Date of Award

5-2018

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Health Sciences

Committee Chair

Wei Zheng

Committee Member 1

Preeti Sivasankar

Committee Member 2

Jennifer Freeman

Committee Member 3

Jason Cannon

Abstract

The vocal folds are located in the larynx and are responsible for voice production. The epithelium of the vocal folds is of the stratified squamous type. These epithelial cells along with the characteristic tight junctional complex create an active barrier, that protects the underlying connective tissue against air-borne xenobiotics. Damage to the epithelium can lead to penetration of xenobiotics and may cause inflammation in connective tissue. Particles and chemicals have different physical properties and have different capacities for penetrating epithelium and inducing inflammation in underlying tissues. In this study, we investigated the effects of one type of particle (single-walled carbon nanotubes) and one type of volatile chemical (acrolein) on vocal fold epithelium and connective tissue. The particle and the volatile chemical we choose represent common challenges in either the occupational environment or in daily life. We hypothesized that single-walled carbon nanotubes damage vocal fold epithelial barrier and promote fibrosis in connective tissue and that acrolein exposure impairs vocal fold epithelium and induces inflammation. In summary, the project (i) investigated the effects of nanoparticles on vocal fold epithelium and fibroblasts (Chapter 2), (ii) identified the damage from acrolein exposure on vocal fold epithelium and demonstrated the mechanism for this effect as lipid peroxidation induced cellular membrane damage (Chapter 3), (iii) identified the pathophysiological changes associated with sub-acute acrolein exposure in rat laryngeal epithelium and lamina propria (Chapter 4). Overall, the results suggest that acrolein exposure damages vocal fold epithelium and induces a proinflammatory reaction. The nanoparticles do not affect vocal fold epithelium but may have a fibrotic effect on vocal fold fibroblasts.

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