毛细血管密度对左心室肥大心肌纤维化的影响研究

Experimental study on the effects of capillaries density on left ventricular hypertrophy and myocardial fibrosis

目的探讨毛细血管密度对左心室肥大(LVH)发生发展过程中心肌纤维化的影响。方法将大鼠分为假手术对照组和升主动脉缩窄(AAC)组,构建左心室肥大模型,取出心脏,采用HE染色和天狼星红-苦味酸染色观察心肌细胞形态及纤维化程度,并检测胶原蛋白体积分数(CVF)、心肌细胞平均大小及毛细血管密度来验证心肌纤维化与毛细血管密度降低的关系。结果与假手术对照组相比,AAC组心肌细胞的平均大小增加(P<0.05),左心室后壁和侧壁I型胶原蛋白累积,成纤维细胞数量显著增加(P<0.05),LVH心肌的毛细血管密度显著降低(P<0.05),且此降低分布水平与I型胶原蛋白的分布水平具有一致性。结论左心室后壁和侧壁更易受压力超负荷引起的心脏肥大后纤维形成的影响,可能与这些区域毛细血管密度分布水平较低有关。

Objective To investigate the effects of capillaries density on left ventricular hypertrophy(LVH)and myocardial fibrosis.Methods The rats were divided into a control group and an ascending aortic constriction(AAC)group.The rat models with left ventricular hypertrophy were established,the hearts of rats were removed,HE staining and Sirius red-picric acid staining were performed to observe the myocardial cell morphology and fibrosis degree.Moreover the collagen volume fraction(CVF),average cardiomyocyte size and capillary density were detcted to verify the correlation between myocardial fibrosis and capillary density reduction.Results As compared with that in control group,the average size of cardiomyocytes in AAC group was significantly increased(P<0.05),and type I collagen accumulated in the posterior and lateral walls of the left ventricle,and the number of fibroblasts was increased significantly(P<0.05).The capillary density of LVH myocardium was significantly decreased(P<0.05),moreover,the distribution level of this reduction was consistent with that of type I collagen.Conclusion The posterior wall and lateral wall of the left ventricle are more susceptible to the effects by formation of post-cardiac hypertrophy fibers caused by pressure overload,which may be related to the lower distribution of capillary density in these areas.