The Experimental Study Of Echocardiography Evaluation Of Right Ventricle Structure And Function In New Zealand Rabbits With Chronic Intermittent Hypoxia

Objective:Observed the changes of right ventricle (RV) structure and function of New Zealand rabbits with short-term (0～8weeks) chronic intermittent hypoxia (CIH) using echocardiography.Methods:Select24healthy male New Zealand rabbits to set up CIH animal modol for8weeks, using conventional and tissue Doppler echocardiography measure RV structure and systolic and diastolic function parameters at0,1,2,4,6,8week respectively, analyzed the trends. Executed one rabbit after every ultrasound exam, isolated heart and RV, observed the pathological changes of RV cardiomyocytes, pulmonary artery, pulmonary tissue by HE staining.Resluts:①RV structure parameters:compared with0week, RV, RA inner diameter increased at8week, RV wall thickness(RVWd) and pulmonary artery (PA) diameter had no significant changes (P>0.05);②RV diastolic function parameters: compared with0week, isovolumic relaxation time(IRT)reduced at1,2week E/E’reduced at1,2week (P<0.05), recovered normal at4,6,8week, E/A increased at4,6,8week, E’/A’ increased at8week(P<0.05);③RV systolic function parameters: compared with0week, right ventricle fractional area change (RVFAC) increased at8week, tricuspid annular plane systolic excursion(TAPSE) increased at4,6,8week (P<0.05), right ventricle myocardial performance index(RMPI) decreased at4week(P<0.05), recovered normal at6,8week, isovolumic contraction time(ICT) decreased at2,4week(P<0.05), recovered normal at6,8week. compared with0week, pulmonary blood spectrum ejection time(ET) reduced at1,2week(P<0.05), recovered normal at4,6,8week, pulmonary flow spectrum acceleration time(AT) reduced at1,2,4week (P<0.05), recovered normal at6,8week;④pathological changes:RV myocardial cells nuclear hypertrophy, stained deepened, some cytoplasm was stained loosely and lightly, showing edematous, focal necrosis and dissolve of muscle fibers, myocardial interstitial widened, local cell increased, similar to fibroblasts. Slurry, cellulose effused lung tissue, the number of small pulmonary artery cells increased in cross-section, small pulmonary artery wall thickened generally, lumen narrowed.Conclusions:①RV diastolic and systolic function showed a compensatory protection in early, structure was abnormal later than function;②RV diastolic function compensated earlier than systolic function, IRT and ICT changed earlier than other function parameters.