可降解复合人工食管重建犬颈段食管的实验研究

目的 采用生物可降解材料与非降解材料复合制成人工食管，诱导自身食管组织爬行再生与生物材料降解相匹配，最终再生食管完全替代人工食管。方法 将长50mm、内径20mm的医用聚氨酯内管表面覆盖海绵状胶原蛋白壳聚糖膜，体外制成人工食管，通过手术替换Ⅰ组(5只犬)和Ⅱ组(10只犬)颈段5cm食管缺损，术后给予营养支持，禁食2周或4周后通过内镜分别取出Ⅰ、Ⅱ组聚氨酯内管，通过组织学及电镜等检测、观察新生食管上皮化过程。结果 禁食2周后取出I组聚氨酯内管的5只实验犬，新生食管上皮再生不完全；术后4周内均出现进行性狭窄无法吞咽，致全身衰竭死亡。Ⅱ组禁食4周后取出聚氨酯内管的10只实验犬，新生食管完全上皮化；12周时黏膜全层结构完整再生；24周时食管肌层部分再生，有3只犬生存8个月以上。结论 由聚氨酯内管提供暂时通道和支撑，海绵状胶原蛋白壳聚糖膜提供适宜细胞爬行再生的三维支架，维持4周的降解时间能够重建犬颈段5cm长食管缺损。

RECONSTRUCTION OF A CERVICAL ESOPHAGUS SEGMENT WITH AN ARTIFICIAL PROSTHESIS BY USE OF A POLYURETHANE STENT COVERED WITH COLLAGEN-CHITOSAN SPONGE IN DOGS

OBJECTIVE: To repair esophageal defects with an artificial prosthesis composed of biodegradable materials and nonbiodegradable materials, which is gradually replaced by host tissue. METHODS: The artificial esophagus was a two-layer tube consisting of a chitosan-collagen sponge and an inner polyurethane stent with a diameter of 20 mm and a length of 50 mm. We used the artificial esophagus to replace 5 cm esophageal defects in group I (five dogs) and in group II (ten dogs), and nutritional support was given after operation. The inner polyurethane stent was removed after 2 weeks in group I and after 4 weeks in group II endoscopically and epithelization of the regenerated esophagus was observed by histologic examination and transmission electron microscope. RESULTS: In group I, the polyurethane stent was removed after 2 weeks, and partial regeneration of esophageal epithelial was observed; and constriction of the regenerated esophagus progressed and the dogs became unable to swallow after 4 weeks. In group II, the polyurethane stent was removed after 4 weeks, highly regenerated esophageal tissue successfully replaced the defect and complete epithelization of the regenerated esophagus was observed. After 12 weeks, complete regeneration of esophageal mucosa structures, including mucosal smooth muscle and mucosal glands and partial regeneration of esophageal muscle tissue were observed. CONCLUSION: Esophageal high-order structures can be regenerated and provided a temporary stent and support by polyurethane stent and an adequate three-dimensional structure for 4 weeks by collagen-chitosan sponge.