Experimental Study On Early Diabetic Cardiomyopathy Evaluated By Ultrasound Imaging

BACKGROUND Diabetes mellitus is a common chronic metabolic disease. It has becoming a severe public health problem. Diabetic cardiomyopathy is a major complication of diabetes mellitus which is a unique cardiomyopathy characterized by myocardium hypertrophy , myocardium fibrosis, transporting defect of calcium of cells level, formation of collagen of contraction protein of myocardium and abnormality of fatty acid metabolism . It is difficult to detect diabetic cardiomyopathy in the earlier period so that it has usually been neglected and could result in congestive heart failure. The death number of congestive heart failure of diabetic cardiomyopathy was over 30% of common death number of diabetes mellitus. Diagnosis and therapy for diabetic cardiomyopathy in the earlier period had already become a pressing problem. To comprehend the ultrasonic manifestation of diabetic cardiomyopathy more deeply, we designed this topic.AIM Doppler tissue imaging and colour doppler flow imaging were used to evaluate the diastole and systole dysfunction of left ventricle of diabetic cardiomyopathy induced by STZ in rabbits. The value of this two kind of doppler ultrasound in diagnosis of diabetic cardiomyopathy was matched. The mechanism of dysfunction of left ventricle of diabetic cardiomyopathy was discussed conjugating the display of pathology . Acoustics density of myocardium of diabetic cardiomyopathy was assessed by ultrasonic tissue characterization (UTC) and the value of UTC in diagnosis of earlier period of diabetic cardiomyopathy was appraised too. Our aim was to try hard to provid important useful assisted examination result for clinical doctor, then diabetic cardiomyopathypatients could be diagnosed and treated in the earlier period to postpone the development of disease and to reduce the death rate of diabetes mellitus at the last.MATERIALS AND METHODS Streptozotocin (STZ) was used to induce diabetes mellitus in New Zealand rabbits. Rabbits whose random sugar in 24 hours was over 340mg/100ml and blood sugar stabilizing for 5 days could be taken as successful model. Cardiac function was examined by DTI.CDFI and M-ultrasound in rabbits model at 2,4,6,8 weeks after the model was established successfully. Digit ultrasound meter GE System Five was used in this experiment, the frequency of detecting head is 1. 7-10MHz. It was contacted with extra-ECHOPAC workstation which pictures could be put in and analysis could be done by CDFI and DTI. In the same time , System Five was contacted with imaging collection meter which could collect imaging of left ventricle of short and long axial diastasis cut from ultrasonic meter. Analysis of gray scala was done by Photoshop6. 0. The layout of meter such as length and gain kept unchanged in the whole process of experiment. Rabbits were killed after ultrasonic examination. Then hearts of rabbits were stained by hematoxylin and eosin(HE) and Van Gieson (VG). Pathologic alteration of hearts were checked by light microscope.RESULTS (1) Diastole dysfunction of left ventricle was discovered in STZ-induced diabetic rabbits detected by tissue doppler imaging at the 4th week. They were showed that not only the tite of early period of diastole peak velocity (Ea) in mitral ring lateral wall and post-interval of left ventricle , but also the tite of Ea/Aa reduced notably. (2) Systolic dysfunction of left ventricle was discovered in STZ-induced diabetic rabbits detected by tissue doppler imaging at the 6th week. They were showed that local contraction peak velocity (Sa) of lateral wall and post-septum of mitral ring were decreased strikingly . Mean systole velocity of four various parts of mitral ring(Vm) was reduced at the 6th week. Pre-ejection period time (PEP) at post-septum and ejection time(ET) elongated at lateral wall at the 8th week. (3) Diastole dysfunction of left ventricle was founded in STZ-induced diabetic rabbits detected by colour doppler imaging at the 4-8th week. They were showed that deceleration time of E wave (EDT)was shortened at the 4th week. Chamber...