摘要目的 探讨糖尿病大鼠病变过程中(第4、12、24周)左心室舒张功能与心肌超微结构及嗜银纤维动态改变之间的关系.方法 通过一次性大剂量腹腔注射链脲佐菌素(STZ)(65 m/kg)建立雄性SD大鼠糖尿病模型,脉冲多普勒(CDFI-PW)及多普勒组织成像(DTI)技术检测大鼠左心室舒张功能;透射电镜观察心肌超微结构,嗜银染色观察心肌嗜银纤维容积分数(APFVF);并与同龄正常大鼠组进行比较.结果(1)糖尿病组舒张功能减低最早出现在模型成功后第4周(E/A＜1),并逐渐加重,24周达二尖瓣血流假性正常阶段(E/A＞1),DTI可帮助鉴别(Ea/Aa＜1).正常组未见舒张功能异常(E/A＞1和Ea/Aa＞1).(2)透射电镜观察到糖尿病组大鼠心肌细胞的亚细胞重构,表现为肌原纤维含量减少、排列紊乱,线粒体变性,肌浆网扩张、结构紊乱等改变.糖尿病大鼠组心肌APFVF均明显增高(P＜0.05).结论 糖尿病大鼠左心室舒张功能减低与超微结构改变、心肌嗜银纤维增多密切相关.

abstractsObjective To explore the relationship between left ventricular diastolic function and the dynamic changes of myocardial ultrastructure and argyrophilic fiber in diabetic rats on the different periods of lesions(week 4,12 and 24).Methods The diabetes mellitus(DM)in healthy male Sprague-Dawley rats was induced by a single injection of streptozotocin(STZ,Sigma)into intraperitoneal at a dose of 65 mg/kg body weight.The left ventricular diastolic function was measured by Color Doppler Flow Imaging-Pulsed Wave(CDFIPW)and Doppler Tissue Imaging(DTI)echocardiography.Heart tissue at the apex was obtained rapidly for transmission electron microscope study.Argyrophilic staining was used in the study of argyrophilic fiber volume fraction(APFVF)in heart interstitial tissue.Results Diastolic dysfunction of left ventricle was detected in STZinduced diabetic rats by CDFI-PW(E/A ＜ 1)at week 4,and progressed gradually.Pseudonormal filling (E/A ＞ 1)was found in diabetic rats at week 24,which could be identified by DTI(Ea/Aa ＜ 1).Diastolic function of normal rats was not impaired(E/A ＞ 1 and Ea/Aa ＞ 1).Transmission electron microscopy revealed a spectrum of subcellular remodeling in myocardium which was characterized by myofibril content decrease,disorganization,mitochondrial degeneration,sarcoplasmic reticulum,structural disorder.Compared with the control group,APFVF in myocardium was increased significantly in diabetic rats(P ＜ 0.05).Conclusion The diastolic dysfunction in STZ-induced diabetic rats correlates with damage of ultrastructure and increase of myocardial argyrophilic fiber.