应用超声背向散射积分技术观察自发性高血压大鼠心肌纤维化的动态改变

目的:观察自发性高血压大鼠(SHR)血压增高的初期、增高期和稳定期心肌超声背向散射积分(IBS)与心肌内胶原含量的改变,探讨IBS与心肌纤维化的关系。方法:分别选用6、14和24周的SHR及Wistar京都(WKY)大鼠(对照组)各6只。采用Bergman氏法测定各组大鼠的心肌组织内羟脯氨酸含量(HC);应用超声背向散射积分技术获取各组大鼠室间隔基底部心肌组织的心肌超声背向散射积分(IBS)变化曲线图。应用二维超声心动图测量各组大鼠的左室短轴缩短率(FS)。结果:SHR心肌内HC和室间隔心肌IBS平均值在6周时与WKY组差异无显著性意义(P>0.05),14周时开始升高(与6周时及同期对照组间比较,P<0.05),24周时升高更明显(与6周时及同期对照组间比较,P<0.01)。SHR室间隔IBS值与其心肌内HC之间存在着良好的相关性(r=0.76,P<0.001)。SHR的左室FS和室间隔IBS随心动周期变化幅度(IBScv)值在6周时和14周时无明显变化(P>0.05),在24周时明显下降(P<0.01)。SHR与WKY的室间隔IBScv值与其FS之间均存在着良好的相关性(r=0.70,P<0.001)。结论:通过监测IBS可以观察高血压病心肌组织纤维化的程度,通过监测IBScv可以反映高血压病中晚期心肌收缩功能的改变。

Assessment of Interstitial Fibrosis in Myocardium of Spontaneously Hypertensive Rats by Myocardial Ultrasonic Integrated Backscatter

Objective:To investigate the relation between myocardial ultrasonic integrated backscatter(IBS) and myocardial fibrosis of spontaneously hypertensive rats(SHR) in the early stage,increasing stage and stable stage.Methods:The myocardial hydroxyproline concentration(HC) of 6,14 and 24 weeks old SHR and the age matched Wistar Kyoto(WKY) were measured by the Bergman's way.The IBS curves of the basal septum were acquired in several cardiac cycles.Left ventricular fraction shortening(FS) was determined by 2D echocardiography.Results: The HC and the IBS of SHR had no great alterations in the 6th week(P>0.05),but increased markedly in the 14th week(S_(14) vs S_6,P<0.05;S_(14) vs W_(14),P<0.05) and more significantly in the 24th week(S_(24) vs S_6,P<0.01;S_(24) vs W_(24),P<0.01).A correlation was found between myocardial IBS and HC(r=0.76,P<0.001).The FS and the myocardial cyclic variation in IBS(IBScv) of SHR had no great alterations in the 6th week and in the 14th week(P>0.05) but increased significantly in the 24th week(S_(24) vs S_6,P<0.01;S_(24) vs W_(24),P<0.01).A correlation was found between the myocardial IBScv and FS(r=0.70,P<0.001).Conclusion:The myocardial IBS have been demonstrated to reflect the degree of myocardial fibrosis and the myocardial IBScv have been demonstrated to reflect the alteration of the FS in SHR.