Animals ; Apoptosis ; Cognition ; Diabetes Mellitus, Experimental/drug therapy* ; Drugs, Chinese Herbal/pharmacology* ; Hippocampus/cytology* ; Moringa/chemistry* ; Neurons/drug effects* ; Plant Leaves/chemistry* ; Rats ; Rats, Sprague-Dawley

BackgroundGlehnia littoralis has been used for traditional Asian medicine, which has diverse therapeutic activities. However, studies regarding neurogenic effects of G. littoralis have not yet been considered. Therefore, in this study, we examined effects of G. littoralis extract on cell proliferation, neuroblast differentiation, and the maturation of newborn neurons in the hippocampus of adult mice.

MethodsA total of 39 male ICR mice (12 weeks old) were randomly assigned to vehicle-treated and 100 and 200 mg/kg G. littoralis extract-treated groups (n = 13 in each group). Vehicle and G. littoralis extract were orally administrated for 28 days. To examine neurogenic effects of G. littoralis extract, we performed immunohistochemistry for 5-bromo-2-deoxyuridine (BrdU, an indicator for cell proliferation) and doublecortin (DCX, an immature neuronal marker) and double immunofluorescence staining for BrdU and neuronal nuclear antigen (NeuN, a mature neuronal marker). In addition, we examined expressional changes of brain-derived neurotrophic factor (BDNF) and its major receptor tropomyosin-related kinase B (TrkB) using Western blotting analysis.

ResultsTreatment with 200 mg/kg, not 100 mg/kg, significantly increased number of BrdU-immunoreactive () and DCX cells (48.0 ± 3.1 and 72.0 ± 3.8 cells/section, respectively) in the subgranular zone (SGZ) of the dentate gyrus (DG) and BrdU/NeuN cells (17.0 ± 1.5 cells/section) in the granule cell layer as well as in the SGZ. In addition, protein levels of BDNF and TrkB (about 232% and 244% of the vehicle-treated group, respectively) were significantly increased in the DG of the mice treated with 200 mg/kg of G. littoralis extract.

ConclusionG. littoralis extract promots cell proliferation, neuroblast differentiation, and neuronal maturation in the hippocampal DG, and neurogenic effects might be closely related to increases of BDNF and TrkB proteins by G. littoralis extract treatment.

Animals ; Apiaceae ; chemistry ; Blotting, Western ; Brain-Derived Neurotrophic Factor ; metabolism ; Cell Differentiation ; drug effects ; Cell Proliferation ; drug effects ; Dentate Gyrus ; cytology ; drug effects ; Hippocampus ; cytology ; drug effects ; Immunohistochemistry ; Male ; Mice ; Microtubule-Associated Proteins ; metabolism ; Neurogenesis ; drug effects ; Neuropeptides ; metabolism ; Plant Extracts ; pharmacology ; Receptor, trkB ; metabolism

OBJECTIVETo investigate the effect of aluminum exposure on neuronal apoptosis of rats hippocampus and the correlation of and synaptic plasticity.

METHODSThere were 40 SPF grade SD rats which were randomly divided into four groups: the control group, the low dose group, the medium dose group and the high dose group, 10 rats in each group. The rats were daily gavaged with aluminum lactate for 30 days. The hippocampal fEPSPs in rat was measured by electrophysiological grapher and the neuronal apoptosis in hippocampus was detected by Flow cytometer. In addition, the relative expression of gene which includes caspase-3, 8, 9 was measured by Real-time PCR.

RESULTSCompared to the control group, the average of fEPSPs which after HFS 10, 20, 30, 40, 50, 60 min was decreased at different time point in the low dose group, the medium dose group and the high dose group (P < 0.05). Compared with the control group, the rate of apoptosis was significantly increased in the medium dose group and the high dose group (P < 0.05). Compared to the control group, the relative expression of caspase-3 in the medium dose group and the high dose group was significantly increased in Real-time PCR (P < 0.05), and the relative expression of caspase-8 in the high dose group was significantly increased (P < 0.05).

CONCLUSIONAluminum exposure may induced neuronal apoptosis in rats, and then affect hippocampal synaptic plasticity.

Aluminum ; toxicity ; Aluminum Compounds ; toxicity ; Animals ; Apoptosis ; Caspase 3 ; metabolism ; Caspase 8 ; metabolism ; Hippocampus ; cytology ; drug effects ; Lactates ; toxicity ; Neuronal Plasticity ; drug effects ; Neurons ; cytology ; drug effects ; Rats ; Rats, Sprague-Dawley

The possible role of minocycline in microglial activation and neuronal death after cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) in mice was investigated in this study. The mice were given potassium chloride to stop the heart beating for 8 min to achieve CA, and they were subsequently resuscitated with epinephrine and chest compressions. Forty adult C57BL/6 male mice were divided into 4 groups (n=10 each): sham-operated group, CA/CPR group, CA/CPR+minocycline group, and CA/CPR+vehicle group. Animals in the latter two groups were intraperitoneally injected with minocycline (50 mg/kg) or vehicle (normal saline) 30 min after recovery of spontaneous circulation (ROSC). Twenty-four h after CA/CPR, the brains were removed for histological evaluation of the hippocampus. Microglial activation was evaluated by detecting the expression of ionized calcium-binding adapter molecule-1 (Iba1) by immunohistochemistry. Neuronal death was analyzed by hematoxylin and eosin (H&E) staining and the levels of tumor necrosis factor-alpha (TNF-α) in the hippocampus were measured by enzyme-linked immunosorbent assay (ELISA). The results showed that the neuronal death was aggravated, most microglia were activated and TNF-α levels were enhanced in the hippocampus CA1 region of mice subjected to CA/CPR as compared with those in the sham-operated group (P<0.05). Administration with minocycline 30 min after ROSC could significantly decrease the microglial response, TNF-α levels and neuronal death (P<0.05). It was concluded that early administration with minocycline has a strong therapeutic potential for CA/CPR-induced brain injury.
Animals ; Cardiopulmonary Resuscitation ; Cell Death ; drug effects ; Enzyme-Linked Immunosorbent Assay ; Heart Arrest ; pathology ; Hippocampus ; cytology ; drug effects ; metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Microglia ; cytology ; drug effects ; Minocycline ; pharmacology ; Neurons ; drug effects ; Tumor Necrosis Factor-alpha ; metabolism

OBJECTIVETo observe the effect of synchronous perfusion of specific respiratory chain complex IV inhibitor sodium azide (NaN3) in brain on rat ventromedial prefrontal cortex (mPFC) and acetylcholine (ACh) and choline (Ch) contents in hippocampal extra-cellular fluid, and establish the AD rat model induced by mitochondrial acute injury.

METHODThe synchronous dual-probe dual-channel brain microdialysis sampling technology was applied to synchronously perfuse modified Ringer's solution containing NaN3 (50 micro mol L-1) and neostigmine (2 micro mol L-1) into mPFC and hippocampus of conscious, freely moving normal rats, and continuously collect dialysates from different encephalic areas. Dynamic contents of ACh and Ch were determined by high performance liquid chromatography-post-column immobilized enzyme reactor-electrochemical process.

RESULTACh and Ch contents in mPFC extracellular fluid of normal rats were higher than that in hippocampus. During the process of perfusion, NaN3 could significantly reduce ACh in mPFC/hippocampal extra-cellular fluid, but remarkably increase Ch, and constantly inhibit the recovery of ACh and Ch contents in mPFC/hippocampus.

CONCLUSIONThe synchronous perfusion of NaN3in rat mPFC and hippocampus can injure functions of the cholinergic nerve projection area, and cause the acute AD model with ACh and Ch metabolic disorders. This model can be used in pathogenetic and pharmacological studies.

Acetylcholine ; metabolism ; Animals ; Choline ; metabolism ; Extracellular Fluid ; drug effects ; metabolism ; Hippocampus ; cytology ; Male ; Neurotransmitter Agents ; metabolism ; Perfusion ; Prefrontal Cortex ; cytology ; Rats ; Rats, Sprague-Dawley ; Sodium Azide ; administration & dosage ; pharmacology ; Time Factors

OBJECTIVETo investigate the effect of curcumin on the injury in hippocampal neurons and the expression of regulated upon activation nonnal T-cell expressed and secreted (RANTES) in hippocamp during cerebral ischemia/reperfusion (I/R) in rats with spontaneous hypertension (SH).

METHODSMale Wistar-Kyoto (WKY) rats and spontaneous hypertension rats (SHR) were randomly divided into five groups (n = 6): sham group (W-Sham and S-Sham group), ischemia/reperfusion group (W-/R and S/R group), curcumin group (S-Cur group) . Each group was splitted into 5 subgroups of 3 h,12 h, 1 d, 3 d and 7 d according to the time interval before reperfusion. Global brain ischemia/reperfusion model was established by 4-VO method. Hematoxylin-eosin staining (HE staining) was used to observe the vertebral cell morphology in hippocampal CA1 region. Nissl staining was applied to detect the average density of cone cells in hippocampal CA1 region. The expression of RANTES in hippocamp was determined by ELISA. The behavior of the rats was evaluated at 7 days after reperfusion. Results: Compared with the sham group rats, the ability of learning and memory was significantly decreased in ischemia/reperfusion group rats, the number of injured neurons were greatly elevated , the protein expression levels of RANTES was significantly increased (P < 0.05). Compared with W-I/R group rats, the ability of learning and memory in S-I/R group rats was greatly reduced, the number of injured neurons increased extremely, the protein expression level of RANTES was significantly enhanced( P <0.05). The number of injured neurons declined significantly in S-Cur group rats, the ability to learn and remember of these rats was improved and the RANTES protein content decreased significantly (P < 0.05).

CONCLUSIONSHR are more susceptible to ischemia/reperfusion induced hippocampal neuronal injury which may be improved by curcu min. Its underlying mechanism is possibly associated with the inhibition of RANTES protein expression level.

Animals ; Brain Ischemia ; metabolism ; pathology ; physiopathology ; Chemokine CCL5 ; metabolism ; Cognition ; drug effects ; Curcumin ; pharmacology ; Hippocampus ; cytology ; metabolism ; pathology ; Hypertension ; metabolism ; pathology ; physiopathology ; Male ; Neurons ; drug effects ; metabolism ; pathology ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY ; Reperfusion Injury ; metabolism

OBJECTIVETo determine the effects of 5-hydroxymethyl furfural (5-HMF), an extract of Rehmannia glutinosa Libosch, on several down-regulated signaling molecules involved in learning and memory in hippocampal neurons.

METHODSAfter cultured for 7 days, primary hippocampal neurons were divided into 5 groups: normal, corticosterone model, RU38486, 5-HMF, and donepezil group. Neuron survival rates were calculated 24 h later using SYTO13-PI double-fluorescence staining and an 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. β-galactosidase activity was also assayed. Protein expressed by the glucocorticoid receptor (GCR), brainderived neurotrophic factor (BDNF), and N-methyl-D-aspartate receptor 2B (NR2B), as well as phosphorylationcyclic adenosine monophosphate (cAMP) response element binding protein (p-CREB), phosphorylation-extracellular signal-regulated kinase (p-ERK), and phosphorylation-synapsin (p-synapsin) were quantified with Western blot.

RESULTSHippocampal neuron survival rates and the above-mentioned proteins were dramatically decreased (P<0.05), β-galactosidase activity was significantly increased in the model group. but the effect was reversed by 5-HMF, RU38486, and to a lesser extent by donepezil (P<0.05).

CONCLUSION5-HMF extracts from the Chinese herb Rehmannia glutinosa Libosch could protect hippocampal neurons from glucocorticoid injury and from down-regulated signaling molecules in the GCR-BDNF-NR2B-p-ERK-p-CREB-p-synapsin signal transduction pathway.

Animals ; Blotting, Western ; Corticosterone ; pharmacology ; Furaldehyde ; analogs & derivatives ; isolation & purification ; pharmacology ; Hippocampus ; cytology ; drug effects ; Learning ; drug effects ; Memory ; drug effects ; Neurons ; drug effects ; Rats ; Rats, Sprague-Dawley ; Rehmannia ; chemistry ; Signal Transduction ; drug effects

BACKGROUNDBrain dysfunction is a frequent complication of sepsis, usually defined as sepsis-associated encephalopathy (SAE). Although the Notch signaling pathway has been proven to be involved in both ischemia and neuronal proliferation, its role in SAE is still unknown. Here, the effect of the Notch signaling pathway involved γ-secretase inhibitor DAPT on SAE in septic rats was investigated in a cecal ligation and puncture (CLP) model.

METHODSFifty-nine Sprague-Dawley rats were randomly divided into four groups, with the septic group receiving the CLP operation. Twenty-four hours after CLP or sham treatment, rats were sacrificed and their hippocampus was harvested for Western blot analysis. TNF-α expression was determined using an enzyme-linked immunosorbent assay (ELISA) kit. Neuronal apoptosis was assessed by TUNEL staining, and neuronal cell death was detected by H&E staining. Finally, a novel object recognition experiment was used to evaluate memory impairment.

RESULTSOur data showed that sepsis can increase the expression of hippocampal Notch receptor intracellular domain (NICD) and poly (adenosine diphosphate [ADP]-ribose) polymerase-1 (PARP-1), as well as the inflammatory response, neuronal apoptosis, neuronal death, and memory dysfunction in rats. The γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-1-alanyl]-S-phenylglycine t-butyl ester (DAPT) can significantly decrease the level of NICD and PARP-1, reduce hippocampal neuronal apoptosis and death, attenuate TNF-α release and rescue cognitive impairment caused by CLP.

CONCLUSIONThe neuroprotective effect of DAPT on neuronal death and memory impairment in septic rats, which could be a new therapeutic approach for treating SAE in the future.

Amyloid Precursor Protein Secretases ; antagonists & inhibitors ; Animals ; Apoptosis ; drug effects ; Dipeptides ; therapeutic use ; Hippocampus ; drug effects ; metabolism ; Male ; Neurons ; cytology ; drug effects ; Neuroprotective Agents ; Poly (ADP-Ribose) Polymerase-1 ; Poly(ADP-ribose) Polymerases ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, Notch ; metabolism ; Sepsis ; complications ; Sepsis-Associated Encephalopathy ; drug therapy ; enzymology ; Signal Transduction ; drug effects

OBJECTIVETo study the effect of ginsenoside Rb1 on GSKbeta/IDE signal transduction pathway and Abeta protein secretion in hippocampal neurons of high glucose-treated rats.

METHODHippocampal neurons of 24 h-old newly born SD rats were primarily cultured, inoculated in culture medium under different conditions, and then divided into the normal group, the high glucose group, the LiCl group and the Rb1 group. After being cultured for 72 h, the expressions of their phosphorylated GSK3beta, total GSK3beta and IDE protein were detected by Western blotting analysis. The mRNA expressions of GSK3beta and IDE were determined by RT-PCR. The ELISA assay was used to detect the secretion of Abeta protein in cell supernatant.

RESULTCompared with the normal group, the high glucose group showed increase in the p/tGSK3beta protein ratio and the secretion of Abeta protein and decrease in IDE protein and mRNA (P < 0.05). Compared with the high glucose group, both Rb1 and LiCl groups showed decrease in the p/tGSK3beta protein ratio and the expression of Abeta protein and increase in IDE protein and mRNA expression (P < 0.05). Compared with the LiCl group, the Rb1 group showed no significant difference in the expressions of p/tGSK3beta protein, IDE protein, mRNA and Abeta protein expression. In addition, the GSK3beta mRNA expression of the four groups had no significant difference.

CONCLUSIONGinsenoside Rb1 may reduce the secretion of Abeta protein in hippocampal neurons by reducing the phosphorylation of GSK3beta, down-regulating the ratio of pGSK3beta/GSK3beta and upregulating the expression of IDE.

Amyloid beta-Peptides ; genetics ; metabolism ; secretion ; Animals ; Dietary Carbohydrates ; adverse effects ; Gene Expression Regulation ; drug effects ; Ginsenosides ; pharmacology ; Glucose ; adverse effects ; Glycogen Synthase Kinase 3 ; genetics ; metabolism ; Glycogen Synthase Kinase 3 beta ; Hippocampus ; cytology ; Insulin ; metabolism ; Insulysin ; genetics ; metabolism ; Neurons ; cytology ; drug effects ; metabolism ; secretion ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; drug effects

OBJECTIVETo observe the effects of subchronic exposure to benzo[a]pyrene (B[a]P) on the mRNA and protein expression levels of apoptosis-related genes (bax, bcl-2, caspase-3, caspase-6, and caspase-9) and the activities of Caspase-3, Caspase-6, and Caspase-9 in the hippocampal neurons of rats and to investigate the neurotoxic mechanism by which B[a]P induces the apoptosis of neurons.

METHODSFifty-two healthy SD rat were randomly divided into five groups according to preliminary neurobehavioral test results: blank control group, solvent control group, and 1.0, 2.5, and 6.25 mg/kg B[a]P exposure groups; the rats in exposure groups were intraperitoneally injected with B[a]P every other day for 90 days. The Morris water maze was used to test the learning and memory ability of rats; flow cytometry was used to measure the apoptosis ratio of hippocampal neurons; real-time quantitative PCR and Western blot were used to measure the mRNA and protein expression levels of apoptosis-related genes; spectrophotometry was used to measure the activities of their en-coded proteins.

RESULTSCompared with the blank control group, solvent control group, and 1.0 mg/kg B[a]P exposure group, the 2.5 and 6.25 mg/kg B[a]P exposure groups hada significantly longer mean escape latency period (P < 0.05) and a significantly increased number of times of platform crossing (P < 0.05), and the 6.25 mg/kg B[a]P exposure group had significantly lower length and percentage of time spent in the platform quadrant (P < 0.05). The early apoptosis ratio rose as the dose of B[a]P increased (P trend < 0.05); the early apoptosis ratios of 1.0, 2.5, and 6.25 mg/kg B[a]P exposure groups were significantly higher than those of blank control group and solvent control group (P < 0.05). Compared with the blank control group, solvent control group, and 1.0 and 2.5 mg/kg B[a]P exposure groups, the 6.25 mg/kg B[a]P exposure group had significantly increased Bax expression (P < 0.05) and significantly decreased Bcl-2 expression and Bcl-2/Bax ratio (P < 0.05). The 2.5 and 6.25 mg/kg B[a]P exposure groups had significantly higher expression levels of Caspase-3 and Caspase-6 than the blank control group, solvent control group, and 1.0 mg/kg B[a]P exposure group (P < 0.05). The activities of Caspase-3, Caspase-6, and Caspase-9 were significantly higher in the 2.5 and 6.25 mg/kg B[a]P exposure groups than in the blank control group and solvent control group (P < 0.05). There was a positive correlation between the activities of Caspase-3, Caspase-6, and Caspase-9 and early apoptosis ratio of hippocampal neurons in rats (r = 0.793, P = 0.019; r = 0.886, P = 0.006; r = 0.773, P = 0.025). There were no significant differences in the mRNA expression of Bax, Bcl-2, Caspase-3, Caspase-6, and Caspase-9 among these groups (P > 0.05).

CONCLUSIONSubchronic exposure to B[a]P can induce apoptosis of hippocampal neurons; its mechanism may be related to the fact that B[a]P can induce upregulated expression of Bax, inhibit expression of Bcl-2, lead to decrease in Bcl-2/Bax ratio, induce upregulated expression of Caspase-3 and Caspase-6, and cause increase in the activities of Caspase-3, Caspase-6, and Caspase-9.

Animals ; Apoptosis ; drug effects ; Benzo(a)pyrene ; toxicity ; Caspases ; metabolism ; Hippocampus ; cytology ; drug effects ; Male ; Neurons ; drug effects ; metabolism ; pathology ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Rats ; Rats, Sprague-Dawley ; bcl-2-Associated X Protein ; metabolism