诊断超声波联合微泡开放兔血脑屏障的初步研究

Preliminary study on opening rabbit blood-brain barrier with diagnostic ultrasound combined with microbubbles

目的探讨诊断超声波联合微泡开放兔血脑屏障的可行性,为进一步定量研究大分子药物靶向释放脑组织确定较大动物模型。方法健康新西兰大白兔10只,雌雄不限,体质量(2.30±0.43)kg;分为定量分析组和荧光观察组,各5只。经兔耳缘静脉匀速输入微泡(0.5 mL/kg)的同时两组均用诊断超声波(1.75 MHz,MI 1.9)经颅骨连续辐照兔脑10 min。伊文思蓝(EB)示踪法对照观察靶区脑组织的通透性。结果诊断超声波联合微泡能够促EB跨兔血脑屏障进入脑组织,表现为辐照靶区脑组织蓝染,靶区组织EB含量[(32.25±5.85)mg/kg]明显高于非辐照区脑组织中EB含量[(3.00±5.85)mg/kg](P<0.001)。结论微泡介导下诊断超声波能够增加兔血脑屏障的通透性;新西兰大白兔有可能用于促大分子药物跨血脑屏障转运的自身对照研究。

Objective To investigate the possibility of opening blood-brain barriers（BBB） with microbubbles combined with diagnostic ultrasound, and set up a large animal model for studying macromolecule drug targeted transporter across the BBB quantitatively. Methods Ten New Zealand white rabbits, body weight （2.30 ±0.43） kg, no limit of male or female, were randomly divided into 2 groups： quantitative analysis group and fluorescence observation group. The microbubbles（0.5 ml_/kg） were injected at equal speed via rabbit vein during 10 minutes, and the cranial was continuously irradiated with diagnostic uhrasound（1.75 MHz, MI 1.9） at the same time. The Evens blue （EB） tracer method was employed to observe the brain tissue permeability. Results The diagnostic ultrasound mediated by microbubbles could promote EB to cross rabbit BBB into brain tissues. It was shown that the target area was blue-stained and the corresponding EB contents[（32.25 ± 5.85） mg/kg] were obviously higher than that in the untargeted areas[（3.00 ± 5.85） mg/kg]（P 〈 0.001）. Conclusion It is demonstrated that diagnostic ultrasound mediated by microbubbles can increase the rabbit BBB permeability. It is possible that New Zealand white rabbits could be used as the self-control in the study on molecule drug crossing the BBB.