Time-course evaluation of irreversible electroporation, bleomycin electrochemotherapy, and IRE–bleomycin therapy in a rabbit VX2 liver model using a high-voltage generator

Electroporation-based therapies are established non-thermal ablation strategies for targeted tissue destruction. Here, a custom high-voltage pulse generator and a parallel-plate electrode system were used to deliver the irreversible electroporation (IRE), electrochemotherapy (ECT), and IRE-BLM protocols to rabbit VX2 liver tumors. The parallel-plate configuration was designed to provide a more homogeneous electric field across the target volume while avoiding direct puncture of the hepatic parenchyma by the electrodes. IRE, bleomycin-based ECT, and IRE–bleomycin therapy were evaluated at 1, 8, and 21 days after treatment using histopathology and immunohistochemistry, including p53 and Ki-67 analysis. IRE and ECT monotherapies induced marked acute tissue injury but did not prevent substantial tumor regrowth by 8 days after treatment. In contrast, the IRE-BLM protocol produced the greatest reduction in viable tumor burden, delayed tumor regrowth, and showed a 95.5% reduction in tumor volume relative to the long-term tumor control group, although residual viable tumor cells were detected at late follow-up. By day 21 after treatment, treated hepatic tissue showed an organized reparative response, with progressive remodeling of the ablated area and fibrous tissue deposition. These findings support further investigation of electroporation-based combination strategies and highlight the value of time-course follow-up in aggressive tumor models.