Non-thermal ablation of rabbit liver VX2 tumor by pulsed high intensity focused ultrasound with ultrasound contrast agent: Pathological characteristics

Figure 1 Gross specimen from PHIFU + UCA group before and after TTC staining. A: Before TTC staining, tumor tissues resembled gray fish meat, and the boundary between tumor and normal tissues was very clear; B: After TTC staining, tumor tissues were uniformly stained red, without unstained regions.

Figure 2 Light microscopic pathology of the targeted VX2 tumor rabbit liver tissues in sham group (A) and PHIFU + UCA group (B) (HE, x 400). A: In sham group, tumor cells were large, irregularly arranged and with irregular morphology. The nuclei were large and deeply H&E stained, with great karyoplasmic ratio and increased mitosis. B: In PHIFU + UCA group, tumor cytoplasm in all 10 rabbits was lightly stained, with cytoplasmic vacuoles of various sizes, chromatin margination and karyopyknosis.

Figure 3 Ultrastructure of the targeted VX2 tumor tissues in sham group and PHIFU + UCA group under transmission electron microscope. A: Tumor cells in sham group were pleomorphic or spindle-shaped of various sizes and with mitosis; nuclei were large and deformed, with clear nuclear membranes and rich euchromatin; chromatin particles were large with intranuclear pseudo-inclusions; there were multiple visible nucleoli (sham group, lead dyeing, × 3500); B: Tumor cells reduced in size; in some tumor cells, karyopyknosis was revealed, with chromatin margination and intercellular space widening (PHIFU + UCA group, lead dyeing, × 4000); C: High electron-density apoptotic bodies were present (PHIFU + UCA group, lead dyeing, × 8000); D: Vacuoles were present in cytoplasm of tumor cells (PHIFU + UCA group, lead dyeing, × 8000).