低强度聚焦超声联合全氟戊烷相变纳米粒治疗冠状动脉血栓栓塞的体外溶栓效率及安全性研究

Thrombolytic efficiency and biosafety of low-intensity focused ultrasound combined with dodecafluoropentane phase-change nanoparticles in the treatment of coronary embolism:an in-vitro experimental study

目的评价低强度聚焦超声(LIFU)联合全氟戊烷(DDFP)相变纳米粒靶向助溶人工血管内血栓的溶栓效率,探讨其治疗急性心肌梗死冠状动脉血栓栓塞的有效性及生物安全性。方法采用声振乳化法制备DDFP脂质相变纳米粒,检测其一般性能。取家兔颈总动脉血制备成统一规格约(0.2 ml)的条形血栓,分为3组:PBS对照组(A组)、声诺维微泡组(B组)和DDFP相变纳米粒组(C组)。将各组血栓条块置入体外溶栓模拟循环装置的人工血管中,同时联合LIFU靶向辐照,优化LIFU辐照参数(时间、功率、频率、占空比),分析LIFU和纳米粒的安全性,探索最佳溶栓条件。称量溶栓前后血栓质量评价溶栓效率,观察并比较血栓HE染色内部结构;评价不同浓度纳米粒和不同强度LIFU对人脐静脉血管内皮细胞(HUVECs)存活率的影响。结果制备好的DDFP相变纳米粒粒径为(542.6±28.4)nm;纳米粒在液体相时结构稳定,大小均一,分散性好。当LIFU的参数调整为辐照强度6 W、辐照时间20 min时,DDFP相变纳米粒的相变转化率、溶栓效率及HUVECs的存活率均较高,达到最优化的相变效率和溶栓效果,同时保证了其生物安全性。溶栓后C组血栓HE染色显示红细胞及血小板梁数量显著减少,质地松软,结构疏松。结论 LIFU联合DDFP相变纳米粒可有效助溶人工血管内血栓,不仅高效且具有较好的生物安全性,有望为治疗急性心肌梗死提供一种新的方式。

Objective To explore the efficiency of low-intensity focused ultrasound(LIFU) combined with dodecafluoropentane(DDFP)phase-change nanoparticles in the thrombolytic therapy,and to evaluate the effectiveness and the biological safety of the treatment in acute myocardial infarction(AMI).Methods The DDFP nanoparticles were prepared by acoustic emulsion method,and the characteristics of the nanoparticles were detected.15 pieces of 0.2 ml thrombus prepared with carotid artery blood of the rabbits were divided into three groups:poly butylene succinate buffer(PBS)as blank control(group A),SonoVue microbubbles as group B and DDFP phase-change nanoparticles as group C.Thrombus in three groups were placed into an artificial blood vessel model in an extracorporeal thrombolysis simulator combined with LIFU irradiation.Different parameters(time,power,frequency,duty ratio)of LIFU were optimized regarding to the biosafety with LIFU and nanoparticles.The weights and pathological presentations of the thrombus were compared before and after thrombolysis.The influence of different concentrations of nanoparticles and different parameters of LIFU on the survival rates of human umbilical vein endothelial cells(HUVECs)was evaluated.Results The average size of DDFP nanoparticles was(542.6±28.4)nm.Fluorescence microscopy showed that the structure of nanoparticles was stable and uniformed in size.When the parameters of LIFU were adjusted to 20 min in irradiation time and 6 W in power,the phase transformation rates,thrombolysis efficiency and the survival rates of HUVECs were higher than those of other conditions.HE-staining slides showed that the number of red blood cells and platelets were decreased significantly after thrombolysis in group C,also the texture and structure were softer and looser.Conclusion LIFU combined with DDFP phase-change nanoparticles can effectively dissolve coronary thrombosis.This novel treatment is not only efficient,but also better for biosafety,which has the potential to provide a new treatment for AMI.