Epithelial response to vocal fold microflap injury in a preclinical model.

Objectives: Functional outcomes following microflap surgery for vocal fold pathology are favorable. Although the stratified squamous epithelium appears to heal rapidly, persistent physiologic tissue alterations are likely. We sought to elucidate key biochemical processes including recruitment of immune cells, regulation of cellular junction proteins, and long-term alterations to epithelial tissue permeability following microflap with an eye toward enhanced clinical outcomes.

Methods: Forty New Zealand rabbits were assigned to eight groups (n = 5/group): no-injury control or bilateral microflap with survival for 0 h, 12 h, 1 day, 3 days, 7 days, 30 days, and 60 days post-microflap. The epithelium was dissected from one vocal fold and transepithelial resistance was quantified. The contralateral fold was subjected to transmission electron microscopy. Images were evaluated by a blinded rater and paracellular space dilation was quantified using ImageJ. Immune cell infiltration was evaluated and recorded qualitatively.

Results: Increased innate immune response was observed 12 h as well as 7 and 30 days after microflap. At 60 days following injury, decreased epithelial resistance was observed. Paracellular spaces were dilated at all time-points following injury.

Conclusions: The vocal fold epithelium was significantly altered at 60 days following microflap. The implications for this tissue phenotype are unclear. However, compromised epithelial barrier function is implicated in various diseases and may increase the risk of subsequent injury.

Level Of Evidence: NA Laryngoscope, 133:350-356, 2023.