应用琼脂糖流动腔模型评价携αvβ3-整合素单抗超声微泡靶向血栓效能

Molecular imaging of thrombus with microbubbles targeted to αvβ3-integrin using an agarose flow chamber model

目的体外评价携αvβ3-整合素单抗超声微泡(MBp)靶向血栓的黏附效能。方法将采用"亲和素-生物素"桥接法构建的MBp和同型对照微泡(MB)随机注入自制琼脂糖流动腔模型内,与人血栓孵育30min后,PBS液15cm/s流速不间断冲洗血栓,分别在冲洗血栓2﹑4﹑6﹑8﹑10min时行对比超声检查并测量声强度(VI)值。结果MBp孵育组血栓VI值较冲洗前减小了28%～66%,而对照MB孵育组血栓VI值减小了87%～94%。VI值在各时间点MBP组均较MB组大(P<0.05)。结论MBp具有较好的靶向结合血栓效能,靶向血栓黏附后能抵抗一定的剪切应力。体外模拟体内剪切应力血流环境评价MBp的靶向血栓黏附效能将有助于预测MBp应用于体内血栓超声分子成像的效果。

Objective To assess the binding ability of microbubbles targeted to αvβ3-integrin （MBp） for thrombus-targeted contrast-enhanced ultrasound. Methods Targeted microbubbles were prepared by conjugating the monoclonal antibody against αvβ3-integrin to lipid shell of the microbubble via the avidin-biotin bridges. Equivalent isotype control microbubbles （MB） or targeted ultrasound microbubbles （MBp） were randomly added into the flow chamber. After a 30-min incubation with the thrombus fixed in an agarose flow chamber model, the thrombus was washed with a continuous flow of PBS solution （15 cm/s） for 2, 4, 6, 8 and 10 min, followed by thrombus imaging using contrast-enhanced ultrasound and measurement of the video intensity （VI） values of the images. Results The VI of the thrombus in MBp group was reduced by 28%-66%, while that in control MB group was decreased by 87%-94%, and the VI values of the thrombus group were significantly greater in former group at each of the time points （P0.05）. Conclusion MBP has good targeting ability to the thrombus with resistance to the shear stress after adhesion to the thrombus. In vitro evaluation of the thrombus-binding capability of the targeted microbubble （MBp） by simulating the shear stress in vivo can be helpful for predicting the in vivo effects of ultrasonic molecular imaging using MBp.