Investigating the acute effects of acrolein on ion transport and mucin gene expression in excised porcine vocal folds

Elizabeth Felicia Levendoski, Purdue University

Abstract

The epithelial surfaces of the larynx are covered by a thin layer of mucus. This mucus is critical for both laryngeal defense and voice production. There is emerging evidence that chronic pollutant exposure alters the physical properties of the mucus that covers the laryngeal surfaces. Using an in vitro porcine model, this study sought to investigate biological mechanisms that potentially underlie pollutant-induced disruptions in laryngeal mucus. Specifically, this study examined the effects of an acute, high concentration exposure to the pollutant, acrolein, on epithelial ion transport and mucin gene expression, both functional mechanisms critical to maintenance of the mucus layer. Epithelial ion transport was assessed in the true vocal folds, while mucin gene expression was assessed in both the true and the false vocal folds. We tested the hypothesis that a short duration acrolein challenge would decrease epithelial ion transport and increase mucin gene expression. Given the significant cytotoxicity of acrolein and the high concentration used, this study further sought to explore the effects of acrolein on vocal fold epithelial functional and structural integrity. It was hypothesized that the epithelium of acrolein challenged-vocal folds would demonstrate some early signs of injury. To test these hypotheses, freshly excised porcine vocal folds (N=105) were exposed on the luminal surface to a short duration acrolein or sham challenge. Acrolein-induced alterations in epithelial ion transport, mucin gene expression, and vocal fold epithelial integrity were evaluated. We found that acrolein, but not sham challenges significantly reduced ion transport. Specifically, acrolein-induced reductions in ion transport were a function of impaired sodium absorption. No significant changes in mucin gene expression or epithelial integrity were observed following acrolein exposure. The results here contribute to our understanding of the acute effects of acrolein on vocal fold function and integrity as well as to the identification of early mechanisms that may contribute to pollutant-induced alterations in laryngeal mucus. Furthermore, these findings provide a foundation for the development of future investigations that seek to expand our understanding of the impact of pollutants on laryngeal health.

Degree

Ph.D.

Advisors

Sivasankar, Purdue University.

Subject Area

Genetics|Speech therapy

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