High-intensity focused ultrasound ablation: an in vitro agarose gel model

Purpose: There are many ultrasound studies involve the use of tissue-mimicking materials to research phenomena in vitro and predict in vivo biological effects. The goal of our study was to establish a typical agarose gel model of high-intensity focused ultrasound (HIFU) treatment for empirical study. Materials and methods: In this study, the model consists of human pancreatic tissues embedded in an agarose gel. The Sprague Dawley (SD) rat liver tissues were encapsulated in agarose gel and ablated by HIFU. The changes in vitro after ablation were assessed using ultrasonography, pathological examination, and histochemical staining. Results: After HIFU treatment, the results showed that the ultrasonic echo signal of the ablating region was strong, and the necrosis at the center of the ablation was monitored using hematoxylin and eosin (HE) staining. Shrinkage, chromatin condensation, nuclear condensation and fragmentation of the mouse liver cancer cells were assessed during pathological examination. Acid phosphatase (ACP) and succinic dehydrogenase staining (SDH) were negative in the experimental group. Discussion: Our study demonstrated that agarose model was appropriate for HIFU ablation in in vitro human tissues. The in vitro model may provide a useful tool for studying ablation induced by HIFU and facilitate further investigation of HIFU in anticancer therapeutics.