自发性高血压大鼠左心室心肌应变与心肌纤维化程度的相关性

Relationship between left ventricular global strain and myocardial fibrosis in spontaneously hypertension rats

目的探讨自发性高血压大鼠(SHR)左心室心肌应变与心肌纤维化程度的关系。方法选取10周龄雄性SHR及Wistar-Kyoto大鼠(WKY)各15只,均随机平均分为3个亚组。12周后每2周行常规超声及二维斑点追踪显像(2DSTE),于左心室长轴和乳头肌水平短轴切面测量左心室整体纵向应变(GLS)、径向应变(GRS)及周向应变(GCS)峰值。分别于16、20、24周将SHR和WKY各取1个亚组处死,行心脏离体固定、Masson染色,观察心内膜下和心外膜下层心肌胶原容积分数(CVF)、血管周围胶原面积与管腔面积比率(PVCA/LA)。结果与同周龄WKY相比,SHR的GLS自16周、GRS自18周、GCS自20周显著降低,差异均有统计学意义(P均<0.05)。SHR的GLS与心内膜下CVF呈正相关(r=0.65,P<0.05);GLS、GCS与PVCA/LA呈正相关(r=0.65、0.63,P均<0.05),GRS与PVCA/LA呈负相关(r=-0.59,P<0.05)。结论 2DSTE技术可无创评价大鼠心肌形变,其与心肌纤维化程度具有良好的相关性。

Objective To investigate the relationship between left ventricular strain and myocardial fibrosis in spontaneously hypertension rats（SHR）.Methods Totally 15 SHR and 15 Wistar-Kyoto rats（WKY）with 10 weeks old were observed,each group was randomly divided into 3subgroups.Echocardiography and two-dimensional speckle tracing echocardiography（2DSTE）were performed every two week from 12 weeks.two-dimensional dynamics images were required from the left ventricular long axis view and papillary muscle short axis view,and then the left ventricular peak global longitudinal strain（GLS）,radial strain（GRS）and circumferential strain（GCS）were measured.One subgroup of SHR and WKY rats were killed and hearts were isolated at 16,20 and 24weeks respectively.The myocardium were fixed and performed Masson staining to observe collagen volume fraction（CVF）in subendocardial and subepicardial myocardium,perivascular collagen area to luminal area ratio（PVCA/LA）.Results Compared with WKY rats,global strain of SHR significantly decreased,GLS significantly decreased since 16 weeks,GRS decreased since 18 weeks and GCS decreased since 20weeks（all P〈0.05）.GLS was positively correlated with subendocardial CVF（r=0.65,P〈0.05）.GLS and GCS were positively correlated with PVCA/LA（r=0.65,0.63,both P〈0.05）,and GRS was negatively correlated with PVCA/LA（r=-0.59,P〈0.05）.Conclusion 2DSTE can be used to analyze the myocardial strain non-invasively and it has a good correlation with the degree of myocardial fibrosis.