SD大鼠生长发育期心脏结构及功能的超声心动图评价

High Frequency Ultrasound Assessment of Developmental Changes of Ventricular Structure and Function in SD Rat

目的应用高频超声仪动态观测SD雄性大鼠生长发育阶段心脏结构和功能变化规律,为发育期实验大鼠动物模型制备及功能评价提供依据。方法利用小动物超声仪连续观测SD雄性大鼠出生后1～9周左心室结构及功能的动态变化。结果(1)M超检测结果显示左室壁厚度及左室内径随生长发育而增加,超声评估左心室重量与解剖称重结果高度相关(r=0.9326,P<0.0001);(2)左室短轴缩短率(FS%)在发育期无显著变化;(3)脉冲多普勒测定舒张早期峰值血流速度(E峰)与舒张晚期峰值血流速度(A峰)之比(E/A)>1,在发育过程中无显著性变化;(4)组织多普勒检测提示:左室后壁心肌的舒张早期(Em)、舒张晚期(Am)及收缩期(sm)运动速度出生后1～6周逐渐增加,6周时达平台期。结论高频小动物超声仪经胸超声心动图所检测的心脏结构能准确地反映大鼠心脏生长发育变化趋势;心脏整体收缩及舒张功能在出生后1周即达稳定状态;组织多普勒检测左室后壁心肌纵轴运动在出生后逐渐成熟完善,于6周达到稳定状态。

Objective To assess the developmental changes of left ventricular structure and function in male SD rats with a high frequency ultrasound system and to provide evidence for preparation of rats model and functional evaluation. Methods Using ultrasonic instrument for small animals consecutively to observe left ventricular structure and function of male SD rats aged from 1 to 9 weeks. Results （ 1 ） M-mode detection showed that left ventricular wall thickness and left ventricular inside diameter increased with aging. Ultrasound assessment of left ventricular mass showed a high correlation with anatomical results （ r = 0. 9326, P 〈 0.0001 ）. （2） There was no significant change in left ventricular fractional shortening （FS%） during developmental period. （3） Ventricular filling was quantified as ratio of early peak velocity （E wave） to atrial peak flow velocity （A wave）. In the course of development, E/A ratio is higher than 1, with no significant change. （g） Tissue Doppler imaging was applied to measure myocardial tissue velocities： LV posterior wall early diastolic （Em） , late diastolic （Am） and systolic （ Sm ） myocardial tissue velocities increased gradually from 1 to 6 weeks of age and reached to platform at 6-week. Conclusions High frequency transthoracic echocardiography for small animals can accurately reflect growth and development of rat hearts by the detection of cardiac structure. Cardiac systolic and diastolic functions stablize at 1 week after birth. Left ventricular posterior wall longitudinal axis movement detected by Tissue Doppler Imaging matures gradually after birth and stablizes in the 6th week.