PURPOSE: To investigate the effects of hyperbaric oxygen (HBO) pretreatment on cognitive decline and neuronal damage in an Alzheimer’s disease (AD) rat model. MATERIALS AND METHODS: Rats were divided into three groups: normal saline (NS), AD, and HBO+AD. In the AD group, amyloid β peptide (Aβ)₁₋₄₀ was injected into the hippocampal CA1 region of the brain. NS rats received NS injection. In the HBO+AD group, rats received 5 days of daily HBO therapy following Aβ₁₋₄₀ injection. Learning and memory capabilities were examined using the Morris water maze task. Neuronal damage and astrocyte activation were evaluated by hematoxylin-eosin staining and immunohistochemistry, respectively. Dendritic spine density was determined by Golgi-Cox staining. Tumor necrosis factor-α, interleukin-1β, and interleukin-10 production was assessed by enzyme-linked immunosorbent assay. Neuron apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling. Protein expression was examined by western blotting. RESULTS: Learning and memory dysfunction was ameliorated in the HBO+AD group, as shown by significantly lower swimming distances and escape latency, compared to the AD group. Lower rates of neuronal damage, astrocyte activation, dendritic spine loss, and hippocampal neuron apoptosis were seen in the HBO+AD than in the AD group. A lower rate of hippocampal p38 mitogen-activated protein kinase (MAPK) phosphorylation was observed in the HBO+AD than in the AD group. CONCLUSION: HBO pretreatment improves cognition and reduces hippocampal damage via p38 MAPK in AD rats.
Alzheimer Disease/*therapy ; Amyloid beta-Peptides/*administration & dosage ; Animals ; Apoptosis ; *Cognition/drug effects ; Disease Models, Animal ; Enzyme-Linked Immunosorbent Assay ; Hippocampus/*enzymology ; *Hyperbaric Oxygenation ; In Situ Nick-End Labeling ; Interleukin-10/biosynthesis ; Interleukin-1beta/biosynthesis ; Learning/drug effects ; Male ; Memory/drug effects ; Neurons ; Peptide Fragments/*administration & dosage ; Rats ; Rats, Sprague-Dawley ; Sodium Chloride/administration & dosage ; Tumor Necrosis Factor-alpha/biosynthesis ; p38 Mitogen-Activated Protein Kinases/*metabolism

OBJECTIVETo observe the effects of polydatin on learning and memory and cyclin-dependent kinase 5 (Cdk5) kinase activity in the hippocampus of rats with chronic alcoholism.

METHODSForty rats were randomly divided into 4 groups: control group, chronic alcoholism group, low and high polydatin group. The rat chronic alcoholism model was established by ethanol 3.0 g/(kg · d) (intragastric administration). The abstinence scoring was used to evaluate the rats withdrawal symptoms; cognitive function was measured by Morris water maze experiment; Cdk5 protein expression in the hippocampus was detected by immunofluorescence; Cdk5 kinase activity in the hippocampus was detected by liquid scintillation counting method.

RESULTSThe abstinence score, escape latency, Cdk5 kinase activity in chronic alcoholism group rats were significantly higher than those of control group (P < 0.05). The abstinence score, escape latency in high polydatin group rats were significantly lower than those of chronic alcoholism group (P < 0.05); Cdk5 kinase activity in high and low polydatin group rats was significantly lower than that of chronic alcoholism group( P < 0.05); immunofluorescence showed that the Cdk5 positive cells of chronic alcoholism group were significantly increased compared with control group (P < 0.05), and the Cdk5 positive cells of polydatin groups were significantly decreased compared with chronic alcoholism group ( P < 0.05).

CONCLUSIONPolydatin-reduced the chronic alcoholism damage may interrelate with regulation of Cdk5 kinase activity.

Alcoholism ; physiopathology ; Animals ; Cyclin-Dependent Kinase 5 ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Glucosides ; pharmacology ; Hippocampus ; drug effects ; enzymology ; Learning ; drug effects ; Memory ; drug effects ; Rats ; Stilbenes ; pharmacology

OBJECTIVETo study the toxicity of methomyl to acetylcholinesterase (AChE) in different regions.

METHODSThe optimal temperature and time for measurement of AChE activity were determined in vitro. The dose- and time-response relationships of methomyl with AChE activity in human erythrocyte membrane, rat erythrocyte membrane, cortical synapses, cerebellar synapses, hippocampal synapses, and striatal synapses were evaluated. The half maximal inhibitory concentration (IC50) and bimolecular rate constant (K) of methomyl for AChE activity in different regions were calculated, and the type of inhibition of AChE activity by methomyl was determined.

RESULTSAChE achieved the maximum activity at 370 °C, and the optimal time to determine initial reaction velocity was 0-17 min. There were dose- and time-response relationships between methomyl and AChE activity in the erythrocyte membrane and various brain areas. The IC50 value of methomyl for AChE activity in human erythrocyte membrane was higher than that in rat erythrocyte membrane, while the Ki value of methomyl for AChE activity in rat erythrocyte membrane was higher than that in human erythrocyte membrane. Among synapses in various brain areas, the striatum had the highest IC50 value, followed by the cerebellum, cerebral cortex, and hippocampus, while the cerebral cortex had the highest Ki value, followed by the hippocampus, striatum, and cerebellum. Lineweaver-Burk diagram demonstrated that with increasing concentration of methomyl, the maximum reaction velocity (Vmax) of AChE decreased, and the Michaelis constant (Km) remained the same.

CONCLUSIONMethomyl is a reversible non-competitive inhibitor of AChE. AChE of rat erythrocyte membrane is more sensitive to methomyl than that of human erythrocyte membrane; the cerebral cortical synapses have the most sensitive AChE to methomyl among synapses in various brain areas.

Acetylcholinesterase ; metabolism ; Animals ; Cerebellum ; drug effects ; Cerebral Cortex ; drug effects ; Erythrocyte Membrane ; drug effects ; enzymology ; Hippocampus ; drug effects ; Humans ; Inhibitory Concentration 50 ; Methomyl ; toxicity ; Rats ; Synapses ; drug effects ; Toxicity Tests

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 Tongluo Xingnao effervescent tablets on learning and memory capacity and expression of Na(+)-K(+)-ATPase in hippocampus of rats with chronic cerebral ischemia-induced learning and memory dysfunction model.

METHODThe 2-VO method was used to establish sd rat model learning and memory dysfunction induced by chronic cerebral ischemia. The 50 rats in the successfully established model were randomly divided into the model control group, the Dihydroergotoxine Mesylate tablets group (0.7 mg x kg(-1), Tongluo Xingnao effervescent tablets high dose (7.56 g x kg(-1)), middle dose (3.78 g x kg(-1)) and low dose (1.59 g x kg(-1)) groups and the sham operation group (n = 10) as the control group. The groups were orally given 10 ml x kg(-1) x d(-1) drugs for consecutively 90 days. On the 86th day, Morris water maze was adopted for them. On the 90th day, a leaning and memory capacity test was held. The brain tissues were fixed with 10% formaldehyde and observed for pathomorphism after routine slide preparation and staining. The expression of hippocampal Na(+)-K(+)-ATPase was detected with immunohistochemistry and image quantitative analysis.

RESULTCompared with the model group, all of Tongluo Xingnao effervescent tablets groups showed significant decrease in the escape latency at the 5th day in the Morris water maze, and notable increase in the frequency of the first quadrant dwell, the frequency passing the escape platform and the frequency entering effective area (p < 0.05). According to the pathomorphological detection, the control group showed a significantly higher pathological score than the sham operation group (p < 0.01), the middle dose group showed a significantly lower pathological score than the model group (p < 0.05). According to the immunohistochemistical detection, the model control group showed a remarkably lower mean OD value of Na(+)-K(+)-ATPase than the sham operation group (p < 0.05), high and middle dose groups showed a significantly higher mean od value than the model control group (p < 0.01).

CONCLUSIONTongluo Xingnao effervescent tablets can improve the learning and memory capacity, reduce pathological changes of hippocampal tissues of rats with chronic cerebral ischemia-induced learning and memory dysfunction model, and promote the expression of Na(+)-K(+)-ATPase in hippocampus.

Animals ; Brain Ischemia ; drug therapy ; enzymology ; genetics ; psychology ; Chronic Disease ; drug therapy ; psychology ; Drugs, Chinese Herbal ; administration & dosage ; Female ; Hippocampus ; drug effects ; enzymology ; Humans ; Learning ; drug effects ; Male ; Memory ; drug effects ; Rats ; Rats, Sprague-Dawley ; Sodium-Potassium-Exchanging ATPase ; genetics ; metabolism ; Tablets ; administration & dosage

OBJECTIVETo investigate the protective effects of oxysophoridine (OSR) on primary cultured hippocampus neurons subjected to anoxia injury in neonatal rats and its mechanism.

METHODThe model of anoxia injury of hippocampus neurons in neonatal rats were primarily cultured in vitro by physical oxygen deficiency using glucose-free culture fluid. The survival rate of neurons, the leaking rate of lactate dehydrogenase (LDH), the intracellular contents of malondialdehyde (MDA) and nitric oxide (NO), the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) and nitric oxide synthase (NOS) were measured. The intracellular free calcium concentration ([Ca2+]i) in hippocampus neurons were detected with Ca(2+)-sensitive dual wavelength fluorescence spectrophotometer.

RESULTNeuron death occurred in the anoxia injury model group with increase of LDH leaking rate, the contents of NO, MDA, intracellular [Ca2+] and the elevated activity of NOS while decreased activities of SOD and GSH-PX. The hippocampus neurons subjected to anoxia injury were alleviated in OSR (0.625, 5, 10 microg x L(-1)) group.

CONCLUSIONOSR has significant protective effects on hippocampus neurons subjected to anoxic injury. The mechanism of its protective effect may relate to its reduction of calcium overload and against oxidation injury.

Alkaloids ; administration & dosage ; Animals ; Cells, Cultured ; Drugs, Chinese Herbal ; administration & dosage ; Female ; Glutathione Peroxidase ; metabolism ; Hippocampus ; cytology ; drug effects ; enzymology ; metabolism ; Humans ; Hypoxia ; drug therapy ; enzymology ; metabolism ; prevention & control ; Malondialdehyde ; metabolism ; Neurons ; cytology ; drug effects ; enzymology ; metabolism ; Nitric Oxide Synthase ; metabolism ; Protective Agents ; administration & dosage ; Rats ; Rats, Sprague-Dawley ; Sophora ; chemistry ; Superoxide Dismutase ; metabolism

OBJECTIVETo observe the effect of Huannao Yicong Prescription (, HNYC, a Chinese medical compound) extract on β-amyloid precursor protein (APP) metabolic signal transduction related protein kinase C (PKC), tyrosine amyloid protein kinase (TrKA), and glycogen synthase kinase-3 (GSK-3) in brain tissue of transgenic mouse dementia model induced by APP.

METHODSSixty dementia model transgenic 3-month-old mice induced by APP695V717I were randomly allocated in four groups: the model group (A), the Donepezil (0.65×10(-3) g·kg(-1)·(-1))-treated group (B), and the two HNYC-treated groups (C and D) with high dosage (2.8 g·kg(-1)·(-1)) and low dosage (1.4 g·kg(-1)·(-1)) of HNYC extract, respectively, 15 mice in each group. Besides, a normal control group was set up with 15 C57BL/6J mice with the same age and genetic background as the model mice. The drugs for treatment were administered once a day by dissolving in equal-volume distilled water through gastric infusion, continued for 6 months, to mice in group A and to normal control group equal-volume distilled water was administered instead. Spatial learning and memory capacity of mice were observed by Morris water maze; their one-time escape response memory capacity was tested by diving platform; and changes of PKC, TrkA, and GSK-3 levels in hippocampus and cortex of brain were detected by Western blotting.

RESULTSHNYC extract showed significant effects on increasing the time of model mice for swimming through the flat roof and the swimming time and path in the fourth quadrant P<0.05 or P<0.01). Diving platform test showed that the latent times in Groups B and C were longer than that in Group A significantly (P <0.05 and P<0.01). Compared with the normal control group, PKC and TrkA protein expression levels in hippocampus and cortex of model mice's brain lowered significantly (P<0.01), while GSK-3 protein expression increased significantly (P<0.01); compared with Group A (the model group), hippocampal and cortical levels of PKC protein expression in the intervened groups (B-D) as well as those of TrkA in Group C were higher (P<0.01 or P<0.05), while hippocampal levels of GSK-3 in intervened groups were lower (P<0.01).

CONCLUSIONHNYC extract could obviously increase the protein expressions of PKC and TrkA and decrease the expression of GSK-3 protein in brain tissue of transgenetic mice model of dementia, and regulate APP metabolic signal transduction path, and thus to suppress the production of Aβ, which is one of the dominant mechanisms for improving learning/memory capacity of dementia model animals.

Amyloid beta-Protein Precursor ; metabolism ; Animals ; Brain ; drug effects ; enzymology ; metabolism ; pathology ; Chromatography, High Pressure Liquid ; Dementia ; metabolism ; pathology ; Disease Models, Animal ; Drugs, Chinese Herbal ; pharmacology ; Female ; Glycogen Synthase Kinase 3 ; metabolism ; Hippocampus ; drug effects ; metabolism ; pathology ; Male ; Memory ; drug effects ; Mice ; Mice, Inbred C57BL ; Mice, Transgenic ; Plant Extracts ; pharmacology ; Protein Kinase C ; metabolism ; Receptor, trkA ; metabolism ; Signal Transduction ; drug effects

OBJECTIVETo study the effects of 1-bromopropane (1-BP) on the functions of learning-memory and the central cholinergic system in rats.

METHODSForty male Wistar rats were randomly divided into four groups: low 1-BP group (200 mg/kg), middle 1-BP group (400 mg/kg), high 1-BP group (800 mg/kg) and control group, and the exposure time was 7 days. The Morris water maze (MWM) test was applied to evaluate the learning-memory function in rats. After the MWM test, the rats were sacrificed, the cerebral cortex and hippocampus were quickly dissected and homogenized in ice bath. The activity of acetylcholine esterase (AChE) and choline acetyltransferase (ChAT) in supernatant of homogenate were detected.

RESULTSThe latency and swim path-length of rats in middle and high 1-BP groups prolonged significantly in place navigation test and the efficiency of searching strategy obviously decreased, as compared with control group (P < 0.05 or P < 0.01). In spatial probe test, the number of crossing platform in three 1-BP groups decreased significantly, as compared with control group (P < 0.05 or P < 0.01). The cortical AChE activity of rats in middle and high 1-BP groups was significantly higher than that of control and low 1-BP group (P < 0.05 or P < 0.01). The AChE activity in rat hippocampus of high 1-BP group obviously increased, as compared with control group as compared with control group (P < 0.05). There was no significant difference of cortical ChAT activity between three 1-BP groups and control group (P > 0.05). In the hippocampus, there was no difference of ChAT activity among the groups (P > 0.05).

CONCLUSION1-BP exposure could significantly influence the learning-memory function in rats due to the increase of AChE activity.

Acetylcholinesterase ; metabolism ; Animals ; Cerebral Cortex ; drug effects ; enzymology ; Choline O-Acetyltransferase ; metabolism ; Hippocampus ; drug effects ; enzymology ; Hydrocarbons, Brominated ; toxicity ; Male ; Maze Learning ; drug effects ; Rats ; Rats, Wistar

OBJECTIVETo observe the effect of a Chinese medicine compound, Naoerkang (NEK), on amyloid-beta peptide (1-42; Aβ(1-42)) and matrix metalloproteinase-9 (MMP-9) expressions in the hippocampus of Alzheimer's disease (AD) model rats.

METHODSA total of 48 male Sprague Dawley (SD) rats were randomly divided into normal control, untreated, and piracetam groups, and low-dose, medium-dose, and high-dose NEK groups, with 8 rats in each group. The 5-μL aggregated Aβ(1-42) (2 μg/μL) were injected into both CA1 areas of the hippocampus in the rats to establish an AD model, whereas the normal control was treated with the same dose of normal saline. The rats in the NEK groups were treated with a high, medium, or low dose of NEK [60 g/(kg·d), 30 g/(kg·d), and 15 g/(kg·d)], respectively, intragastrically for 28 days; piracetam (0.375 g/kg, intragastrically) was consecutively administered in the piracetam group; and normal saline was applied in the normal control and untreated groups. A Y-maze test was used for behavioral study to test the learning and memory abilities. Aβ(1-42) and MMP-9 expressions in the hippocampus was determined immunohistochemically, and the results were analyzed by image acquisition and an analysis system.

RESULTSAggregated Aβ(1-42) induced obvious learning and memory dysfunction, as well as up-regulation of Aβ(1-42) expression in the hippocampus. Compared with those in the normal control group, the learning and memory abilities of rats in the untreated group significantly decreased (P<0.01), and the expression of Aβ(1-42) was significantly increased (P<0.01). Twenty-eight days after different treatments, compared with those in the untreated group, the learning and memory abilities of AD model rats in the piracetam, low-dose, medium-dose and high-dose NEK groups were significantly improved (P<0.01 or P<0.05), and the expression of Aβ(1-42) in the hippocampus decreased (P<0.01 or P<0.05), and MMP-9 increased (P<0.01 or P<0.05), especially in the high-dose NEK group.

CONCLUSIONNEK might play a role of anti-dementia by increasing the expression of MMP-9 in the hippocampus of AD model rats, resulting in the reduction of the quantity of Aβ(1-42) and improvement in learning and memory ability in AD model rats.

Alzheimer Disease ; drug therapy ; metabolism ; pathology ; physiopathology ; Amyloid beta-Peptides ; metabolism ; Animals ; CA1 Region, Hippocampal ; drug effects ; enzymology ; pathology ; physiopathology ; Disease Models, Animal ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Hippocampus ; drug effects ; metabolism ; pathology ; physiopathology ; Immunohistochemistry ; Male ; Matrix Metalloproteinase 9 ; metabolism ; Memory ; drug effects ; Rats ; Rats, Sprague-Dawley

This in vitro study evaluated the detrimental effect of acute gamma (gamma)-irradiation on rat immature hippocampal neurons. Rat immature hippocampal neurons (0.5 day in vitro) were irradiated with 0~4 Gy gamma-rays. Cytotoxicity was analyzed using a lactate dehydrogenase release assay at 24 h after gamma-irradiation. Radiation-induced cytotoxicity in immature hippocampal neurons increased in a dose-dependent manner. Pre-treatments of pro-apoptotic caspase inhibitors and anti-oxidative substances significantly blocked gamma-irradiation-induced cytotoxicity in immature hippocampal neurons. The results suggest that the caspase-dependent cytotoxicity of gamma-rays in immature hippocampal cultured neurons may be caused by oxidative stress.
Amifostine/pharmacology ; Animals ; Antioxidants/pharmacology ; Caspase 3/metabolism/radiation effects ; Catechin/analogs & derivatives/pharmacology ; Cell Survival/radiation effects ; Cells, Cultured/cytology/enzymology/*radiation effects ; Dose-Response Relationship, Radiation ; Female ; *Gamma Rays ; Hippocampus/cytology/enzymology/*radiation effects ; L-Lactate Dehydrogenase/radiation effects ; Neurons/cytology/enzymology/*radiation effects ; Poly(ADP-ribose) Polymerases/drug effects ; Pregnancy ; Rats ; Rats, Sprague-Dawley