Effects Of Treadmill Exercise On AQP4 In Hippocampus Of APP/PS1 Transgenic AD Mice

Research Objectives:Aquaporin4（AQP4）plays an important role in the clearance of Amyloid-β（Aβ）in the brain of Alzheimer’s disease（AD）,and its abnormal function is one of the important causes of the onset of AD.In this study,18 13-week-old male APPswe/PS1 d E9（APP/PS1）transgenic mice and 18 13-week-old littermate male C57BL/6 mice were used as research objects to explore the effects of 12 weeks moderate intensity treadmill exercise on the expression of Aβ and the expression of AQP4 in the brain of AD mice,and to further explore the biological mechanism of the effect of exercise on the expression and localization of AQP4.Research Methods:APP/PS1 mice were randomly divided into AD Control group（ADC）and AD exercise group（ADE）,with 9 mice in each group.Wild-type mice were randomly divided into wild-type Control group（WTC）and wild-type exercise group（WTE）,with9 mice in each group.WTE group and ADE group received moderate intensity treadmill exercise for 12 weeks from the age of 13 weeks.Exercise program: five times a week,each 45 minutes.Morris water maze was used to measure spatial learning and memory of mice after 12 weeks of treadmill exercise.12 hours after the behavioral experiment,the mice were anesthetized with isoflurane and bilateral hippocampi were taken.The deposition of Aβ in the hippocampus of mice was detected by immunofluorescence assay;Western blotting assay was used to detect the protein expression of AQP4、SNTA1 and β-DG in the hippocampus of mice;The m RNA expressions of AQP4、SNTA1、β-DG、IL-1β、IL-6、TNF-α and MMP-9 in the hippocampus of mice were detected by real-time PCR;The co-localization levels of AQP4 and β-DG in the hippocampus of mice were detected by immunofluorescence double-label assay.Research Results:（1）In the positioning navigation experiment,compared with the WTC group,the escape latencye of ADC group was significantly prolonged（P<0.05）and the percentage of platform quadrant time was significantly decreased（P<0.05）from day 3;After 12 weeks treadmill exercise,compared with ADC group,the escape latency of ADE group was significantly shortened（P<0.05）and the percentage of platform quadrant time was significantly increased（P<0.05）from day 4.In space exploration experiment,compared with WTC group,the times of platform crossing in ADC group was significantly reduced（P<0.01）;After 12 weeks treadmill exercise,the times of platform crossing in ADE group was significantly increased compared with that in ADC group（P<0.05）.（2）Compared with WTC group,the mean intensity of Aβ in the hippocampus of ADC group was significantly increased（P<0.01）;Compared with ADC group,the mean intensity of Aβ in the hippocampus of ADE group was significantly decreased（P<0.05）.（3）Compared with WTC group,the m RNA level（P<0.01）、protein level（P<0.05）and mean intensity（P<0.01）of AQP4 in hippocampus of ADC group were significantly increased;Compared with ADC group,the m RNA level、protein level and mean intensity of AQP4 in the hippocampus of ADE group were significantly decreased（P<0.01）.（4）Compared with WTC group,the m RNA and protein levels of SNTA1 in hippocampus of ADC group were significantly decreased（P<0.05）;Compared with ADC group,the m RNA and protein levels of SNTA1 in the hippocampus of ADE group were significantly increased（P<0.05）.Compared with WTC group,the m RNA level（P<0.01）and protein level（P<0.05）of β-DG in hippocampus of ADC group were significantly decreased;Compared with ADC group,the m RNA and protein levels ofβ-DG in the hippocampus of ADE group were significantly increased（P<0.01）.（5）Compared with WTC group,the co-localization levels of AQP4 and β-DG in hippocampus of ADC group were significantly decreased（P<0.01）;Compared with ADC group,the co-localization levels of AQP4 and β-DG in the hippocampus of ADE group were significantly increased（P<0.05）.（6）Compared with WTC group,the m RNA expression levels of IL-1β and IL-6 in hippocampus of ADC group were significantly increased（P<0.05）,and the m RNA expression level of MMP-9 was significantly increased（P<0.01）;Compared with ADC group,the m RNA expression levels of IL-1β and IL-6 in the hippocampus of ADE group were significantly decreased（P<0.05）,and the m RNA expression level of MMP-9 in ADE group was significantly decreased（P<0.01）.Research Conclusions:（1）6-month-old APP/PS1 mice showed increased Aβ deposition in hippocampus and decreased spatial learning and memory ability,which was effectively alleviated by12-week moderate intensity treadmill exercise.（2）The expression level of AQP4 in hippocampus of APP/PS1 mice at the age of6 months was abnormally increased,and the expression levels of SNTA1 and β-DG of AQP4 anchor proteins were decreased,and their localization was changed.After 12 weeks of moderate intensity treadmill exercise,the expression level of AQP4 was inhibited,the expression level of SNTA1 and β-DG was increased,and the localization loss of AQP4 was alleviated.（3）The expressions of IL-1β,IL-6 and MMP-9 upstream regulatory factors of AQP4,SNTA1 and β-DG in hippocampus of 6-month-old APP/PS1 mice were increased,and 12-week moderate intensity treadmill exercise could effectively inhibit the expression of IL-1β,IL-6 and MMP-9 in hippocampus of APP/PS1 mice.