[Influence of aluminum on microRNA29 and β-site amyloid precursor protein cleaving enzyme 1 in the brain of rats].

Objective: To investigate the influence of aluminum on microRNA29 (miR29) subtypes miR29a, miR29a*, miR29b1, miR29b2, miR29c1, and miR29c2 and β-site amyloid precursor protein cleaving enzyme 1 (BACE1) in the brain of rats. Methods: A total of 40 Sprague-Dawley rats were randomly divided into control group and 15, 30, and 45 μmol/kg groups according to the body weight, with 10 rats in each group. The rats were exposed to aluminum (at a dose of 0.1 ml/100 g body weight) by intraperitoneal injection for 8 weeks. The rats in control group were given 0.9% normal saline, and those in exposure groups were given aluminum-maltolate (equivalent volumesof maltolate and aluminum solution were mixed before exposure) . The cerebral cortex and hippocampus were isolated after exposure ended; Western blotting was used to measure the change in BACE1 expression, and real-time reverse transcription polymerase chain reaction was used to measure the mRNA expression of miR29 subtypes in the cerebral cortex and hippocampus. Results: Compared with the control group, the 45 μmol/kg group had a significant increase in BACE1 expression in the cerebral cortex, and the 30 and 45 μmol/kg groups had significant increases in BACE1 expression in the hippocampus (all P<0.05) . Compared with the control group, the 15, 30, and 45 μmol/kg groups had significant reductions in the mRNA expression of miR29a*, miR29b2, miR29c1, and miR29c2 in the cerebral cortex and hippocampus (all P<0.01) , and the 45 μmol/kg group had significant reductions in the mRNA expression of miR29a and miR29b1 in the cerebral cortex and hippocampus (all P<0.05) . The results of correlation analysis showed that there was no correlation between the mRNA expression of miR29a*, miR29b2, miR29c1, and miR29c2 and BACE1 expression in the cerebral cortex and hippocampus (all P>0.05) , while the mRNA expression of miR29a and miR29b1 was negatively correlated with BACE1 expression (cerebral cortex: r=-0.987 and -0.981, P<0.05; hippocampus: r=-0.992 and -0.991, P<0.05) . Conclusion: Aluminum can reduce the expression of miR29 subtypes and increase BACE1 expression in the brain, and the expression of miR29a and miR29b1 is negatively correlated with BACE1 expression.