背景:磁压缩技术已用于建立气管食管瘘(TEF)的动物模型,但是普通形状的磁体存在TEF的差的均匀性和差的模型控制的限制。我们设计了一个T形磁体系统来克服这些问题,并通过动物实验验证了其有效性。
目的:研究T形磁体系统在建立比格犬TEF模型中的有效性。
方法:将12只小猎犬随机分配到T形方案的磁铁组(研究组,n=6)或正常磁铁(对照组,n=6)在胃镜下分别植入气管和食道。操作时间,手术成功率,并记录了意外伤害。手术后,观察咳嗽的存在和时间以及磁铁脱落的时间。对照组犬在咳嗽后经X线和胃镜检查后安乐死,以确认建立TEFs,并获得了TEF的总标本。研究组犬在术后2周进行X线和胃镜检查后实施安乐死,并获得了大体标本。测量所有动物的瘘管大小,然后用苏木精和伊红(HE)和Masson三色染色检查采集的瘘管标本。
结果:两组手术成功率均为100%。研究组手术时间(5.25min±1.29min)与对照组(4.75min±1.70min,P=0.331)差异无统计学意义。没有出血,穿孔,或在手术过程中任何动物都发生了计划外的磁铁吸引。在术后早期,所有的狗都吃得很自由,一般情况都很好。对照组犬术后6~9d饮水后出现剧烈咳嗽。X光显示磁铁已经进入胃部,胃镜检查显示TEF形成。来自对照组的TEF的大体标本显示形成了直径为4.94mm±1.29mm的瘘管(范围,3.52-6.56mm)。HE和Masson三色染色显示瘘管处的疤痕组织形成和分层结构紊乱。研究组犬术后未出现明显咳嗽。术后2周X线检查提示固定磁铁定位,胃镜检查显示磁铁位置无变化。在内窥镜下使用圈套器移除磁体,并观察到TEF。大体标本显示出形状良好的瘘管,直径为6.11mm±0.16mm(范围,5.92-6.36mm),超过对照组(P<0.001)。通过HE和Masson三色染色在瘘管内表面观察到疤痕形成。结构比对照组更有规律。
结论:使用改良的T形磁体方案对于建立TEF是安全可行的,与普通磁体相比,可以实现更稳定,更均匀的瘘管尺寸。最重要的是,该模型提供了更好的可控性,这提高了后续研究的灵活性。
BACKGROUND: The magnetic compression technique has been used to establish an animal model of tracheoesophageal fistula (TEF), but the commonly shaped magnets present limitations of poor homogeneity of TEF and poor model control. We designed a T-shaped magnet system to overcome these problems and verified its effectiveness via animal experiments.
OBJECTIVE: To investigate the effectiveness of a T-shaped magnet system for establishing a TEF model in beagle dogs.
METHODS: Twelve beagles were randomly assigned to groups in which magnets of the T-shaped scheme (study group, n = 6) or normal magnets (control group, n = 6) were implanted into the trachea and esophagus separately under gastroscopy. Operation time, operation success rate, and accidental injury were recorded. After operation, the presence and timing of cough and the time of magnet shedding were observed. Dogs in the control group were euthanized after X-ray and gastroscopy to confirm establishment of TEFs after coughing, and gross specimens of TEFs were obtained. Dogs in the study group were euthanized after X-ray and gastroscopy 2 wk after surgery, and gross specimens were obtained. Fistula size was measured in all animals, and then harvested fistula specimens were examined by hematoxylin and eosin (HE) and Masson trichrome staining.
RESULTS: The operation success rate was 100% for both groups. Operation time did not differ between the study group (5.25 min ± 1.29 min) and the control group (4.75 min ± 1.70 min; P = 0.331). No bleeding, perforation, or unplanned magnet attraction occurred in any animal during the operation. In the early postoperative period, all dogs ate freely and were generally in good condition. Dogs in the control group had severe cough after drinking water at 6-9 d after surgery. X-ray indicated that the magnets had entered the stomach, and gastroscopy showed TEF formation. Gross specimens of TEFs from the control group showed the formation of fistulas with a diameter of 4.94 mm ± 1.29 mm (range, 3.52-6.56 mm). HE and Masson trichrome staining showed scar tissue formation and hierarchical structural disorder at the fistulas. Dogs in the study group did not exhibit obvious coughing after surgery. X-ray examination 2 wk after surgery indicated fixed magnet positioning, and gastroscopy showed no change in magnet positioning. The magnets were removed using a snare under endoscopy, and TEF was observed. Gross specimens showed well-formed fistulas with a diameter of 6.11 mm ± 0.16 mm (range, 5.92-6.36 mm), which exceeded that in the control group (P < 0.001). Scar formation was observed on the internal surface of fistulas by HE and Masson trichrome staining, and the structure was more regular than that in the control group.
CONCLUSIONS: Use of the modified T-shaped magnet scheme is safe and feasible for establishing TEF and can achieve a more stable and uniform fistula size compared with ordinary magnets. Most importantly, this model offers better controllability, which improves the flexibility of follow-up studies.