Research On Left Ventricular Function Early Changes In Type 1 Diabetic Rabbits With The Time-motion Curves Of Omnidirectional M-mode Echocardiography

Objective:1.early myocardial motion changes in rabbits with type I diabetes mellitus (DM).had been studied by the omni-directional M-mode echocardiography in order to help to diagnosis the diabetic cardiomyopathy (DCM) early. 2.Compared with conventional two-dimensional ultrasound techniques to explain the each value in evaluation left ventricular function of diabetes.Methods:96 New Zealand white rabbits were randomly divided into three groups, C group, DM group and HL group, then each group divided into four sub-groups by time,as 2 weeks group,4 weeks group,6 weeks group and 8 weeks group(each group cotiains 8). Diabetes model induce:80 mg/kg of alloxan (ALX) was intravenously injected,while 32 rabbits were fed high fat diet to induce Hyperlipidemia model (HL). Each group were killed after the ultrasonic examination, take heart tissue for HE,MASSON staining and electron microscopy observation, as well as taking blood samples to teste NT-Pro BNP,cTnI,blood sugar and blood lipids. Two-dimensional ultrasound index:mitral flow propagation velocity (VP), left ventricular ejection fraction (EF), Peak systolic velocity of mitral annulus (Sa), doppler tissue imaging (DTI) and in omni-directional M-mode echocardiography: time to the peak velocity of systolic (TS), time to the peak velocity of diastolic (TD).Reaults:In Omni-directional M-mode echocardiography research.there is meaningful extension of TD at the anterior wall in the first 2 weeks (P<0.05) in DM groups, while the TS in the first 4 weeks; there is significantly prolonged of TD (P <0.05) at the anterior wall in the first 4 weeks in HL groups, while the TS in the first 6 weeks. In Two-dimensional echocardiography technology,VP and E/A significantly reduced at the first six weeks (P<0.05) while the EF,Sa were significantly lower in the first 8 weeks (P<0.05) in the DM and HL groups.2. Pathological:in the light microscope, DM and HL groups at 4 weeks show cardiac myocyte disarrangement,cytoplasmic vacuolization and lipid deposition in varying degrees, while electron microscopy at 2 weeks show an increase in the number of swellinged and degeneration mitochondria, evident vacuolization and collagen deposition increased.3. cTn, BNP tested at all stages show no significant difference between the three groups (P>0.05).Conclusions:1.2 weeks after the DM. model induced,left ventricular systolic and diastolic dysfunction began as the TD and TS prolonged in local tissue of the heart, feature as myocardial diastolic dysfunction earlier than systolic. myocardial systolic and diastolic dysfunction occurs in HL groups later than the diabetic group.2. Result of cTnl tested excluded the coronary heart disease, myocardial fiber dissolution, increased glycogen, lipid deposition, the number of mitochondria increased, swelling, degeneration, vacuolization apparent, increase in collagen deposition and myocardial interstitial fibrosis is the main pathological changes of the DM heart tissue.3. myocardial function in diabetic rabbit change in the omni-directional M-mode echocardiography earlier than the two-dimensional ultrasound, as omnidirectional M-mode echocardiography has an advantage than the two-dimensional ultrasound in detecting of early myocardial injury of diabetes.