Evaluation of Acellular Bilayer Silk Fibroin Grafts for Onlay Tracheoplasty in a Rat Defect Model.

Objective To assess the efficacy of acellular bilayer silk fibroin (BLSF) grafts to repair full-thickness tracheal defects and to compare the performance with conventional porcine small intestinal submucosa (SIS) implants. Study Design A prospective controlled animal trial in a rat model of onlay tracheoplasty. Setting Pediatric medical center. Subjects and Methods Tracheal reconstruction of adult Sprague-Dawley rats was performed with BLSF (n = 38) or SIS (n = 32) matrices for up to 3 months of implantation. Functional evaluations of repaired conduits as well as histologic, immunohistochemical, and histomorphometric analyses of neotissues were assessed. Results Prior to scheduled euthanasia, survival rates of rats receiving BLSF or SIS grafts were ≥94%, with no clinical signs of airway obstruction observed over the course of the study. Micro-computed tomography analysis revealed that the mean percentage of stenosis was <20% in both implant groups. BLSF and SIS grafts supported formation of pseudostratified ciliated columnar epithelium by 1 week postoperatively; however, each matrix failed to promote de novo chondrogenesis by 3 months following repair. Conclusions BLSF scaffolds can be used for reconstruction of rat tracheal patch defects with functional outcomes comparable to those of SIS matrices.