J Korean Med Sci.  2016 Sep;31(9):1438-1444. 10.3346/jkms.2016.31.9.1438.

Development of a Swine Benign Biliary Stricture Model Using Endoscopic Biliary Radiofrequency Ablation

• Park JS
• Jeong S
• Kim JM
• Park SS
• Lee DH

• KMID: 2468277
• DOI: http://doi.org/10.3346/jkms.2016.31.9.1438

Abstract

The large animal model with benign biliary stricture (BBS) is essential to undergo experiment on developing new devices and endoscopic treatment. This study conducted to establish a clinically relevant porcine BBS model by means of endobiliary radiofrequency ablation (RFA). Endoscopic retrograde cholangiography (ERC) was performed on 12 swine. The animals were allocated to three groups (60, 80, and 100 W) according to the electrical power level of RFA electrode. Endobiliary RFA was applied to the common bile duct for 60 seconds using an RFA catheter that was endoscopically inserted. ERC was repeated two and four weeks, respectively, after the RFA to identify BBS. After the strictures were identified, histologic evaluations were performed. On the follow-up ERC two weeks after the procedure, a segmental bile duct stricture was observed in all animals. On microscopic examination, severe periductal fibrosis and luminal obliteration with transmural inflammation were demonstrated. Bile duct perforations occurred in two pigs (100 W, n = 1; 80 W, n = 1) but there were no major complications in the 60 W group. The application of endobiliary RFA with 60 W electrical power resulted in a safe and reproducible swine model of BBS.

Keyword

Benign Stricture; Radiofrequency Ablation; Animal Experimentation; Endoscopes; Safety

MeSH Terms

Animals
Catheter Ablation
Cholangiopancreatography, Endoscopic Retrograde
Common Bile Duct/*pathology
Constriction, Pathologic
Female
Fibrosis
Inflammation
Models, Animal
Swine

Figure

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  Fig. 1 The endobiliary radiofrequency catheter (APRO Korea Inc., Gunpo, Korea) and power generator (CoATherm RF-G200; APRO Korea Inc.) used for endobiliary RFA. (A) An endobiliary RFA catheter. (B) The distal end of the RFA catheter has a 10-mm leading tip, proximal to which there is a 10-mm steel electrode. (C) An RFA generator.

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  Fig. 2 Endoscopic retrograde cholangiograms of animals obtained during endobiliary RFA. (A) Normal cholangiogram before endobiliary RFA. (B) RFA catheter positioned in distal CBD.

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  Fig. 3 Endoscopic retrograde cholangiograms after endobiliary RFA. (A) Cholangiogram at two weeks after endobiliary RFA showing stricture at site of procedure. (B) Cholangiogram at four weeks after endobiliary RFA. The silhouette of the stricture proximal margin is more apparent and proximal duct dilatation has progressed.

• 

  Fig. 4 Photomicrographs of a histologic section of bile duct with endobiliary RFA at a 60 W setting. (A) The distal part of the CBD, which is embedded in the duodenal muscle layer, reveals mild mucosal inflammation without ulcer or stricture in representative pathologic findings from the swine bile duct (H&E; original magnification 40 ×). (B) The muscle layer of distal CBD is well preserved (MT; original magnification 40 ×). (C) The RFA area of the CBD shows luminal obliteration with mucosal ulcer and transmural inflammation (H&E; original magnification 40 ×). (D) The RFA area shows destruction of muscle layer with transmural inflammation and severe fibrosis (MT; original magnification 40 ×). (E) The lumen of the proximal part of the CBD is markedly dilated. Mucosa is intact without ulcer (H&E; original magnification 12.5 ×). (F) The proximal CBD shows attenuated muscle layer (MT; original magnification 12.5 ×).

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