Basic Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Oncol. Feb 15, 2021; 13(2): 109-118
Published online Feb 15, 2021. doi: 10.4251/wjgo.v13.i2.109
Influence of the heat irrigating effect of radiofrequency ablation on regional liver tissue in Bama miniature pigs
Jian Feng, Song Wang, Kai Jiang
Jian Feng, Kai Jiang, Department of Hepatobiliary Surgery, Chinese PLA General Hospital, Beijing 100853, China
Song Wang, Department of General Surgery, Taizhou Central Hospital (Taizhou University Hospital), Taizhou 318000, Zhejiang Province, China
Author contributions: Jiang K is the guarantor of the integrity of the entire study, carried out the study design, defined the intellectual content, participated in the literature research, and reviewed the manuscript; Feng J and Wang S performed the research, wrote the first draft, and analyzed the data; Wang S is considered a co-first author; all authors read and approved the final manuscript.
Institutional animal care and use committee statement: The operational procedures for the animal experiments were approved by the Institutional Animal Care and Use Committee (IACUC) of PLA General Hospital.
Conflict-of-interest statement: The authors declare that they have no competing interests.
Data sharing statement: No additional data are available.
ARRIVE guidelines statement: The authors have read the ARRIVE Guidelines, and the manuscript was prepared and revised according to the ARRIVE Guidelines.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Kai Jiang, MD, PhD, Director, Doctor, Surgeon, Department of Hepatobiliary Surgery, Chinese PLA General Hospital, No. 28 Fuxing Road, Beijing 100853, China. jiangk301@126.com
Received: October 27, 2020
Peer-review started: October 27, 2020
First decision: November 18, 2020
Revised: November 30, 2020
Accepted: December 11, 2020
Article in press: December 11, 2020
Published online: February 15, 2021
Processing time: 97 Days and 1.1 Hours
ARTICLE HIGHLIGHTS
Research background

The results of the heat irrigating effect of radiofrequency ablation (RFA) are uncertain, and the accurate impact of the heat irrigating effect on regional liver tissue is unknown due to a lack of control experiments.

Research motivation

We carried out strictly designed and controlled animal experiments to determine the general status of 2 groups of Bama miniature pigs after RFA.

Research objectives

We assessed the influence of the heat irrigating effect of RFA on the regional liver tissue of Bama miniature pigs.

Research methods

Eight Bama miniature pigs were randomly divided into the observation group (group A) and the control group (group B), with 4 pigs/group. An RFA electrode needle was implanted near the hepatic segment vasculature (3-5 mm far from the hepatic segment portal vein) under ultrasound guidance in group A. Similarly, an RFA electrode needle was implanted far from the hepatic segment vasculature (8-10 mm from the hepatic segment portal vein) in group B. The left internal lobe and right medial lobe were chosen as RFA sites in each pig. RFA was performed at the left internal lobe on one day, and then at the right medial lobe 7 d later. Each RFA lasted 12 min. The general status and serious complications in these animals were observed during the perioperative period. The pigs were sacrificed and the livers were removed immediately after RFA on the eighth day. The samples were roughly observed. Hematoxylin-eosin and Ki67 staining, as well as TUNEL detection, were performed on the tissue sections.

Research results

All 8 animals successfully underwent ultrasound-guided RFA. No serious complications, such as massive hemorrhage, biliary fistula, severe pleural effusion, pneumothorax, peripheral organ failure, or renal failure occurred in any of the animals during the perioperative period. The RFA coagulative necrosis lesion was spherical and the surrounding liver tissue showed an inflammatory response. The difference in the Suzuki score of the liver tissue surrounding the ablated portal vein, and its distal area between groups A and B, was statistically significant (P < 0.05). More apoptotic cells were seen in liver tissue surrounding the ablated portal vein and its distal area in group A, while fewer apoptotic cells were observed in the same area in group B. The difference in the apoptotic index of the above area between group A and group B was statistically significant (P < 0.05). Cells staining positive for Ki67 were observed in liver tissue at the left internal lobe around the ablated portal vein and its distal area in group A, while no Ki67 staining positive cells were seen in other tissue sections. The difference in the Ki67 staining positive index of the above area between group A and group B was statistically significant (P < 0.05).

Research conclusions

Changes due to thermal damage occurred in the liver tissue around the ablated portal vein and its distal area as a result of the heat irrigating effect when the RFA electrode tip was close to (< 5 mm) the portal vein.

Research perspectives

When the tip of the RFA electrode is close to the portal vein (5 mm), the thermal irrigation effect during RFA causes thermal injury to liver tissue and the corresponding portal vein drainage area.