RESUMO
Objective:To evaluate the pathological features of a heart failure with preserved ejection fraction(HFpEF) model, which is established by spontaneously hypertensive rats (SHR) through high-fat diet and diabetic factors.Methods:Twenty specific pathogen-free grade(SPF grade) and 14-week-old SHR rats were randomly divided into SHR group (normal diet) and HFpEF group [high-fat diet combined with intraperitoneal injection of streptozotocin (STZ, 25 mg/kg) were used to create a diabetic complex model] with 10 rats in each group. Ten SPF and 14-week-old WKY rats with the same genetic background were set as blank control group (WKY group). All rats were fed for 8 weeks. Echocardiography was performed to measure cardiac parameters: peak velocity of early diastolic mitral inflow(E), peak velocity of late diastolic mitral inflow(A), and the early diastolic mitral annulus e′ in the same cardiac cycle, left atrial ejection fraction (LAEF), left ventricular ejection fraction (LVEF), left atrial diameter, right atrial diameter and interventricular septal thickness(IVST). Serological testing included glucose (GLU) and glycosylated serum protein (GSP); Enzyme-linked immunoassay (ELISA) testing included insulin (INS), glucagon (PG), C-peptide (CP), leptin (LEP), atrial natriuretic peptide (ANP) and B-type brain natriuretic peptide (BNP). The rat heart tissue was stained with HE, and the morphological changes of atrial/ventricular tissue were observed under an optical microscope.Results:The pathological characteristics of HFpEF was established in SHR rats fed with high fat and diabetes. Echocardiography showed that compared with the WKY group, the values of E, E/A and E/e′ in the HFpEF group were significantly increased (all P<0.01), and e′and LAEF were significantly reduced (all P<0.01). In the HFpEF group, the anteroposterior and tranverse dimensions of the left atrium and the long-axis dimension of the right atrium increased to varying degrees (all P<0.05), and the IVST was also significantly increased ( P<0.01). At the same time, atrial wall was thickened obviously, myocardial cells were disordered, and myocardial fibers were broken. Compared with the WKY group, the levels of serum markers ANP and BNP in HFpEF group were significantly increased (all P<0.01), and the levels of serum insulin-related indicators INS, PG, CP, LEP, GSP, and GLU increased to varying degrees (all P<0.01). Conclusions:The composite model established by SHR rats through high-fat diet and diabetic factors can simulate the Doppler echocardiographic changes and pathological features of HFpEF, as well as abnormal changes in serum related markers and insulin indicators.