The echoeardiographic study on diabetic cardiomyopathy of rats / 中华超声影像学杂志

ABSTRACT

Objective To valuate the left ventricular function and myocardial fibrosis using Dopple tissue imaging(DTI) and integrated backscatter(IBS) in diabetic cardiomyopathy(DCM) rats. Methods Diabetes mellitus(DM) in healthy male SD rats was induced by single injection of streptozotocin (STZ,Sigma) into intraperitoneal at a dose of 65mg/kg body weight. Left ventricular fractional shortening (LVFS),ratio of peak early to late diastolic mitral inflow velocity(E/A) by color Doppler flow imaging-pulsed wave (CDFI-PW), ratio of peak early to late diastolic mitral annulus velocity (Ea/Aa) by DTI,myocardial calibrated IBS (IB%), cyclic variation of IBS(CVIB) by IBS, were determined in rats of 4,12 and 24 weeks after DM was induced. Heart weight index(HWI), Masson's trichrome staining, expression of connective tissue growth factor(CTGF) and activity of sarcoplasmic reticulum Ca2+ -ATPase(SERCA2a) in heart were measured, while the age-matched health rats served as control group. Results ① Diastolic dysfunction of left ventricular was found in diabetic rats detected by CDFI-PW(E/A<1) at the 4th week,and developed gradually. Pseudonormal filling(E/A>1) was found in major diabetic rats at the 24th week,which could be identified by DTI(Ea/Aa<1). The IB% of left ventricular posterior wall was significantly higher in diabetic rats than those in the control group( P<0.05), but the CVIB of the 24th week diabetic rats was lower(P<0.05). The LVFS had no great alteration in six groups(P>0.05).②Compared with the control group, the activity of SERCA2a was reduced, while HWI, collagen volume fraction(CVF),perivascular collagen area(PVCA) and the expression of connective tissue growth factor(CTGF) protein in heart were increased in diabetic rats (P<0.05), and correlation between IB% and HWI, CVF, PVCA,CTGF was significant (P<0.05). Conclusions DTI and IBS can assess early left ventrieular diastolic function and fibrosis of diabetic cardiomypathy in STZ-induced diabetic rats. DTI echoeardiography can identify "pseudonormal" mitral inflow patterns. DCM may be relatived with overexpression of CTGF and decreasion of SERCA2a activity.