The Effects of Irreversible Electroporation on the Colon in a Porcine Model

BACKGROUND AND AIM: Irreversible electroporation (IRE) is a method of targeted cell ablation which has been suggested as a potential cancer therapy as it leaves structures such as blood vessels and the extracellular matrix intact, thereby allowing the rapid recovery of healthy tissue. Here, we investigated the effects of IRE on the colon in vivo in a porcine model. METHODS: IRE ablation was performed on the colon walls of 12 female Tibet mini-pigs, creating a total of 24 lesions. Lesions were monitored periodically by endoscopy. The pigs were euthanized 7, 14, 21 or 28 days after IRE ablation and the colons harvested for gross and histological analysis. Sections were stained with hematoxylin and eosin (H&E), Masson’s trichrome (MT) stain and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. RESULTS: All pigs tolerated the ablation procedure without serious clinical symptoms or complications. There was no evidence of perforation by endoscopy or gross postmortem examination. All lesions were characterized by necrotic cell death with mild inflammation and hyperemia, with a sharp demarcation between ablated and adjacent normal tissue. A fibrous scar was observed in the ablated colon tissue. Histological analysis revealed damage to each layer of the colon. Histopathology findings also showed the preservation of extracellular structures and the recovery of the ablated colon. CONCLUSIONS: The complete ablation of the target area, its rapid recovery and the lack of posttreatment symptoms suggest that IRE ablation may be a promising therapy for tumors located adjacent to or violating the colon wall.