An in vitro comparative study on clot lysis efficiency of urokinase and reteplase with the synergy of ultrasound needle

Objectives: Ultrasound Needle, which is an improved ultrasonic horn device, has shown great potential for promoting the diffusion of thrombolytic drugs within clots and enhancing clot lysis efficiency. However, the clot lysis efficiency of different thrombolytic drugs with the synergy of Ultrasound Needle remains unknown. In this study, we aimed to compare the lysis efficiency of the non-fibrin-specific drug urokinase and fibrin-specific drug reteplase with the synergy of Ultrasound Needle. Materials and methods: Twenty-five milliliters of human blood was incubated for 1.5 h to form in vitro clots and then received the corresponding treatment protocols: control group (normal saline), US group (10 min of Ultrasound Needle treatment), UK group (30000IU of urokinase), r-PA group (2 mg of reteplase), US + UK group, and US + r-PA group. After treatment, the morphological changes of the clots were analyzed by B-mode ultrasound imaging and hematoxylin and eosin (H&E) staining. Lysis efficiency was evaluated based on the relative end weight (final weight/initial weight). The fibrin density of the different groups after treatment was assessed by immunofluorescence staining. Results: Morphological examination and relative end weight analysis showed that combination therapies induced a more thorough dissolution of clots compared with single therapies, and the US + r-PA group exhibited higher lysis efficiency than the US + UK group. In addition, immunofluorescence staining showed that the US + r-PA group had fewer remaining thrombus fibrins than the US + UK group after treatment. Conclusions: The Ultrasound Needle can significantly improve the clot lysis efficiency of both fibrinolytic drugs, and fibrin-specific reteplase exhibited superior lysis efficiency over non-fibrin-specific urokinase with the synergy of the Ultrasound Needle.