[Establishment of rabbit model of benign circumferential esophageal stricture]

To explore the method of establishing benign esophageal stricture in rabbits by using argon plasma coagulation under endoscopy, and to provide a convenient and stable animal model for subsequent research on the prevention of esophageal stricture.

Twenty-two male New Zealand rabbits were randomly divided into three groups after completing esophageal radiography under X-ray. The blank control group (n=4) only received endoscopic examination. In the experimental group Ⅰ (n=9) and experimental group Ⅱ (n=9), argon knife was performed on the esophagus at 30 W and 50 W power, respectively, under endoscopy. Endoscopy was performed 1, 2, and 4 weeks after the operation to observe the changes in the esophagus, and the body weight and mental state were recorded. Four weeks after the operation, esophageal radiography under X-ray was performed to measure the inner diameter of the esophageal stricture and calculate the stricture index. All the experimental animals were sacrificed and esophageal specimens were obtained for histopathological examination and detection of hydroxyproline content in esophageal tissue.

In the blank control group, the body weight significantly increased 4 weeks after the operation compared with that before the operation [(4.13±0.25) kg vs. (3.10±0.39) kg, P < 0.05], and there was no significant change in the esophageal inner diameter [(12.89±0.83) mm vs. (12.83±1.07) mm, P>0.05]. In the experimental group Ⅰ, there was no significant change in the body weight and esophageal inner diameter 4 weeks after the operation compared with that before the operation [(2.91±0.28) kg vs. (2.91±0.54) kg; (11.19±0.97) mm vs. (12.06±0.32) mm; P>0.05]. In the experimental group Ⅱ, the body weight and esophageal inner diameter significantly decreased 4 weeks after the operation compared with that before the operation [(2.02±0.31) kg vs. (3.51±0.37) kg; (10.49±1.76) mm vs. (12.58±1.11) mm; P < 0.05]. The esophageal stricture index 4 weeks after the operation was significantly higher in the experimental group Ⅱ than in the experimental group Ⅰ (1.242±0.148 vs. 1.083±0.104, P < 0.05). The histopathological score and hydroxyproline content in the experimental group Ⅰ [2.55±0.52, (182.90±72.75) μg/g] and experimental group Ⅱ [4.55±0.52, (210.81±54.28) μg/g] were significantly higher than those in the blank control group [0, (91.37±29.74) μg/g] (P < 0.05).

The induction of esophageal stricture in male New Zealand rabbits using 50 W argon knife under endoscopic guidance is a feasible, depth-controllable, and reproducible method. This animal model provides a reliable platform for the development and evaluation of novel therapeutic strategies for esophageal stricture.