSK3/catenin-associated neurogenesis.

Antrodia camphorata is a well-known traditional Chinese mushroom used as a functional food and nutraceutical in Taiwan and China. The aim of this study was to explore the protective effects and mechanism(s) of the ethyl acetate crude extract of A. camphorata (EtOAc-AC) and its active constituent ergostatrien-7,9(11),22-trien-3ß-ol (EK100) in an acute ischemic stroke (AIS) murine model. Treating mice with induced AIS injury by using EtOAc-AC (0.3-0.6 g kg-1, p.o.) and EK100 (60 and 120 mg kg-1, p.o.) 2 h after AIS induction significantly increased the tracking distance and reduced brain infarction. Both EtOAc-AC and EK-100 reduced the expression levels of p65NF-κB and caspase 3 near the peri-infarct cortex and promoted the expression of neurogenesis-associated protein doublecortin (DCX) near the hippocampus, accompanied by glycogen synthase kinase 3 (GSK-3) inhibition and ß-catenin upregulation. Signaling pathway analysis revealed that the advantageous effects of EtOAc-AC and EK-100 involved triggering the activation of PI3K/Akt and inhibition of GSK-3. Our findings suggest that EtOAc-AC and its active constituent EK100 display anti-inflammatory and anti-apoptotic activities. Both EtOAc-AC and EK100 reduce ischemic brain injury by decreasing p65NF-κB and caspase 3 expression, and they promote neurogenesis (DCX) and neuroprotection (Bcl2) by activating the PI3k/Akt-associated GSK3 inhibition and ß-catenin activation.

Dietary fructose-induced gut dysbiosis promotes mouse hippocampal neuroinflammation: a benefit of short-chain fatty acids.

BACKGROUND: Western-style diets arouse neuroinflammation and impair emotional and cognitive behavior in humans and animals. Our previous study showed that a high-fructose diet caused the hippocampal neuroinflammatory response and neuronal loss in animals, but the underlying mechanisms remained elusive. Here, alterations in the gut microbiota and intestinal epithelial barrier were investigated as the causes of hippocampal neuroinflammation induced by high-fructose diet. RESULTS: A high-fructose diet caused the hippocampal neuroinflammatory response, reactive gliosis, and neuronal loss in C57BL/6N mice. Depletion of the gut microbiota using broad-spectrum antibiotics suppressed the hippocampal neuroinflammatory response in fructose-fed mice, but these animals still exhibited neuronal loss. Gut microbiota compositional alteration, short-chain fatty acids (SCFAs) reduction, intestinal epithelial barrier impairment, NOD-like receptor family pyrin domain-containing 6 (NLRP6) inflammasome dysfunction, high levels of serum endotoxin, and FITC-dextran were observed in fructose-fed mice. Of note, SCFAs, as well as pioglitazone (a selective peroxisome proliferator-activated receptor gamma (PPAR-γ) agonist), shaped the gut microbiota and ameliorated intestinal epithelial barrier impairment and NLRP6 inflammasome dysfunction in fructose-fed mice. Moreover, SCFAs-mediated NLRP6 inflammasome activation was inhibited by histamine (a bacterial metabolite) in ex vivo colonic explants and suppressed in murine CT26 colon carcinoma cells transfected with NLRP6 siRNA. However, pioglitazone and GW9662 (a PPAR-γ antagonist) exerted no impact on SCFAs-mediated NLRP6 inflammasome activation in ex vivo colonic explants, suggesting that SCFAs may stimulate NLRP6 inflammasome independently of PPAR-γ activation. SCFAs and pioglitazone prevented fructose-induced hippocampal neuroinflammatory response and neuronal loss in mice. Additionally, SCFAs activated colonic NLRP6 inflammasome and increased DCX+ newborn neurons in the hippocampal DG of control mice. CONCLUSIONS: Our findings reveal that gut dysbiosis is a critical factor for a high-fructose diet-induced hippocampal neuroinflammation in C57BL/6N mice possibly mediated by impairing intestinal epithelial barrier. Mechanistically, the defective colonic NLRP6 inflammasome is responsible for intestinal epithelial barrier impairment. SCFAs can stimulate NLRP6 inflammasome and ameliorate the impairment of intestinal epithelial barrier, resulting in the protection against a high-fructose diet-induced hippocampal neuroinflammation and neuronal loss. This study addresses a gap in the understanding of neuronal injury associated with Western-style diets. A new intervention strategy for reducing the risk of neurodegenerative diseases through SCFAs supplementation or dietary fiber consumption is emphasized.

Leaf extracts from Dendropanax morbifera Léveille mitigate mercury-induced reduction of spatial memory, as well as cell proliferation, and neuroblast differentiation in rat dentate gyrus.

BACKGROUND: The brain is susceptible to methylmercury toxicity, which causes irreversible damage to neurons and glia and the leaf extract Dendropanax morbifera Léveille (DML) has various biological functions in the nervous system. In this study, we examined the effects of DML on mercury-induced proliferating cells and differentiated neuroblasts. METHODS: Dimethylmercury (5 µg/kg) and galantamine (5 mg/kg) was administered intraperitoneally and/or DML (100 mg/kg) was orally to 7-week-old rats every day for 36 days. One hour after the treatment, novel object recognition test was examined. In addition, spatial probe tests were conducted on the 6th day after 5 days of continuous training in the Morris swim maze. Thereafter, the rats were euthanized for immunohistochemical staining analysis with Ki67 and doublecortin and measurement for acetylcholinesterase (AChE) activity. RESULTS: Dimethylmercury-treated rats showed reduced discrimination index in novel object recognition test and took longer to find the platform than did control group. Compared with dimethylmercury treatment alone, supplementation with DML or galatamine significantly ameliorated the reduction of discrimination index and reduced the time spent to find the platform. In addition, the number of platform crossings was lower in the dimethylmercury-treated group than in controls, while the administration of DML or galantamine significantly increased the number of crossings than did dimethylmercury treatment alone. Proliferating cells and differentiated neuroblasts, assessed by Ki67 and doublecortin immunohistochemical staining was significantly decreased in the dimethylmercury treated group versus controls. Supplementation with DML or galantamine significantly increased the number of proliferating cells and differentiated neuroblasts in the dentate gyrus. In addition, treatment with dimethylmercury significantly increased AChE activity in hippocampal homogenates, while treatment with dimethylmercury+DML or dimethylmercury+galantamine significantly ameliorated this increase. CONCLUSIONS: These results suggest that DML may be a functional food that improves dimethylmercury-induced memory impairment and ameliorates dimethylmercury-induced reduction in proliferating cells and differentiated neuroblasts, and demonstrates corresponding activation of AChE activity in the dentate gyrus.

Chronic aromatase inhibition increases ventral hippocampal neurogenesis in middle-aged female mice.

Letrozole, a third-generation aromatase inhibitor, prevents the production of estrogens in the final step in conversion from androgens. Due to its efficacy at suppressing estrogens, letrozole has recently taken favor as a first-line adjuvant treatment for hormone-responsive breast cancer in middle-aged women. Though patient response to letrozole has generally been positive, there is conflicting evidence surrounding its effects on the development of depression. It is possible that the potential adverse effects of letrozole on mood are a result of the impact of hormonal fluctuations on neurogenesis in the hippocampus. Thus, to clarify the effects of letrozole on the hippocampus and behavior, we examined how chronic administration affects hippocampal neurogenesis and depressive-like behavior in middle-aged, intact female mice. Mice were given either letrozole (1 mg/kg) or vehicle by injection (i.p.) daily for 3 weeks. Depressive-like behavior was assessed during the last 3 days of treatment using the forced swim test, tail suspension test, and sucrose preference test. The production of new neurons was quantified using the immature neuronal marker doublecortin (DCX), and cell proliferation was quantified using the endogenous marker Ki67. We found that letrozole increased DCX and Ki67 expression and maturation in the dentate gyrus, but had no significant effect on depressive-like behavior. Our findings suggest that a reduction in estrogens in middle-aged females increases hippocampal neurogenesis without any adverse impact on depressive-like behavior; as such, this furthers our understanding of how estrogens modulate neurogenesis, and to the rationale for the utilization of letrozole in the clinical management of breast cancer.