A novel murine model for the examination of experimental subglottic stenosis

Abstract

Objective: To develop a novel mouse model of acquired subglottic stenosis (SGS) using heterotopic transplanted laryngotracheal complexes (LTCs).

Design: Pilot randomized controlled animal study.

Subjects: Forty-eight C57BL/6 mice.

Interventions: Twenty-four donor C57BL/6 mice underwent LTC harvesting. The LTCs were then implanted deep to a cutaneous dorsal flap in 24 allogenic recipients. Sixteen LTCs underwent direct subglottic injury before transplantation, while 8 control LTCs were transplanted without injury. Transplanted LTCs were harvested 1, 2, 3, and 4 weeks after surgery. Tissues were fixed and cut transversely in 6-microm sections from the larynx to the second tracheal ring. Movat pentachrome staining was performed for connective tissue and morphometric analysis. Digital images of the subglottis were captured at x 20 magnification. The thicknesses of the lamina propria and the epithelium were measured at 5 random and equally spaced locations within the subglottic lumen. Vascular endothelial growth factor 164 (VEGF 164) and transforming growth factor beta1 (TGF-beta1) immunohistochemistry was performed on representative sections.

Results: Lamina propria thickness was significantly greater in transplanted LTCs 3 and 4 weeks after injury compared with controls (P = .03, P = .01, respectively). Combined results (groups harvested at 1-4 weeks) revealed a significant difference between all 8 control animals and all 16 experimental animals (P < .001). Epithelial thickness was also greater in the transplanted LTCs 2, 3, and 4 weeks after injury to the subglottis compared with controls (P = .04 for weeks 2 through 4). Movat pentachrome staining showed random distributions and high concentrations of connective tissue within the lamina propria of the subglottis. The VEGF 164 and TGF-beta1 staining patterns were consistent with previous in vivo models of SGS.

Conclusion: Heterotopic transplanted LTCs in mice can provide an inexpensive and flexible model for experimental investigation of acquired SGS.