| ObjectiveAlzheimer’s disease(AD)is a neurodegenerative disease with a high incidence of middle-aged and elderly people.Inositol-requiring enzyme-1α(IRE1α)-microRNA(miRNA)signal abnormality is one of the pathological mechanisms of AD.MiR-200,miR-17,miR-34,miR-7 downstream of IRE1α can intervene in Aβ production and neuronal apoptosis and other pathological processes of AD.Exercise can prevent and alleviate AD,suggesting that the possible mechanism of exercise intervention in AD involves the regulation of IREIα-miRNA signals.In this study,3-month-old male APPswe/PS1 d E9(APP/PS1)transgenic mice and wild-type mice were selected as experimental subjects.To explore the effects of 12 weeks of moderate-intensity aerobic exercise on spatial learning and memory,Aβ and hippocampal cell apoptosis in APP/PS1 transgenic mice.From the perspective of IRE1α-miRNA signaling pathway,Preliminarily explore the possible mechanism of IRE1α-miRNA signaling pathway mediating exercise intervention in Aβ and neuronal apoptosis and other AD pathologies.MethodsEighteen 3-month-old male wild-type mice were randomly divided into wild-type sedentary control group(WTS)and wild-type exercise group(WTE).Eighteen 3-month-old male APP/PS1 transgenic mice were randomly divided into transgenic sedentary control group(ADS)and transgenic exercise group(ADE).Mice in WTE group and ADE group were given 12 weeks of moderate-intensity treadmill exercise intervention,45 minutes a day,5 days a week.The WTS group and ADS group were kept quietly.After the treadmill exercise,Morris water maze experiment was performed on mice in each experimental group.Test mice spatial learning and memory ability.24 hours after the completion of the water maze experiment,4 mice from each group were taken,and after anesthesia,the heart was perfused with paraformaldehyde,and the whole brain was taken to make paraffin sections for the TUNEL experiment to detect the apoptosis of the hippocampal tissues of the mice in each experimental group.Another 5 mice from each group were taken and sacrificed after anesthesia,and bilateral hippocampus were taken,and the contents of Aβ40 and Aβ42 in the hippocampus of each experimental group were detected by ELISA.WB and simple western experiments were used to detect the expression levels of GRP78,pIRE1α/IRE1α,XBP-1s,Caspase3,Bcl-2 and Bax in the hippocampus of each experimental group.PCR was used to detect the expression levels of miR-7,miR-17,miR-125,miR-34 a,miR-200 in the hippocampus of each experimental group.Results(1)Exercise can improve the spatial learning and memory ability of APP/PS1 mice:In the navigation test,compared with the WTS group,the escape latency of the ADS group was significantly increased on the 3rd(P <0.05),4(P <0.01),and 5(P<0.01)days;compared with the ADS group,the escape latency on the 4th(P <0.01)and 5(P<0.01)days in the ADE group was significantly reduced.Compared with the WTS group,the percentage of platform quadrant time on day 4th(P <0.05),5(P <0.05)in the ADS group significantly reduced;compared with the ADS group,the percentage of platform quadrant time on day 4(P <0.05)in the ADE group increased significantly.In the probe test,compared with WTS mice,the platform crossing times were significantly reduced in ADE mice(P < 0.01);compared with the ADS group,the platform crossing times of ADE mice were significantly increased(P < 0.05).Compared with the WTS group,the percentage of platform quadrant time in the ADS group increased significantly(P <0.05).(2)Exercise can reduce the expression of Aβ40 and Aβ42 in the hippocampus of APP/PS1 mice: ELISA results showed that compared with the WTS group,the expression of Aβ40 and Aβ42 in the hippocampus of the ADS group increased significantly(P <0.01).Compared with the ADS group,the expression levels of Aβ40and Aβ42 in the hippocampus of the ADE group were significantly reduced(P <0.01).(3)Exercise can reduce the apoptosis level of hippocampal nerve cells in APP/PS1mice: WB results show that,compared with the WTS group,the expression level of Caspase3(P <0.05)and the expression of Bax(P <0.01)in the hippocampus of the ADS group The level,Bax/Bcl2(P <0.01)ratio increased significantly.Compared with the ADS group,the expression level of Caspase3(P <0.01),the expression level of Bax(P <0.01),and the ratio of Bax/Bcl2(P <0.01)in the hippocampus of the ADE group were significantly reduced.The TUNEL results showed that compared with the WTS group,the number of TUNEL-positive cells in the hippocampus of the ADS group increased significantly(P <0.01).Compared with the ADS group,the number of TUNEL positive cells in the hippocampus of the ADE group was significantly reduced(P <0.01).(4)Exercise can alleviate the excessive activation of IRE1α in the hippocampus of APP/PS1 mice: WB results showed that the expression levels of GRP78(P <0.01)and XBP1s(P <0.01)in the hippocampus of the ADS group were significant compared with the WTS group.Increase,the ratio of IRE1α/p-IRE1α(P <0.05)increased significantly.Compared with the ADS group,the expression level of GRP 78(P <0.05),the expression level of XBP1s(P <0.01),and the ratio of IRE1α/p-IRE1α(P <0.01)in the hippocampus of the ADE group were significantly reduced.(5)Exercise can regulate the expression level of miRNA in the hippocampus of APP/PS1 mice: PCR results showed that compared with the WTS group,miR-34a(P<0.01)and miR-200a(P <0.01)in the hippocampus of the ADS group The expression level of miR-200c(P <0.05)decreased significantly.Compared with the ADS group,miR-7b(P <0.05),miR-96a(P <0.05),miR-34a(P <0.05),miR-200a(P <0.05),miRThe expression levels of 125a(P <0.01),miR-34b(P <0.01),and miR-34c(P <0.01)increased significantly.ConclusionsThis study found that 6-month-old APP/PS1 transgenic mice have decreased learning and memory ability,and increased hippocampal Aβ and neuronal apoptosis levels.This process is related to the imbalance of IRR1α stress in hippocampus and the abnormal expression of downstream miRNAs.exercise can improve AD by regulating the IRE1α-miRNA signaling pathway.The specific mechanism may be that exercise can relieve the excessive activation of IRE1α,regulate the expression of downstream miRNAs of IRE1α,inhibit Aβ aggregation and neuronal apoptosis,and thereby improve the spatial learning and memory ability of AD mice. |
PDF Full Text Request