Histologic changes of mesenchymal stem cell repair of tympanic membrane perforation.

Conclusion: Mesenchymal stem-cells are good candidates for cell-therapy of chronic tympanic membranes perforations.

Objectives: To determine the effects of cell-based therapy in tympanic membrane perforations.

Methods: Young C57BL/6 mice were anesthetized with intraperitoneal administration of ketamine and xylazine and randomly divided into three groups (n = 4 ears/group) that underwent bilateral sub-total pars tensa perforations of equal sizes using a sterile 27-gauge needle under a surgical microscope. Six-to-eight hours after injury, one group of mice did not receive treatment (acute perforation control), and the last two groups were treated with BM-MSCs embedded within HA scaffolds previously soaked in PBS to rinse culture media residues to avoid confounders and were euthanized 1 or 2 weeks after treatment.

Results: Untreated tympanic membrane perforations developed a hyper-cellular infiltrate surrounding the injury site, while BM-MSC treated eardrums showed a reduced inflammatory response after the first week and a restoration of the trilaminar configuration 2 weeks after treatment, mimicking a normal tympanic membrane.