Influence of contrast agent dose and ultrasound exposure on cardiomyocyte injury induced by myocardial contrast echocardiography in rats
Influence of contrast agent dose and ultrasound exposure on cardiomyocyte injury induced by myocardial contrast echocardiography in rats
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DOI：
10.1148/radiol.2371041467
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发表时间：
2005-10-01
期刊：
影响因子：
19.7
通讯作者：
Armstrong, WF
中科院分区：
文献类型：
--
作者：
Miller, DL;Li, P;Armstrong, WF
目的：检测大鼠心肌造影剂增强超声心动图（即心肌造影超声心动图）引起的特异性心肌细胞损伤，并确定造影剂剂量和超声暴露对此损伤的影响。 材料和方法：所有动物操作均经大学动物使用和护理委员会批准。在 61 只麻醉大鼠中，以 1.5 MHz 频率进行 1:4 心电图 (ECG) 触发的心肌造影超声心动图检查。注射伊文思蓝（EB）染料作为心肌细胞损伤的活体染色剂。在持续10分钟的心肌造影超声心动图开始时，通过尾静脉注入基于perflutren脂质微球的造影剂5分钟。根据心电图记录计算早搏。使用荧光显微镜测定心肌造影超声心动图后 24 小时获得的心脏标本切片上的 EB 染色细胞数量，然后新鲜冷冻或包埋在石蜡中。采用t检验和Mann-Whitney秩和检验对结果进行统计学比较。结果：EB染色细胞集中在心肌前部区域。在石蜡包埋的标本中，EB 染色的细胞通常伴随着炎症细胞浸润区域，但大部分与炎症细胞浸润区域分开。在用 50 μL/kg 剂量的微球造影材料触发收缩末期时，EB 染色的细胞计数随着峰值稀疏压力幅度的增加而增加，相对于假心肌造影超声心动图的细胞计数，在 1.6 MPa (P < .02) 和 2.0 MPa (P < .005) 下细胞计数显着增加。早搏也有类似的暴露-反应关系。然而，早搏次数和 EB 染色细胞计数似乎没有直接相关（决定系数 r(2) = 0.03）。舒张末期触发时的 EB 染色细胞计数与收缩末期触发时的细胞计数没有显着差异 (P > .1)。 EB染色细胞计数随着造影剂剂量的增加而增加，在2.0 MPa下，从10μL/kg增加到50μL/kg。结论：在大鼠心肌超声心动图检查中，超声脉冲与造影剂微泡的相互作用诱导了心肌细胞损伤，并且损伤细胞的数量随着造影剂剂量和超声暴露的增加而增加。 (c) 北美放射学会，2005 年。
PURPOSE: To detect specific cardiomyocyte injury induced by myocardial contrast material-enhanced echocardiography (ie, myocardial contrast echocardiography) in rats and to ascertain the influences of contrast material dose and ultrasound exposure on this injury.MATERIALS AND METHODS: All animal procedures were approved by the university committee for the use and care of animals. Myocardial contrast echocardiography with 1:4 electrocardiographic (ECG) triggering was performed at 1.5 MHz in 61 anesthetized rats. Evans blue (EB) dye was injected as the vital stain for cardiomyocyte injury. At the start of myocardial contrast echocardiography, which lasted 10 minutes, perflutren lipid microsphere-based contrast material was infused through the tail vein for 5 minutes. Premature heartbeats were counted from the ECG record. The numbers of EB-stained cells counted on sections of heart specimens obtained 24 hours after myocardial contrast echocardiography and then either fresh frozen or embedded in paraffin were determined by using fluorescence microscopy. Results were compared statistically by using t tests and Mann-Whitney rank sum tests.RESULTS: EB-stained cells were concentrated in the anterior region of the myocardium. In the paraffin-em bedded specimens, EB-stained cells were often accompanied by but largely separate from areas of inflammatory cell infiltration. At endsystolic triggering with a 50 mu L/kg dose of microsphere contrast material, the EB-stained cell count increased with increasing peak rarefactional pressure amplitude, with significantly increased cell counts at 1.6 MPa (P < .02) and 2.0 MPa (P < .005) relative to the cell counts at sham myocardial contrast echocardiography. Premature heartbeats had a similar exposure-response relationship; however, number of premature heartbeats and EB-stained cell count did not appear to be directly related (coefficient of determination r(2) = 0.03). The EB-stained cell counts at end-diastolic triggering were not significantly different from those at end-systolic triggering (P > .1). EB-stained cell counts increased with increasing contrast material dose, from 10 to 50 mu L/kg, at 2.0 MPa.CONCLUSION: Cardiomyocyte injury was induced by the interaction of ultrasound pulses with contrast agent microbubbles during myocardial contrast echocardiography in rats, and the numbers of injured cells increased with increasing contrast agent dose and ultrasound exposure. (c) RSNA, 2005.