超声斑点追踪成像评价自发性高血压大鼠左室局部收缩功能的研究

Evaluation of the regional myocardial function in spontaneously hypertensive rats by two-dimensional speckle tracking imaging

目的应用超声斑点追踪成像(STI)技术观察自发性高血压大鼠(SHR)左室节段心肌径向应变、圆周应变及应变率的特点。方法健康Wistar大鼠10只作为对照组,SHR组10只,分别测量两组大鼠左室射血分数和短轴缩短率,以及左室短轴乳头肌平面径向、圆周方向的应变及应变率。然后处死大鼠,HE及Masson三色法染色,观察心肌纤维化的变化。结果两组大鼠左室射血分数和短轴缩短率比较差异无统计学意义。两组径向应变和径向应变率曲线分布一致,圆周应变和圆周应变率曲线分布不一致。与对照组比较,SHR组6个节段径向应变和径向应变率均减小(P<0.05),前间隔、前壁、侧壁及后间隔的圆周应变率均减小(P<0.05);6个节段圆周应变组间比较差异无统计学意义(P>0.05)。SHR早期心肌病理改变以血管周围纤维化为主,伴有间质纤维化的改变。结论 SHR左室局部心肌径向、圆周方向的应变及应变率较Wistar大鼠普遍减低,两组大鼠径向及圆周应变的分布与总体纤维化程度的综合表现有关。

Objective To observe the left ventricular segmental peak systolic radial strain （RS）, radial strain rate （RSr）, circumferential strain （CS） , cirumferential strain rate （CSr） of spontaneously hypertensive rats （SHR） by STI. Methods Echocardiography was performed in ten normal adult male Wistar rats （control group） and ten SHR （SHR group）. Fractional shortening （FS） and ejection fraction （EF） were measured with anatomical M-model echocardiography. RS, RSr,CS and CSr of six segments were measured. The rats were sacrificed. The changes of myocardial fibrosis were observed with HE and Masson staining. Results There was no statistical significance of EF and FS in two groups. The RS and RSr of SHR group were significantly lower than those of control group （P〈0.05）. Compared with the control group, CS of all segments was decreased except the anteroseptal segment, but the difference had no statistical significance. CSr of SHR group in all segments were lower than the control group, especially the anteroseptal, anterior, lateral and septal segments（P〈0.05）. CS and CSr of all segments in left ventricular short-axis views at the papillary muscle level in two groups showed significant heterogeneity, while the RS and RSs were similar in all the segments. The early pathological changes in SHR were mainly perivascular fibrosis, accompanied by changes in interstitial fibrosis. Conclusion RS, RSr, CS and CSr in SHR group are lower than in control group. The distribution of CS and RS in two groups are related to the performance of overall degree of fibrosis.