Study on in vivo and in vitro degradation of polydioxanone weaving tracheal stents

Abstract The appropriate degradation characteristics of polydioxanone (PDO) are necessary for the safety and effectiveness of stents. This study aimed to investigate the degradation of PDO weaving tracheal stents (PW stents) in vitro and in vivo. The degradation solution of S. aureus (SAU), E. coli (ECO), P. aeruginosa (PAE), and control (N) were prepared, and the PW stents were immersed for 12 weeks. Then, the radial support force, weight retention, pH, molecular structure, thermal performance, and morphology were determined. Furthermore, the PW stents were implanted into the abdominal cavity of rabbits, and omentum was embedded. At feeding for 16 weeks, the mechanical properties, and morphology were measured. During the first 8 weeks, the radial support force in all groups was progressively decreased. At week 2, the decline rate of radial support force in the experimental groups was significantly faster compared to the N group, and the difference was narrowed thereafter. The infrared spectrum showed that during the whole degradation process, SAU, ECO and PAE solution did not lead to the formation of new functional groups in PW stents. In vitro scanning electron microscope observation showed that SAU and ECO were more likely to gather and multiply at the weaving points of the PW stents, forming colonies. In vivo experiments showed that the degradation in the concavity of weaving points of PW stents was more rapid and severe. The radial support loss rate reached more than 70% at week 4, and the radial support force was no longer measurable after week 8. In omentum, multinuclear giant cells and foreign giant cells were found to infiltrate. PW stents have good biocompatibility. The degradation rate of PW stents in the aseptic conditions in vivo was faster than in the bacteriological environment in vitro.