小动物超声仪与临床用超声仪评价小鼠心脏重构的对比分析

Echocardiographic evaluation of pressure overload-induced cardiac remodeling in mice using different ultrasound machines

目的比较不同类型超声仪对小鼠压力负荷下心脏重构的评价结果。方法 C57 BL/6小鼠18只,随机分为假手术(sham)组和主动脉弓缩窄(TAC)组,每组9只。手术8周后,首先应用连接15L8高频探头的临床用西门子超声仪测定TAC组小鼠心功能,并比较清醒和麻醉状态下的差异。然后比较西门子超声仪和小动物用高分辨超声仪(Vevo770)对心功能评价的影响。结果与清醒状态相比,异氟烷吸入麻醉小鼠的心率和左室短轴缩短率显著降低(P<0.001),而左室内径显著增加(P<0.05)。但与相应的sham组比较,两种仪器都可以较敏感地反映TAC组的心脏重构。与西门子超声仪相比,小动物超声仪的分辨率明显增高,并可通过二尖瓣血流频谱图评价左室舒张功能,但暂不能在小鼠清醒状态下评价心功能。结论麻醉本身会降低心功能,但在反映干预手段对心脏重构的影响程度上与清醒状态下有可比性。高分辨小动物超声仪在评价左室舒张功能方面优于西门子超声仪。

Objective To compare the results of echocardiographic evaluation of pressure overload-induced cardiac remodeling in mice using different ultrasound machines.Methods Eighteen C57 BL/6 mice were randomly divided into the sham-operated and the transverse aortic constriction（TAC） groups（n=9）.Eight weeks after the operation,the cardiac function of TAC group was evaluated using Siemens ultrasonic instrument with 15L8 probe and the differences between the awake and anesthetized states were compared.The heart rate,left ventricular（LV） dimensions,systolic and diastolic functions were measured in both sham-operated and TAC groups using the Siemens ultrasonic instrument and a high-resolution ultrasonic imaging system for small animals（Vevo 770）.Results Compared with the mice in wakefulness,the anesthetized mice showed significantly decreased heart rate and LV fractional shortening（P0.001） and markedly increased LV end diastolic diameter and LV end systolic diameter（P0.05）.Both machines sensitively detected the cardiac remodeling of TAC mice in comparison with the sham-operated group.Compared with Siemens machine,Vevo 770 provided a higher resolution of 2D and M mode echocardiography with clearer Doppler frequency image of the mitral valve flow for evaluation of the LV diastolic function.Conclusion Both machines are suitable for evaluating cardiac remodeling induced by pressure overload independent of anesthesia,though anesthesia depresses cardiac function.Vevo 770 is optimal to evaluate LV diastolic function in mice.