A novel rat model for tracheal mucosal damage assessment of following long term intubation

Objective: Tracheal mucosal damage is a well-known complication of endo-tracheal intubation and animal models are essential for studying the underlying cellular injury cascade. The novel rat model described here is based on retrograde intubation via tracheotomy and suture fixation of the tube. It aims to simulate the common clinical scenario of tube-related airway damage due to long term intubation. Study design: Prospective randomized control pilot study. Methods: Male Sprague-Dawley were randomly assigned into two groups: control (no intubation, n = 10), one week of intubation (n = 13). The animals were then euthanized and the trachea was sent for histological analysis. Epithelial damage, mucosal thickness, mucosal gland hypertrophy and fibrosis were reviewed. Results: Intubation procedure survival rate was 84.6% (11/13) and 100% in the control (10/10). The damaged ciliary mechanism was a common finding in the intubated group compared to the preserved normal ciliary architecture in almost all control rats. Average tracheal mucosal thickness was 119.0 ± 21.8 μm for the control group and 254.6 ± 22.8 μm for the intubated group, (p < 0.001). The ciliary damage score was 1.00 ± 0.02 in the intubated group, and 0 ± 0.02 in the control group. (p < 0.001). The (objective) average total tracheal mucosal gland area was 19,530 ± 24,606 in the intubated group and 10,031 ± 23,461 in the control group (p < 0,05). Collagen deposition seems higher in the intubated trachea compared to the control. Conclusions: We describe a novel rat-based animal model for simulating tracheal mucosal damage following long term intubation. This animal model is easy to carry out, reproducible and involves containable animal mortality rates. Level of evidence: I.