The Role of Systemic Dehydration in Vocal Fold Healing

Systemic dehydration negatively alters epithelial cell junction markers and inflammatory mediators  in  vocal  fold  tissue.  In other  organs,  dehydration canhave the  following  suboptimal outcomes; prolonged inflammation and delayed re-epithelization.It is surprising that the adverse role  of  systemic  dehydration  in  vocal  fold  healing  has  not  been  directly  demonstrated  when dehydration has the potential to alter recovery following injury. The similarities between healing in dermal and mucosal tissue indicate an increased need to understand the effects of dehydration onvocal fold recovery.

Suboptimal vocal fold healing can have downstream consequences on vibratory function. Before functional voice changes can be delineated, there is a need to characterize the cellular interactions of  systemic  dehydration  and  vocal  fold  healing.   The  overarching  research  aim  of  this dissertation is to investigate the interaction of systemic dehydration and vocal fold healing on the gene expression of inflammatory and epithelial cell junction markers, following acute vocal  fold  injury.Gene expressionoutcomes werecompared  in four  groups;systemically-dehydrated,and  euhydrated  rats with minor,  bilateral  vocal  fold  injuriesand  systemically-dehydrated  and  euhydrated  rats  without  vocal  fold  injuries (N=9/group). We  hypothesized  that systemic  dehydration(compared  to  euhydration)would  cause an upregulation  of  pro  and  anti-inflammatory mediators with injury, but adownregulation of these inflammatory markers in the absence  of  injury.  We  also  hypothesized  that  systemic  dehydration(compared  to  euhydration)would cause a downregulation of epithelial cell junction markers with and without injury, butthat the effects of dehydration would be exacerbated with injury. 

We  found  that  the  gene  expression  of  pro-inflammatory  cytokines  was  differentially expressed  in  systemically-dehydrated  injured  vocal  old  tissue  when  compared  to  systemically-euhydrated injured vocal  fold  tissue, 24  hours  after  vocal  fold  injury. These  data  lay  the groundwork for future studies characterizing the later stages of interaction of systemic dehydration and injury.