Manuscript Title: Effects of Topical Mitomycin-C on the Tracheal Epithelia of Rabbits following Tracheostomy Running Title: Effects of Topical Mitomycin-C on the Tracheal Epithelia

Background and Aim: We aimed to investigate the topical application of mitomycin-C (MMC) after the conventional tracheostomy in a rabbit model. Materials and Methods: Twenty-four male New Zealand White rabbits were randomly divided among three equal groups (n: 8). Tracheostomies were performed on 16 subjects. Group 1 which served as a control for all tracheal measurements. After tracheostomy, we applied sterile saline (Group 2) or MMC at 0.8 mg/ml (Group 3) around the tracheotomy site for 5 min. At week three after surgery, all tracheas were subjected to morphometric and histopathological examinations, including tracheal lumen diameter (LD), number of capillary vessels (CV), subepithelial tissue thickness (SETT), fibroblasts, and inflammatory cells (IC). Results: There was a statistically significant difference between the two tracheostomy groups themselves and the control group for LD (P = 0.035), CV (P = 0.006), SETT, fibroblasts, and IC (P < 0.001). Histopathological analysis showed the decreased LD, CV, SETT, IC, and fibroblasts compared to MMC with tracheostomy groups. MMC was more effective than saline for LD, CV, SETT, IC, and fibroblasts. Conclusion: Wound healing modulation may prevent scar formation. Fibrosis decreased following tracheostomy in the group treated with MMC. Fibroblasts appear to be key cells mediating these effects.