Clinical, Histological, and Profibrotic Extracellular Matrix Protein Changes in a Model of Tracheal Stenosis Induced by Cervical Tracheal Autotransplantation

Abstract

Background

Tracheal stenosis (TS) is a complication of prolonged intubation, tracheotomy, and tracheal surgery that compromises the vascular supply. Animal models are essential for studying its pathophysiology and the effect of interventions.

Objective

To establish a TS model in rats secondary to tracheal autotransplantation with a graft submerged in bleomycin (Atx-Bleo). Additionally, to evaluate the clinical and histological changes, as well as the expression of newly formed collagen (NFC), isoforms of transforming growth factor beta (TGFβ), fibronectin (FN), elastin (ELN), integrin β1 (ITGβ1), and matrix metalloproteinase 1 (MMP1) in TS.

Methods

Twenty Wistar rats were divided into three groups: group I (n = 20) control; group II (n = 10) end-to-end anastomosis of the trachea (tracheoplasty); and group III (n = 10) Atx-Bleo. The animals were evaluated clinically, tomographically, macroscopically, morphometrically, and microscopically. NFC deposition, and the expression of profibrotic and antifibrotic proteins were evaluated in tracheal scars.

Results

All animals survived the surgical procedure and the study period. Compared with the other study groups, the Atx-Bleo group developed TS and fibrosis, exhibited higher expression of NFC, TGFβ1, TGFβ2, FN, ELN, and ITGβ1, and mild expression of TGFβ3 and MMP1 (p < 0.005; analysis of variance, Dunnett and Tukey tests).

Conclusion

Atx-Bleo in TS model rats produces tomographic and histological changes, and induces the upregulation of profibrotic proteins (TGFβ1, TGFβ2, collagen, FN, ELN, ITGβ1) and downregulation of antifibrotic proteins (TGFβ3, MMP1). Therefore, this model may be used to test new pharmacological treatments for reversing or preventing TS, and conduct basic studies regarding its pathophysiology.

Keywords:

• Tracheal stenosis
• animal model
• bleomycin
• TGFβ
• extracellular matrix protein

Acknowledgements

The authors want to thank: Roberto Rueda, Sergio Martínez, Guadalupe Hiriart, Erica Monterrubio and radiology technical staff for their invaluable technical assistance and support with the animals, histological preparations and obtaining the tomographic studies.

Author contributions

MSM, JROZ and JC. Investigation, conceptualization and design of the work. MSM, JROZ, JC, ANA, LPP, FJH, RSR, RJV JCVM designed and conducted the experimental model. MSM, JC, MBL, MGG, ANA, ALF designed and conducted the laboratory studies. MSM, JROZ, acquisition, interpretation of data and drafting the work. All authors reviewed and approved the final version.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Institute of Respiratory Diseases “Ismael Cosio Villegas.” The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.