Objective To investigate the effect of caspase-3 siRNA on apoptosis of neurons in mice induced by aluminum through observation of mitochondrial membrane potential, tissue morphology and protein expression level of activated caspase-3.
Methods Three-month-old male Kunming mice were divided into 4 groups randomly by weight:blank control group (normal saline 4 μL), emptyvector group (0.5% AlCl3& #183;6H2O 4 μL), aluminum exposed group (0.5% AlCl3& #183;6H2O 3 μL + the purpose of siRNA expression vector 1 μL)and Al+RNAi group (0.5% AlCl3& #183;6H2O 3 μL +control siRNA expression vector 1 μL). Every group was treated by lateral cerebral ventricle micro-injection for 5 days. The apoptosis rate of hippocampus cells was measured by fluorescent analysis, and mitochondrial membrane potential by Rhodaminer 123 (Rhl23)staining. The histological changes in mice were observed; the expression of activated caspase-3 in mice brain was detected by Western-blot.
Results The results of fluorescent analysis in the aluminum exposed group and the empty vector group were significantly higher than the blank control group (P<0.05), but the Al+RNAi group showed no change (P>0.05); light green mitochondria were found in Rhl23 staining. The mitochondrial membrane potentials in the aluminum group and empty vector group were lower than the blank control group(P<0.05), but there was no difference between the Al+RNAi group and the blank control group; the morphosis of mice hippocamp neuron of the blank control group were lining up in order in HE staining. The cell alignment became disrupted in the aluminium exposed group. Loose cell junctions were also found in the aluminum exposed group.The amount of cells in empty vector group decreased compared to the blank control group, but no difference was found after treated with siRNA. The caspase-3 expression level increased after aluminum exposed (P<0.05), but no siginificant changes in the empty vector group and the Al+RNAi group (P>0.05).
Conclusion RNA interference technology can turn down the expression of caspase-3 gene to inhibit apoptosis induced byaluminum in nerve cell of mice.
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