Pulse Steroid Therapy Inhibits Murine Subglottic Granulation

Abstract

Objective Using a functional model of airway granulation tissue in subglottic stenosis, we investigated changes in inflammatory markers within granulation tissue in response to intraperitoneal dexamethasone injections. Changes in inflammatory markers will allow us to identify potential targets for immunological therapy. Study Design Institutional Animal Care and Use Committee–approved animal study. Setting Philadelphia Veterans Administration Medical Center animal research facility. Subjects and Methods Laryngotracheal complexes of donor mice underwent direct airway injury and were transplanted into subcutaneous tissue of 19 recipient mice in 2 groups: steroid treated and untreated, with sample sizes of 10 and 9, respectively. The steroid-treated arm received intraperitoneal injection of dexamethasone for 3 weeks. Laryngotracheal complexes were then harvested, and granulation formation was measured. The messenger RNA (mRNA) expression of transforming growth factor (TGF)–β1 and interleukin (IL)–1 was quantified. Results At 3 weeks posttransplantation, there were statistically significant differences in observable granulation formation as well as mRNA expression of TGF-β1 and IL-1β in all groups within the steroid treated arm as compared with the untreated arm. Conclusions Systemic steroids have been used to prevent formation of granulation tissue and subglottic stenosis. However, the study of the immunologic markers and the corresponding changes with steroid treatment has not been well studied in animal models. Using a previously described novel murine model, we begin to delineate inflammatory markers that can be applied for potential therapeutic targets.