Scaffolds for Tympanic Membrane Regeneration in Rats

Tympanic membrane (TM) perforations lead to significant hearing loss and result in possible infection of the middle ear. Myringoplasty is commonly performed to repair chronic perforations. Although various grafts and materials have been used to promote TM regeneration, all have associated limitations. The aim of this study was to evaluate the efficacy and feasibility of two graft materials, silk fibroin scaffold (SFS) and porcine-derived acellular collagen type I/III scaffold (ACS), compared with two commonly used graft materials (paper patch and Gelfoam) for the promotion of TM regeneration. These scaffolds were implanted using on-lay myringoplasty in an acute TM perforation rat model. Surface morphology of the scaffolds was observed with scanning electron microscopy. The morphology of the TM was assessed at various time points postimplantation using otoscopy, light and electron microscopy, and functional outcomes by auditory brainstem responses. We found that SFS and ACS significantly accelerated the TM perforation closure, obtained optimal TM thickness, and resulted in better trilaminar morphology with well-organized collagen fibers and early restoration of hearing. However, paper patch and Gelfoam lost their scaffold function in the early stages and showed an inflammatory response, which may have contributed to delayed healing. This study indicates that compared with paper patch and Gelfoam, SFS and ACS are more effective in promoting an early TM regeneration and an improved hearing, suggesting that these scaffolds may be potential substitutes for clinical use.