Mechanism Of CiRS-7 On Aluminum-induced Aβ Deposition

Objective:To observe the effect of aluminum exposure on the relevant indexes of ciRS-7pathway in the brain of rats through animal experiments,and clarify the effect of ciRS-7on aluminum induced AβThe action mechanism in deposition is aluminum induced AβThe study of sedimentary mechanism provides new ideas.Methods:1.Forty healthy male SD（Sprague Dawley）rats were randomly divided into control group and Al（mal）₃10μmol/kg group,Al（mal）₃20μmol/kg group,Al（mal）₃40μmol/kg group,10 rats in each group were injected intraperitoneally for two months.The content of aluminum in rat brain was detected by inductively coupled plasma mass spectrometry（ICP-MS）;The relative expression of ciRS-7 and miR-7 in hippocampus was detected by RT-q PCR;The expression of UBE2A in hippocampus was detected by Western blot;The expression of Aβ1-42 in hippocampus was detected by ELISA.2.The research object is pheochromocytoma-derived cell（PC12 cells）.The plasmid with the whole ciRS-7 gene was transferred into the cells using Lipo2000 to construct the transient model of ciRS-7 overexpression plasmid.The cells are divided into control group,100μmol/L Al（mal）₃group,200μmol/L Al（mal）₃group,400μmol/L Al（mal）₃group,plasmid empty group（NC group）,ciRS-7 overexpression group and ciRS-7overexpression+200μmol/L Al（mal）₃group.After 24 hours,the morphological changes of cells in each group were observed by electron microscope;The change of cell viability was detected by CCK-8;The relative expression of ciRS-7 and miR-7 was detected by RT-q PCR;The expression of UBE2A was detected by Western blot;The expression of Aβ1-42 was detected by ELISA.Results:1.Animal experiment results:Basic conditions of rats:No death of rats occurred during the whole experiment.The rats in the control group and Al（mal）₃10μmol/kg group had normal diet and activities,good hair color,active and lively,and Al（mal）₃20μmol/kg group,Al（mal）₃40μmol/kg group showed decreased activity,poor hair color and poor spirit.Brain aluminum contentin in hippocampus:Compared with the control group,the aluminum content in brain of rats in Al（mal）₃10μmol/kg group,Al（mal）₃20μmol/kg group and Al（mal）₃40μmol/kg group increased（P<0.05）.Relative expression of ciRS-7 and miR-7 in hippocampus:Compared with the control group,the relative expression of ciRS-7 in Al（mal）₃10μmol/kg group,Al（mal）₃20μmol/kg group and Al（mal）₃40μmol/kg group was decreased（P<0.05）;Compared with the control group,the relative expression of miR-7 in Al（mal）₃20μmol/kg group and Al（mal）₃40μmol/kg group was increased（P<0.05）.UBE2A expression in hippocampus:Compared with the control group,UBE2A expression in Al（mal）₃20μmol/kg group and Al（mal）₃40μmol/kg group was decreased（P<0.05）.Aβ1-42 expressionin in hippocampus:Compared with control group,Aβ1-42expression in Al（mal）₃20μmol/kg group and Al（mal）₃40μmol/kg group was increased（P<0.05）.2.Cell test results:Basic information of cells:With the increase of exposure dose,the number of cells in each dose group was gradually decreased.Compared with the control group,the morphology of cells in the exposure group was changed,the number of intercellular connections was decreased,some cell bodies were rounded,and the number of axons was decreased.There was no significant change in the NC group.And Compared with the200μmol/L Al（mal）₃group,the cellular damage in ciRS-7 overexpression+200μmol/L Al（mal）₃group was decreased,while the cell connections and the number of axons was increased.The relative expression of ciRS-7 and miR-7:Compared with the control group,200μmol/L Al（mal）₃group,400μmol/L Al（mal）₃group,the expression of ciRS-7 was decreased（P<0.05）and the expression of miR-7 was increased（P<0.05）.The expression of ciRS-7 and miR-7 was did not changed significantly in the 100μmol/L Al（mal）₃group（P>0.05）.And Compared with the 200μmol/L Al（mal）₃group,the expression of ciRS-7in ciRS-7 overexpression+200μmol/L Al（mal）₃group was increased（P<0.05）,while the expression of miR-7 was decreased（P<0.05）.UBE2A expression:Compared with the control group,the expression of UBE2A in400μmol/L Al（mal）₃group was decreased（P<0.05）.The UBE2A expression in the ciRS-7 overexpression+200μmol/L Al（mal）₃group was higher than 200μmol/L Al（mal）₃group（P<0.05）.Aβ1-42 expression:Compared with the control group,the expression of Aβ1-42 in400μmol/L Al（mal）₃group was increased（P<0.05）.The Aβ1-42 expression in the ciRS-7overexpression+200μmol/L Al（mal）₃group was lower than 200μmol/L Al（mal）₃group（P<0.05）.Conclusions:1.Aluminum maltol can cause the down-regulation of ciRS-7 expression,the increase of miR-7 expression,the down-regulation of UBE2A expression,and AβDeposition.2.The decreased expression of ciRS-7,which leads to the increase of miR-7expression and the down-regulation of UBE2A expression,is ultimately leading to Aβdeposition.