Cellular and Tissue Mechanisms of Laser-Assisted Regeneration of Tympanic Membrane Perforation.

Chronic tympanic membrane (TM) perforations remain a significant clinical problem due to limited spontaneous healing and the drawbacks of surgical interventions. The present study aimed to evaluate the effects of low-intensity infrared laser irradiation on cellular mechanisms of regeneration and to assess its therapeutic potential in TM repair. Primary fibroblast cultures isolated from chinchilla tissue were exposed to laser radiation at wavelengths 1560 nm and 1450 nm. Cellular responses were analyzed using MTT assay, scratch test, Ki-67 immunostaining, and ELISA for collagen type II. In addition, an in vivo model of chronic TM perforation in chinchillas was used to validate the regenerative effects under physiological conditions. Laser irradiation was associated with accelerated scratch closure and increased extracellular matrix production under selected irradiation conditions, whereas metabolic and proliferative indices decreased over time, most likely reflecting culture confluence and maturation rather than cytotoxicity. In vivo, complete closure of tympanic membrane perforations was observed in all laser-treated ears in the context of collagen sponge-assisted repair, whereas scaffold-only control perforations remained unclosed. These findings support the potential of low-intensity infrared laser irradiation as a minimally invasive adjunct to scaffold-assisted tympanic membrane repair. However, the proposed involvement of endogenous progenitor cell populations should be regarded as a hypothesis requiring further histological and marker-based validation.