Histological and Mathematical Analysis of the Irreversibly Electroporated Liver Tissue

Abstract

Irreversible electroporation has clinically been used to treat various types of cancer. A plan on how to apply irreversible electroporation before practicing is very important to increase the ablation area and reduce the side effects. Several electrical models have been developed to predict the ablation area with applied electric energy. In this experiment, the static relationship between applied electric energy and ablated area was mathematically and experimentally investigated at 10 hours after applying irreversible electroporation. We performed the irreversible electroporation on the liver tissue of Sprague Dawley rats (male, 8 weeks, weighing 250-350 g). The ablated area was measured based on histological analysis and compared with the mathematical calculation from the electric energy, assuming that the tissue is homogeneous. The ablated area increased with the increase in applied electric energy. The numerically calculated contour lines of electric energy density overlapped well with the apoptotic area induced by the irreversible electroporation. The overlapped area clearly showed that the destructive threshold of apoptosis between electrodes is electric energy density level of 5.9 Â 10 5 J/m 3 . The results of the present study suggested that the clinical results of the irreversible electroporation on a liver tissue could be predicted through mathematical calculation.

Characterization of irreversible electroporation on the stomach: A feasibility study in rats

“…In the absence of cross-sectional sliced images, it is difficult to calculate the exact threshold of critical energy density. However, we can postulate it to be around 0.8 kV/cm 42,46 . Although the submucosa and serosa were within the applied electrical field, they were not affected.…”

“…41 . The apoptosis may not be visible by histological and pathological methods as time passes 42 . This may be related to the apoptotic cell clearance mechanism 43 .…”

“…In addition, DNA degradation as revealed by the TUNEL assay peaked at 10 h after IRE, and then declined slightly at 24 h and rapidly at 48 h after IRE 46 . This suggests that the ablated tissue may rapidly recover within these times due to vigorous metabolic activity from the blood circulation 42,43,46 . Here, in Fig.…”

“…The applied electric field strength distribution is an important parameter to determine the tissue ablation by IRE. The steady state electric field distribution is obtained by solving the Laplace equation,where ∅ is the electric potential, assuming that the electrodes length is larger than the distance between the electrodes and the effect of tissue surface is neglected 42 . The electric field is calculated as the gradient of electric field potential.…”

Analytical solution of the bioheat equation for thermal response induced by any electrode array in anisotropic tissues with arbitrary shapes containing multiple-tumor nodules

“…Therapies like electrochemical treatment (EChT) [1], electrochemotherapy (ECT) [2] and radiofrequency ablation (RF) [3] have emerged as safe and effective treatments for solid tumors with minimum damage to the organism. During application of these therapies, tissue heating arises due to conduction losses (i.e., resistive heating from ion movement) [4].…”