OBJECTIVEIn this research, we have observed changes of PHF8、H3K9me2、BDNF, and their regulatory roles in changing the amplitude value of LTP in hippocampus due to aluminum exposure so that we can discuss the impact on the learning and memory that caused by chronic aluminum exposure.

METHODSForty healthy SPF grade SD male rats were randomly divided into four groups by weight, including control group and low, medium, high dose aluminum exposed group, each group had 10 rats. The exposed rats drank water containing different doses of aluminum chloride (AlCl3) (2、12、72 mg/kg Al(3+)) for 90 d. We measured LTP in hippocampus by electrophysiological grapier and detected the expression of PHF8、H3K9me2、BDNF by western-blot.

RESULTSElectrophysiological measurements shows that compared with that of control group, the average of fEPSPs was decreased at different time points in all exposed groups (P<0.01) . The results of western-bolt test demonstrated that the expression of PHF8 in the exposed groups were significantly lower than those of control group (P<0.01) . And the expression the of H3K9me2 of medium and high dose groups were significantly higher than control group (P<0.05) . While the expression of BDNF of medium and high dose groups were decreased compared with the control group (P<0.05) .

CONCLUSIONChronic aluminum exposure can reduce the LTP via the route of PHF8-H3K9me2-BDNF in the hippocampus of rats, which then may impair the ability of learning and memory.

Aluminum ; toxicity ; Aluminum Compounds ; toxicity ; Animals ; Brain-Derived Neurotrophic Factor ; metabolism ; Chlorides ; toxicity ; Hippocampus ; drug effects ; metabolism ; Histone Demethylases ; metabolism ; Learning ; drug effects ; Long-Term Potentiation ; drug effects ; Male ; Memory ; drug effects ; Pilot Projects ; Rats ; Rats, Sprague-Dawley ; Transcription Factors ; metabolism

OBJECTIVETo explore the role of P53 phosphorylation in neuron apoptosis of rats by chronic aluminum exposure.

METHODSA total of male 40 SD rats were divided randomly into 4 groups (n = 10/dose), the exposed groups were fed with normal diet with different concentration of AlCl3 · 6H2O for 6 months respectively. The dosage of low, middle and high groups were 10.73, 107.33, 1073.33 mg/kg in sequence. The control group received normal diet. The neuron apoptosis was measured by method of Tunel. The expressions of P53 and pP53-ser15 protein in the cortex were detected by Western-blot.

RESULTSTunel staining showed that the low, middle and high group rats had increased apoptosis rate than control group (P < 0.01). Western-blot test demonstrated that the expression of P53 protein in the cortex of high group rats were significantly higher than the control and low groups (P < 0.05). The expression of pP53-ser15 protein in the cortex of middle and high group rats were also higher than the control and low groups (P < 0.05).

CONCLUSIONChronic aluminum exposure can lead to over expression of P53 and pP53-ser15 protein in cerebral cortex, which maybe one of the most important mechanisms of neuron apoptosis induced by AlCl3.

Aluminum ; toxicity ; Aluminum Compounds ; toxicity ; Animals ; Apoptosis ; Cerebral Cortex ; metabolism ; Chlorides ; toxicity ; Male ; Neurons ; cytology ; drug effects ; Phosphorylation ; Rats ; Rats, Sprague-Dawley ; Tumor Suppressor Protein p53 ; metabolism

OBJECTIVETo investigate the effect of aluminum trichloride on the abnormal phosphorylation of tau protein in SH-SY5Y cells.

METHODSSH-SY5Y cells were assigned to control group and aluminum trichloride exposure groups (200, 400, and 800 µmol/L Al(3+)). The cell morphology was observed after 48 hours of exposure; the cell viability was measured by CCK-8 assay; total protein was extracted from the cells, and the expression of phospho-tau (p-tau) 181, 231, 262, and 396 and tau 5 was measured by Western blot.

RESULTSAs the Al(3+) concentration rose, the number of living SH-SY5Y cells decreased, and the synapses of the cells retracted. The viability of cells exposed to 800 µmol/L Al(3+) was significantly lower than that of the control group (P < 0.05). The 200, 400, and 800 µmol/L Al(3+) exposure groups showed significantly higher expression of p-tau 181, 231, and 396 and tau5 than the control group (P < 0.05), and the 800 µmol/L Al(3+) exposure group showed significantly higher expression of p-tau 262 than the control group (P < 0.05).

CONCLUSIONUnder the present experimental conditions, aluminum trichloride has toxic effect on SH-SY5Y cells and can lead to abnormal expression of p-tau 181, 231, and 396 and tau 5 at low Al(3+) concentration.

Aluminum Compounds ; toxicity ; Cell Line, Tumor ; Cell Survival ; drug effects ; Chlorides ; toxicity ; Humans ; Phosphorylation ; tau Proteins ; metabolism

OBJECTIVETo explore the effect of MnCl(2) on the mitochondrial function of human lung cells, and to study the changes of protein expression level of nuclear respiratory factor-1 (NRF-1) in mitochondrial dysfunction induced by MnCl(2).

METHODSThe effects of MnCl(2) on cell survival rate were assessed by the reductions of tetrazolium dye (MTT) in cultured cell lines 16HBE and A549 cells. All tested16HBE and A549 cells were incubated with different concentrations of MnCl(2). The permeability transition pore (PTP) of mitochondria, mitochondrial membrane potential and the inhibition rate of mitochondrial enzymes as indicators of mitochondrial damage were measured by fluorescent spectrometry and MTT assay, respectively. Apoptosis was determined by flow cytometry. Protein levels of NRF-1 and mtTFA were measured by Western blot assay.

RESULTSMnCl(2) decreased the survival rate of the two cell lines. The IC(50) of 16HBE and A549 cells were 1.91 mmol/L and 1.98 mmol/L, respectively. MnCl(2) caused a concentration-dependent decrease of mitochondrial enzymes and the inhibition rate of mitochondrial enzymes of the two cell lines induced by 1.00 mmol/L MnCl(2) were (52.8 ± 5.4)% and (50.6 ± 2.2)%, respectively. The PTP opening increased in MnCl(2)-treated cells in a dose- and time-dependent manner. Compared with the control group, mitochondrial membrane potential in the two cell lines was decreased by MnCl(2), by (7.9 ± 3.0)%, (26.2 ± 2.2)% and (27.8 ± 4.1)% in the 16HBE cells, and (4.7 ± 1.0)%, (14.9 ± 2.4)% and (27.5 ± 1.2)% in the A549 cells. Increased apoptosis rates of the two cell lines were induced by 1.00 mmol/L MnCl(2), (12.3 ± 1.9)% and (6.0 ± 0.4)%, respectively. The results of Western blot assay revealed that the protein levels of NRF-1 and mtTFA were decreased in manganese-treated cells in a dose-dependent manner, with a significant difference compared with that of the control cells (P < 0.05).

CONCLUSIONMnCl(2) induces mitochondrial dysfunction in 16HBE and A549 cells, and decreases the expression level of nuclear respiratory factor-1 (NRF-1), indicating that NRF-1 may play an important role in mitochondrial dysfunction.

Apoptosis ; drug effects ; Bronchi ; cytology ; Cell Line, Tumor ; Cell Survival ; drug effects ; Cells, Cultured ; Chlorides ; administration & dosage ; toxicity ; DNA-Binding Proteins ; metabolism ; Dose-Response Relationship, Drug ; Epithelial Cells ; cytology ; metabolism ; Humans ; Lung Neoplasms ; metabolism ; pathology ; Manganese Compounds ; administration & dosage ; Membrane Potential, Mitochondrial ; drug effects ; Mitochondria ; drug effects ; physiology ; Mitochondrial Membrane Transport Proteins ; drug effects ; Mitochondrial Proteins ; metabolism ; Nuclear Respiratory Factor 1 ; metabolism ; Transcription Factors ; metabolism

OBJECTIVES: Manganese chloride (MnCl2) is one of heavy metals for causing neurogenerative dysfunction like Manganism. The purpose of this study was to determine the acute toxicity of MnCl2 using different times and various concentrations including whether manganese toxicity may involve in two intrinsic pathways, endoplasmic reticulum (ER) stress and mitochondria dysfunction and lead to neuronal apoptosis mediated by organelle disorders in neuroblastoma cell line SK-N-MC. METHODS: In the acute toxicity test, five concentrations (200, 400, 600, 800, 1,000 uM) of MnCl2 with 3, 6, 12, 24, 48 hours exposure were selected to analyze cell viability. In addition, to better understand their toxicity, acute toxicity was examined with 1,000 uM MnCl2 for 24 hours exposure via reactive oxygen species (ROS), mitochondria membrane potential, western blotting and mitochondrial complex activities. RESULTS: Our results showed that both increments of dose and time prompt the increments in the number of dead cells. Cells treated by 1,000 microM MnCl2 activated 265% (+/-8.1) caspase-3 compared to control cell. MnCl2 induced intracellular ROS produced 168% (+/-2.3%) compared to that of the control cells and MnCl2 induced neurotoxicity significantly dissipated 48.9% of mitochondria membrane potential compared to the control cells. CONCLUSIONS: This study indicated that MnCl2 induced apoptosis via ER stress and mitochondria dysfunction. In addition, MnCl2 affected only complex I except complex II, III or IV activities.
Apoptosis ; Blotting, Western ; Caspase 3 ; Cell Line ; Cell Survival ; Chlorides ; Endoplasmic Reticulum ; Endoplasmic Reticulum Stress ; Manganese ; Manganese Compounds ; Membrane Potentials ; Metals, Heavy ; Mitochondria ; Neuroblastoma ; Neurons ; Organelles ; Reactive Oxygen Species ; Toxicity Tests, Acute

The present experiments were done to determine the effectiveness of a non-specific nitric oxide synthase inhibitor, N-nitro-L-arginine methyl ester (L-NAME), on oxidative stress parameters induced by aluminium chloride (AlCl3) intrahippocampal injections in Wistar rats. Animals were sacrificed 3 h and 30 d after treatments, heads were immediately frozen in liquid nitrogen and forebrain cortices were removed. Crude mitochondrial fraction preparations of forebrain cortices were used for the biochemical analyses: nitrite levels, superoxide production, malondialdehyde concentrations, superoxide dismutase (SOD) activities and reduced glutathione contents. AlCl3 injection resulted in increased nitrite concentrations, superoxide anion production, malondialdehyde concentrations and reduced glutathione contents in the forebrain cortex, suggesting that AlCl3 exposure promoted oxidative stress in this brain structure. The biochemical changes observed in neuronal tissues showed that aluminium acted as a pro-oxidant. However, the non-specific nitric oxide synthase (NOS) inhibitor, L-NAME, exerted anti-oxidant actions in AlCl3-treated animals. These results revealed that NO-mediated neurotoxicity due to intrahippocampal AlCl3 injection spread temporally and spatially to the forebrain cortex, and suggested a potentially neuroprotective effect for L-NAME.
Aluminum Compounds/*toxicity ; Animals ; Chlorides/*toxicity ; Glutathione/metabolism ; Male ; Malondialdehyde ; NG-Nitroarginine Methyl Ester/*pharmacology ; Nitric Oxide Synthase/*antagonists & inhibitors ; Nitrites/chemistry/metabolism ; Prosencephalon/*drug effects ; Rats ; Rats, Wistar ; Superoxide Dismutase/metabolism ; Superoxides/metabolism

BACKGROUNDIncreasing evidence suggests that many neurons may die through apoptosis in Alzheimer's disease (AD). Mitochondrial dysfunction has been implicated in this process of neuronal cell death. One promising approach for preventing AD is based upon anti-apoptosis to decrease death of nerve cells. In this study, we observed the memory improving properties of curcumin in mice and investigated the neuroprotective effect of curcumin in vitro and in vivo.

METHODSThe mice were given AlCl(3) orally and injections of D-galactose intraperitoneally for 90 days to establish the AD animal model. From day 45, the curcumin group was treated with curcumin for 45 days. Subsequently, the step-through test, neuropathological changes in the hippocampus and the expression of Bax and Bcl-2 were carried out to evaluate the effect of curcumin on the AD model mice. In cultured PC12 cells, AlCl(3) exposure induced apoptosis. The MTT assay was used to measure cell viabilities; flow cytometric analysis to survey the rate of cell apoptosis; DNA-binding fluorochrome Hoechst 33258 to observe nuclei changes in apoptotic cells and Western blot analysis of Bax, Bcl-2 to investigate the mechanisms by which curcumin protects cells from toxicity.

RESULTSCurcumin significantly improved the memory ability of AD mice in the step-through test, as indicated by the reduced number of step-through errors (P < 0.05) and prolonged step-through latency (P < 0.05). Curcumin also attenuated the neuropathological changes in the hippocampus and inhibited apoptosis accompanied by an increase in Bcl-2 level (P < 0.05), but the activity of Bax did not change (P > 0.05). AlCl(3) significantly reduced the viability of PC12 cells (P < 0.01). Curcumin increased cell viability in the presence of AlCl(3) (P < 0.01). The rate of apoptosis decreased significantly in the curcumin group (P < 0.05) when measured by flow cytometric analysis. Curcumin protected cells by increasing Bcl-2 level (P < 0.05), but the level of Bax did not change (P > 0.05).

CONCLUSIONSThis study demonstrates that curcumin improves the memory ability of AD mice and inhibits apoptosis in cultured PC12 cells induced by AlCl(3). Its mechanism may involve enhancing the level of Bcl-2.

Aluminum Compounds ; toxicity ; Alzheimer Disease ; drug therapy ; psychology ; Animals ; Apoptosis ; drug effects ; Cells, Cultured ; Chlorides ; toxicity ; Curcumin ; pharmacology ; therapeutic use ; Disease Models, Animal ; Female ; Learning ; drug effects ; Memory ; drug effects ; Mice ; Neuroprotective Agents ; pharmacology ; PC12 Cells ; Rats

OBJECTIVETo examine the protective effect of Ginkgo biloba leaf extract (GbE) on learning and memory deficit induced by aluminum chloride (AlCl(3)), and explore its mechanisms.

METHODSThe rat models with learning and memory deficit were induced by administering via gastrogavage and drinking of AlCl(3) solution. And the model rats were treated with GbE at the dose of 50, 100, 200 mg/kg every day for 2 months accompanied with drinking of AlCl(3) solution, respectively. Their abilities of spatial learning and memory were tested by Morris water maze, and the acetylcholinesterase (AChE) activity in serum was assayed with chemical method, the AChE expression in hippocampus was observed by immunohistochemistry assay, and then quantitative analysis was done by BI 2000 image analysis system.

RESULTSLearning and memory deficit of rats could be induced by AlCl(3) solution (P < 0.01), and AChE expressions in rats hippocampus were increased (P < 0.01); GbE ameliorated learning and memory deficit and reduced AChE expression in rats hippocampus in a dose-dependent manner, while GbE significantly increased serum AChE activity at the dose of 200 mg/kg each day (P < 0.05).

CONCLUSIONGbE can ameliorate learning and memory deficit induced by AlCl(3), which may be due to its inhibition of the AChE expression in hippocampus.

Acetylcholinesterase ; metabolism ; Aluminum Compounds ; toxicity ; Animals ; Chlorides ; toxicity ; Dose-Response Relationship, Drug ; Ginkgo biloba ; Hippocampus ; enzymology ; Immunohistochemistry ; Male ; Maze Learning ; drug effects ; Memory Disorders ; chemically induced ; prevention & control ; Neuroprotective Agents ; therapeutic use ; Phytotherapy ; Plant Extracts ; therapeutic use ; Plant Leaves ; Plant Structures ; Rats ; Rats, Wistar ; Reaction Time

Aluminum Compounds ; toxicity ; Animals ; Animals, Newborn ; Apoptosis ; drug effects ; Cells, Cultured ; Cerebral Cortex ; cytology ; drug effects ; Chlorides ; toxicity ; Dose-Response Relationship, Drug ; Neurons ; cytology ; drug effects ; Rats ; Rats, Wistar

OBJECTIVETo investigate the effect of aluminum chloride on dissociated Ca(2+) in hippocampus neuron cells in mice and the relationship to the learning and memory.

METHODSMale ICR mice in the three intoxicated groups were administered with the double distilled water containing AlCl(3) (10, 50, 300 mg.kg(-1).d(-1)) while those in the control group were administered with the double distilled water for 100 days. The methods of behavior toxicology such as Morris swim maze were used for studying the effect of aluminum chloride on the changes of learning and memory in mice. With calcium sensitive fluorescence indicator Fura-2 as the fluorescent probe, the influence of the subchronic exposure to Al on the dissociated Ca(2+) in hippocampus neuron cells was observed.

RESULTSThe dissociated Ca(2+) in hippocampus neuron cells in the middle dosage group and the high dosage group [(412.25 +/- 53.20), (467.37 +/- 32.85) times] was lower than those in the control group [(293.91 +/- 32.21) times] respectively (P < 0.01), and correlated positively with the dose and dissociated Ca(2+) (r = 0.861, P < 0.01). Compared with the control group, the latent period was lengthened (P < 0.05) in the middle dosage and the high dosage group.

CONCLUSIONThe subchronic exposure to AlCl(3) in mice affects the dissociated Ca(2+) in hippocampus neuron cells. The increase of dissociated Ca(2+) in hippocampus neuron cells may be correlated with the disfunction of cognition in the aluminium intoxicated mice.

Aluminum Compounds ; pharmacology ; toxicity ; Animals ; Calcium ; metabolism ; Chlorides ; pharmacology ; toxicity ; Dose-Response Relationship, Drug ; Hippocampus ; cytology ; drug effects ; metabolism ; Learning ; drug effects ; Male ; Memory ; drug effects ; Mice ; Mice, Inbred ICR ; Neurons ; metabolism