Biphasic Regulation of Apoptosis Following Gastric Irreversible Electroporation Using Tissue Immunohistochemistry of Activated Caspase-3 with TUNEL Method

초록

Simple Summary: Gastric cancer remains the leading cause of death worldwide. Irreversible electroporation is a relatively new ablation technique used for cancer treatment. The present study employed tissue immunohistochemistry to semi-quantitatively assess apoptosis levels in the stomach following irreversible electroporation. This study was designed to understand how changes in the intensity of electrical energy levels influence the expansion and restoration of the apoptotic area within the stomach. As the electrical amplitude increases, the immunohistochemistry of activated cleaved caspase-3 increases, followed by a subsequent decrease, whereas TUNEL staining continues to increase. Masson's trichrome staining revealed the number of fibroblasts to increase for 7 days, returning to baseline levels by day 14. Apoptosis is biphasically regulated by electrical energy. The efficacy of tumor destruction by irreversible electroporation does not improve linearly with higher electrical intensity; rather, optimal apoptosis arising from the immunological cascade occurs at specific energies. Other electrical parameters should be further investigated. The regulation of apoptosis is the primary goal of ablation therapy. Irreversible electroporation (IRE) is a promising non-thermal tissue ablation-based therapy that induces apoptosis by manipulating electrical conditions. This study aimed to investigate IRE-induced gastric tissue apoptosis in response to changes in the electric field intensity, followed by the repair process. Among the 52 rats used in this study, 24 were used to explore apoptosis, and 28 were used to study regeneration. The apoptosis-to-necrosis ratio of the electrical field strength was evaluated using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling and caspase-3 immunohistochemistry. The size of IRE-induced ulcers in the gastric tissue continuously increased with increasing electrical intensity (r(2) = 0.830, p < 0.001). The level of apoptosis gradually decreased after peaking at 200 V (1000 V/cm). The size of the 400 V-ablated ulcers continued to decrease, and they were not visible by day 14. The proliferation and migration of epithelial cells with fibroblasts were observed on day 3 and augmented on day 7 post-ablation. This investigation demonstrated the biphasic activation of apoptosis with respect to the electrical field strength. Visually and histologically, IRE-induced gastric ulcers demonstrated complete tissue regeneration after two weeks.

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