Effects Of Treadmill Exercise On Glucose Metabolism And Learning And Memory In Brain Of APP/PS1 Transgenic Mice

ObjectiveGlucose metabolic attenuation in the brain is early signal of pathology in Alzheimer's disease(AD).The objects in the study are APP/PS1 male mice.The purpose is to investigate the effects of 12-week moderate intensity treadmill exercise on the study and memory ability and glucose metabolism in brain of mice.Dependent on the metabolism,our study systematically analyzes the effects of exercise on the glucose metabolism in the mice's hippocampus,with successive cascade reactions related to glucose metabolism,including the influences of BACE1 expression,cerebral endogenous ketone body metabolism and DNA methylation,etc.In order to illustrate relative molecular mechanisms of exercise improving the study and memory ability in Alzheimer's disease in the way of cerebral glucose metabolism.MethodsGrouping: 48 identified three months-year-old APP/PS1 mice and 48 wild type mice are divided into four groups randomly.APP/PS1 mice are divided into two groups,AD control group(ADC)and AD exercise group(ADE).Wild type mice are divided into two groups,WT control group(WTC)and WT exercise group(WTE).The number of mice in every group is 24,with the same standard feeding.Training programmes: The exercise groups perform 45 min moderate intensity treadmill exercise intervention.The control groups are without exercise intervention.The intervention time is 12 weeks.Behavioral and Imaging Experiments: In the 13 th week,Morris water maze is tested for one week,so as to examine the study and memory ability in mice.After that,one day PET/CT in vivo is tested for cerebral glucose metabolism in mice.Materials and Molecular Biology Experiments:Then the materials are extracted after 12-hour fasting overnight.6 mice in each group are conducting cardiac perfusion,intraperitoneal injection anesthesia with 10% acetal hydrate(3.5ml/kg weight).After mice are in anesthesia,cardiac perfusion progress will be done first using 0.9% saline to wash the excess blood in different organisms and tissues until the liver turning white,then using 4% paraformaldehyde to do the whole body perfusion and extracting the brain immersed in 4% paraformaldehyde.Applying immunohistochemistry with paraffin section is to examine the situation of hippocampus A? deposition.The other mice are sacrificed by extracting the blood from eyes.Hippocampus is isolated to do the subsequent experiments such as ELISA,RT-q PCR and Western Blot.ELISA is adopted to test ?-OHB content in the serum and hippocampus,ATP,AMP,SAM and SAH content in hippocampus.RT-q PCR and Western Blot are adopted to test the relative m RNA level and protein expression of glucose metabolism relative indicators include GLUT1,GLUT3,HK1,PDH,p-PDH,?-KGDH,LDHA and LDHB,etc;mitochondrial relative indicators include mfn1,mfn2,OPA1,Drp1,COXIV and ATP synthetase,etc;the signaling pathway of AMPK-BACE1 relative indicators include AMPK,p-AMPK,Sirt1,PPAR?,PGC1? and BACE1,etc;ketone body metabolism relative indicators include MCT1,MCT2,MCT4,MBP,c-PLA2 and SCOT,etc;DNA methylation relative indicators include DNMT1,DNMT3 a and DNMT3 b,etc.Results(1)Compared to WTC group,study and memory ability relative indicators in ATC group mice present significant changes during Morris water maze test(p<0.05).12-week treadmill exercise can reverse these changes,specific results are that compared to ADC,the latency in the Morris water maze test of APP/PS1 mice in ADE group is significantly decreasing,p<0.05.Platform quadrant swimming time percentage,Platform quadrant swimming distance percentage and passing across platform times of ADE group mice are significantly increasing,p<0.05.(2)Compared to WTC group,glucose metabolism relative indicators in ADC group mice present significant changes(p<0.05).12-week treadmill exercise can reverse these changes,specific results are that compared to ADC group,the expression of glucose transporter key genes GLUT1 and GLUT3 is significantly increased in hippocampus of APP/PS1 mice in ADE group.The expression of glucose metabolism key enzymes genes HK1 and ?-KGDH is significantly increased,while the expression of key enzymes genes p-PDH,LDHA and LDHB is significantly decreased.The expression of mitochondrial fusion genes mfn1 and mfn2 is significantly increased,while the expression of mitochondrial fission gene Drp1 is decreased.The expression of mitochondrial biogenesis gene PGC1? is significantly increased.The expression of mitochondrial OXPHOS and ATP synthesis key genes COXIV and ATP synthetase is significantly increased.The content of ATP in hippocampus are significantly rising up,all p<0.05.(3)Compared to WTC group,relative genes in the AMPK-BACE1 signaling pathway in ADC group mice present significant changes(p<0.05).12-week treadmill exercise can reverse these changes,specific results are that compared to ADC group,the expression of p-AMPK,Sirt1,PPAR? and PGC1? in hippocampus of APP/PS1 mice in ADE group is significantly up-regulated.The expression of BACE1 in hippocampus is significantly down-regulated.A? deposition in hippocampus is significantly decreasing,all p<0.05.(4)Compared to WTC group,ketone body metabolism relative indicators in hippocampus of ADC group mice present significant changes(p<0.05).12-week treadmill exercise can reverse these changes,specific results are that compared to ADC group,serum ?-OHB content of APP/PS1 mice in ADE group is significantly increasing.?-OHB content in hippocampus is significantly decreasing.The expression of ketone transporter genes in hippocampus MCT1,MCT2 and MCT4 is significantly down-regulated.The expression of myelin basic protein MBP is significantly up-regulated,while the expression of myelin phospholipid degradation enzyme gene c-PLA2 is significantly down-regulated.The expression of ketone body metabolism key enzyme gene SCOT is significantly down-regulated,all p<0.05.(5)Compared to WTC group,DNA methylation key indicators in hippocampus in ADC group mice present significant changes(p<0.05).12-week treadmill exercise can reverse these changes,specific results are that compared to ADC group,SAM content in hippocampus of APP/PS1 mice in ADE group is significantly rising up.SAH content is significantly declining and the ratio of [SAM]/[SAH] is significantly increasing.The expression of DNA methylaiton key transferase genes in hippocampus DNMT1,DNMT3 a and DNMT3 b is increasing,p<0.05.Conclusions(1)The study and memory ability of 6 months-year-old APP/PS1 mice are declining and 12-week treadmill exercise can improve the study and memory ability of APP/PS1 mice.(2)The glucose metabolism capacity in hippocampus of 6 months-year-old APP/PS1 mice is declining and 12-week treadmill exercise can enhance the glucose metabolism capacity in hippocampus of APP/PS1 mice to maintain cerebral energy metabolic homeostasis.(3)The signaling pathway of AMPK-BACE1 in hippocampus of 6 months-year-old APP/PS1 mice is abnormal,with the increased A? deposition.12-week treadmill exercise can improve The signaling pathway of AMPK-BACE1 in hippocampus of APP/PS1 mice to decrease cerebral A? deposition.(4)Endogenous ketone body metabolism in hippocampus of 6 months-year-old APP/PS1 mice is inducible.Myelin integrity is decreasing.12-week treadmill running can inhibit endogenous ketone body metabolism in hippocampus of APP/PS1 mice to maintain myelin Phospholipid Structural Integrity.(5)DNA methylation key indicators in hippocampus of 6 months-year-old APP/PS1 mice are down-regulated.12-week treadmill running can up-regulate DNA methylation key indicators in hippocampus of APP/PS1 mice to maintain DNA methylation level.