Liu Jin, Shang Liang, Liu Jiyong, Qin Chengyong
Department of Gastroenterology, Shandong Provincial Hospital Affiliated to Shandong University 324# Jingwu Road, Jinan, Shandong, China.
Department of General Surgery, Shandong Provincial Hospital Affiliated to Shandong University 324# Jingwu Road, Jinan, Shandong, China.
Am J Transl Res. 2016 Feb 15;8(2):1108-14. eCollection 2016.
Biodegradable esophageal stents eliminate stent retrieval, but usually induce hyperplasia. This study investigated the properties of a novel biodegradable stent in vitro and in vivo. The degradation of the novel stent was observed in phosphate buffered saline (PBS) for 8 weeks. The radial forces, pH values, morphology, and retention rate of the intrinsic viscosity (R[η]) of the new biodegradable stent were all evaluated. In vitro, the pH values remained constant for 4 weeks and declined from weeks 4 to 8. The biodegradable threads degraded and ruptured at 6 weeks. Consequently, the radial force of the stent decreased to zero at that time. The curve of R[η] decreased with time linearly in PBS. To study the stents in vivo, we used a stricture model in which the middle esophagus of rabbits was damaged by alkali burn. Stents were inserted 2 weeks after injury and observed for 8 weeks. We assessed complications related to stent insertion, degradation of the stent, and survival of the rabbits. Two stents migrated, and one rabbit died. In the other rabbits, two stents degraded and moved into the stomach during the sixth week, five during the seventh week and one during the eighth week, respectively. One stent remained in position until the end of the study. In conclusion, our newly designed stent retained the strong radial force of self-expandable metal stents (SEMSs) and maintained the biodegradable properties of biodegradable (BD) stents.
可生物降解食管支架无需取出支架，但通常会引发增生。本研究在体外和体内对一种新型可生物降解支架的特性进行了调查。在磷酸盐缓冲盐水（PBS）中观察新型支架8周的降解情况。对新型可生物降解支架的径向力、pH值、形态以及特性粘度保留率（R[η]）进行了评估。在体外，pH值在4周内保持恒定，从第4周开始下降至第8周。可生物降解丝线在6周时降解并断裂。因此，此时支架的径向力降至零。在PBS中，R[η]曲线随时间呈线性下降。为了在体内研究支架，我们使用了一个狭窄模型，其中兔食管中部被碱烧伤。在损伤2周后插入支架，并观察8周。我们评估了与支架插入、支架降解以及兔存活相关的并发症。两个支架移位，一只兔死亡。在其他兔中，两个支架分别在第6周、5个在第7周、1个在第8周降解并移入胃内。一个支架直至研究结束时仍保持在原位。总之，我们新设计的支架保留了自膨式金属支架（SEMSs）的强大径向力，并保持了可生物降解（BD）支架的可生物降解特性。
