Objectives It is not fully clarified how diabetes mellitus induced cardiac dysfunction and myocardial ultrastructural changes in the early state.In the present study,we provided an integrated approach to investigate e...Objectives It is not fully clarified how diabetes mellitus induced cardiac dysfunction and myocardial ultrastructural changes in the early state.In the present study,we provided an integrated approach to investigate early changes in myocardial function of diabetic rabbits and assessed the structural alteration.Methods and Results Diabetes was induced by alloxan injection.After 30 days,echocardio- graphy and left ventricular cannulation were performed in dia- betic(D,n=8) and control rabbits(C,n= 10).After catheterization, animals were killed for histological studies.Hema-toxylin -eosin and Masson’s Trichrome staining of the heart were analyzed.The ultrastructure of left ventricle was also examined with electron microscopy.Echocardiography revealed that early diabetic cardiomyopathy had impaired LV diastolic function expressed by diminished E-waves,increased Awaves, E/A ratio reversion and increased E-wave deceleration time(EDT).Concurrently,LV end-diastolic pressure(LVEDP) and diastolic time constant(T) were increased,minimum dP/ dt(LV-dp/dt)was reduced,obtained through cardiac catheterization.There were no significant differences in LV ejection fraction(EF),LV peak systolic pressure(LVSP), or maximum dP/dt(LV + dp/dt).Qualitative light microscopy revealed no histologic changes in myocardium from diabetic rabbits.The most evident ultrastructural change was spotted myofibrillar damage,while interstitial fibrosis was slight.Conclusions These results suggest that early diabetic cardiomyopathy in animal model is characterized by left ventricular diastolic dysfunction,both impaired active relaxation and increased passive chamber stiffness.Whereas,left ventricular systolic function can remain normal.It might partly contribute to myofibrillar damage,but not myocardial fibrosis.展开更多
文摘Objectives It is not fully clarified how diabetes mellitus induced cardiac dysfunction and myocardial ultrastructural changes in the early state.In the present study,we provided an integrated approach to investigate early changes in myocardial function of diabetic rabbits and assessed the structural alteration.Methods and Results Diabetes was induced by alloxan injection.After 30 days,echocardio- graphy and left ventricular cannulation were performed in dia- betic(D,n=8) and control rabbits(C,n= 10).After catheterization, animals were killed for histological studies.Hema-toxylin -eosin and Masson’s Trichrome staining of the heart were analyzed.The ultrastructure of left ventricle was also examined with electron microscopy.Echocardiography revealed that early diabetic cardiomyopathy had impaired LV diastolic function expressed by diminished E-waves,increased Awaves, E/A ratio reversion and increased E-wave deceleration time(EDT).Concurrently,LV end-diastolic pressure(LVEDP) and diastolic time constant(T) were increased,minimum dP/ dt(LV-dp/dt)was reduced,obtained through cardiac catheterization.There were no significant differences in LV ejection fraction(EF),LV peak systolic pressure(LVSP), or maximum dP/dt(LV + dp/dt).Qualitative light microscopy revealed no histologic changes in myocardium from diabetic rabbits.The most evident ultrastructural change was spotted myofibrillar damage,while interstitial fibrosis was slight.Conclusions These results suggest that early diabetic cardiomyopathy in animal model is characterized by left ventricular diastolic dysfunction,both impaired active relaxation and increased passive chamber stiffness.Whereas,left ventricular systolic function can remain normal.It might partly contribute to myofibrillar damage,but not myocardial fibrosis.
