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 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

OBJECTIVETo study the effect of aluminum chloride on motor and species-typical behaviors in mice.

METHODSMale ICR mice were administered with drinking double distilled water only containing AlCl(3) (10, 50, 300 mg x kg(-1) x d(-1)), and control group with drinking double distilled water only for 100 days. Spontaneous activity test, grip strength, beam traversal, tightrope task, food hoarding, and nest construction were used to study the effect of chloride aluminum on motor and species-typical behaviors in mice.

RESULTSThe frequencies of spontaneous activity in low dose group, medium dose group and high dose group [(81.53 +/- 8.97), (71.67 +/- 8.37), (66.73 +/- 6.96) times respectively] were lower than that in control [(106.46 +/- 8.21) times] (P < 0.01), and were negatively correlated with doses (r(s) = -0.42, P < 0.01). Grip strength scores in medium dose group (19.19 +/- 1.48) and high dose group (13.36 +/- 1.46) respectively were lower than that in control (24.31 +/- 1.43) (P < 0.05, P < 0.01). Food hoarding was greater in high dose group [96.10 (90.20-99.00) g] than that in control group [84.00 (78.00-90.00) g (P < 0.05)]. The rest of parameters were of no statistical significance.

CONCLUSIONSubchronic exposure to AlCl(3) in mice may diminish motor activity and grip strength, but motor coordination was not impaired; alteration in food hoarding suggests damage to hippocampus cell.

Aluminum Compounds ; toxicity ; Animals ; Behavior, Animal ; drug effects ; Chlorides ; toxicity ; Dose-Response Relationship, Drug ; Male ; Mice ; Mice, Inbred ICR ; Motor Activity ; drug effects

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

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

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

The effects of aluminum chloride (AlCl3) on the transient outward potassium and delayed rectifier K(+) current in hippocampal CA1 neurons of rats were studied by the whole-cell patch clamp technique. It was found that AlCl3 reduced the transient outward potassium current and delayed rectifier K(+) current in a dose-dependent manner. 1000 micromol/L AlCl3 resulted in change in voltage and slope of the half-activation and the half-inactivation of I(A) and I(K). These results imply that AlCl3 may damage potassium channel of the hippocampal CA1 neurons from rats and this may be related to the mechanism of the damage to the central nervous system by aluminum.
Aluminum Compounds ; toxicity ; Animals ; CA1 Region, Hippocampal ; cytology ; Cell Separation ; Chlorides ; toxicity ; Delayed Rectifier Potassium Channels ; physiology ; Female ; Male ; Neurons ; drug effects ; physiology ; Patch-Clamp Techniques ; Rats ; Rats, Wistar ; Shal Potassium Channels ; physiology

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