Effects Of AMPK?2 Gene Deficiency On Exercise Induced Cardiac Hypertrophy In Mice

ObjectiveThe purpose of this study is to explore the role of AMPKa2 in exercise induced cardiac hypertrophy by using AMPK?2 knock out mice and treadmill running model.MethodsAMPK a2 knock out(KO,n=18)and wild type(WT,n=18)mouse were randomly divided into four groups as wild type control(WT+ Ctr,n=6),wild type exercise(WT+EX,n=12),AMPK a2 KO control(KO+Ctr,n=6)and AMPK a2 KO exe?rcise(KO+EX,n=12).WT+EX and KO+EX group mice were applied to treadmill running for 7 weeks to induce cardiac hypertrophy.Echocardiography was used to measure ventricular dimension and function.Cardiac fibrosis and myocyte size were evaluated by Sirius red staining and WGA staining seperately.The protein expression in heart tissue was analyzed by Western blots.Results1.Mice echocardiography results showed that there were no significant differences among four groups for ventricular dimension and function before treadmill running(p>0.05).After 7 weeks treadmill running,EF in WT+EX and KO+EX group trended to increase slightly as compared to their control(p>0.05),while IVS;S in WT+EX and KO+EX were significant higher than their control group(p<0.05).LVPW;S in KO+EX group was significant higher than WT+EX group(p<0.05).2.AMPKa2 gene deficiency had no effect on HW/BW and myocyte size under control condition(p>0.05).After 7 weeks exercise training,WT+EX and KO+EX group mice had greater HW/BW and myocyte size as compared to their control mice(p<0.05),and KO+EX group were significant higher than WT+EX group(p<0.05).3.There were no significant difference on cardiac fibrosis among four groups(p>0.05).4.Seven weeks exercise training significantly increased cardiac tissue AMPK a protein expression in both WT+EX and KO+EX as compared to their control groups(p<0.05),while there was no significant different for p-AMPKThr172 expression change significantly in cardiac tissue(p>0.05),there were no significant difference among four groups(p>0.05).Conclusion:1.Seven weeks treadmill running could induce cardiac hypertrophy in mice with increased heart weight and myocyte size.2.AMPK a2 gene deficiency significantly amplified exercise induced cardiac hypertrophy in mice.3.Seven weeks treadmill running induced cardiac hypertrophy was not founded with cardiac fibrosis.