实时心肌超声造影评价糖尿病早期心肌血流灌注改变的实验研究

目的：探讨实时心肌超声造影（RT-MCE）技术检测糖尿病（DM）早期大鼠心肌血流灌注异常的价值。方法：24只雄性SD大鼠中随机选取12只通过腹腔注射链脲佐菌素建立DM模型（DM组），剩余12只大鼠作为对照，腹腔注射等量枸橼酸缓冲液。模型建成8周后，在静息状态下，对两组大鼠行RT-MCE检查，检测两组大鼠乳头肌水平左室壁感兴趣区的峰值声学强度（A）以及造影剂的灌注速度（β），并计算出心肌血流量（A×β）。RT-MCE检查结束后，处死大鼠取心肌组织，行CD31免疫组织化学染色检测心肌微血管密度（MVD），然后对DM组A与MVD进行相关分析。结果：与对照组比较，在静息状态下DM组的A及A＆#215;β较对照组明显减低，差异具有统计学意义（P＜0.01），β较对照组减低，但差异无统计学意义（P＞0.05）。DM组的MVD较对照组明显减低（P＜0.01）。DM组A与MVD呈线性正相关（r=0.903，P＜0.01）。结论：DM早期即可发生心肌血流灌注的异常，RT-MCE在检测DM早期心肌血流灌注异常方面具有重要的应用价值。

Value of real-time myocardial contrast echocardiography in the detection of the myocardial perfusion abnormalities in early diabetic rats model

Objective： To explore the value of real-time myocardial controast echocardiography to detect myocardial perfusion abnormalities in early diabetic rats.Methods： Among twenty-four male SD rats, twelve rats were randomly selected as DM group which were induced with streptozotocin, the remain twelve rats as normal control group which were induced with buffer solution. Eight weeks after diabetic model established, all rats underwent MCE examination at the resting state. The plateau intensity （A）, initial slope of the curve （β） and myocardial blood lfow （A×β） of left ventricular anterior wall at the papillary muscle level were measured in left ventricular short-axis view by MCE. At last, myocardial tissue of the rats were stained with CD31 immuno-histochemistry to detect myocardial microvascular density （MVD）. The correlation between A and MVD at DM group was analyzed.Results： Compared with the control group, A and A＆#215;β in DM group were obviously lower （P〈0.01）, β in DM group was also lower, but without statistical difference. The MVD in the DM group was sig-niifcantly decreased compared with the control group （P〈0.01）. There were signiifcant positive correlations be-tween A and MVD at DM group （r=0.903,P〈0.01）.Conclusion： MCE can be used to detect the left ventricular myocardial perfusion abnormalities in early diabetic rats and has important application value in diagnosis of the diabetic cardiomyopathy.