Aluminum-induced "mixed" cell death in mice cerebral tissue and potential intervention.

The brain is one of organs vulnerable to aluminum insult. Aluminum toxicity is involved in neurobehavioral deficit, neuronal cell dysfunction, and death. The aim of this study are as follows: (1) to evaluate the repairing efficiency of Necrostatin-1 (Nec-1), a cell death inhibitor, and Z-VAD-FMK, a pan-caspase inhibitor, on Al-induced neurobehavioral deficit and neuronal cell death, in order to evidence the cell death inducing ability of aluminum, and (2) to primarily explore the possibility of treating neuronal cell loss-related disease, such as Alzheimer's disease, with Nec-1 and Z-VAD in Al-induced dementia animal model. We found Nec-1 and Z-VAD-FMK alone or in combination could reduce aluminum-induced learning and memory impairment in mice. Pathohistological results indicated that Nec-1 and Z-VAD-FMK can decrease Al-induced neuronal death cell. In addition, some cell death-associated proteins in cell death signal pathway were inhibited by Nec-1 and Z-VAD-FMK in Al-exposed mice. In conclusions, Nec-1 and Z-VAD-FMK can repair the injury of learning and memory induced by aluminum in mice. Furthermore, Nec-1 was more obvious to repair the injury of learning and memory function compared with Z-VAD-FMK. Nec-1 and Z-VAD-FMK can repair the Al-induced morphological injury of cell and reduce the amounts of dead cell, and repairing effects were more significant at higher doses. The effect of Nec-1 was stronger than Z-VAD-FMK, though their mechanism was different. The combination of them had the strongest effect. Our study evidenced Al-induced neuronal necroptosis and apoptosis existing in animal model and suggested potential therapeutic effects of Nec-1 and Z-VAD-FMK on neuronal cell death in neurodegenerative diseases.

[Effect of necrostatin-1 on apoptosis induced by aluminum and its mechanism].

OBJECTIVE: To study the effect of necrostatin (Nec-1) on apoptosis induced by aluminum (Al), and approach the mechanism. METHODS: Neural cell death model was made by 4 mmol/L Al treated neuroblastoma cells (SH-SY5Y). Cell viabilities were detected at different concentrations of Al and/or Nec-1. Hoechst 33342/PI double staining was used to observe apoptosis and (or) necrosis that were quantified by flow cytometry using Annexin V/PI double staining. Apoptotic pathway was tested by activities of Caspase-3, Caspase-8 and Caspase-9. In addition, the expression of NF-kappa B and Cyt-c was measured by immunocytochemistry. RESULTS: Cell viabilities were significantly decreased with the increasing concentrations of Al (P < 0.05), which could be significantly upregulated by 60 micromol/L Nec-1 (P < 0.05) and were correlated with the concentrations of Nec-1 (P < 0.05, P < 0.01). Apoptosis and necrosis were observed under fluorescent microscope and quantified by flow cytometry, which suggested an increasing trend of apoptotic and necrotic rates (P < 0.05, P < 0.01). Whereas, Nec-1 could not only decrease the necrotic rate but also apoptotic rate as well (P < 0.05, P < 0.01). Data of Nec-1 on caspases activities showed that Nec-1 could not affect Caspase-9 activity (P > 0.05) and Cty-c protein expression as well (P > 0.05). However, Nec-1 could reduce Caspase-8 activity significantly (P < 0.05, P < 0.01) and increase NF-kappa B protein expression (P < 0.05, P < 0.01) and finally decrease Caspase-3 activity (P < 0.05). CONCLUSION: Nec-1 could reduce cell apoptosis induced by Al, through Caspase-8 pathway, and up-regulate the expression of NF-kappa B protein.

[Influence of benzo[a]pyrene on learning and memory and content of amino acid neurotransmitters in hippocampus of rats].

OBJECTIVE: To study the effects of benzo[a]pyrene (B[a]P) on capability of learning and memory and the content of amino acid neurotransmitters in hippocampus of rats. METHODS: Thirty-two healthy, male SD rats were randomly divided into 4 groups according to their weights after intubated into ventricles: the solvent control group, 2.5, 5.0 and 10.0 mmol/L groups. 10 microl of B[a]P olive oil solutions, of different concentrations 2.5, 5.0 and 10.0 mmol/L, were injected into rats' lateral ventricles, respectively. Rats in the solvent control group were injected into the same volume of olive oil as that in B[a]P group. Rats' capability of learning and memory was tested by Morris water maze. The content of amino acid neurotransmitters in rats' hippocampus were determined by high performance liquid chromatogram with a fluorescence detector. RESULTS: Compared with the controls, the performances of learning and memory of rats decreased significantly in B[a]P treated groups (P<0.01). Levels of glutamate (Glu) were lower significantly in treated groups than that in controls (P<0.01). No significant differences were found in contents of aspartic acid (Asp), glycine (Gly) and aminobutyric acid (GABA) among the four groups. CONCLUSION: B[a]P can damage rats' spatial learning and memory, and which could be related to decreased contents of excitatory amino acids in hippocampus.