Fibronectin and adhesion molecules on canine scarred vocal folds

To examine the expressions of fibronectin and other adhesion molecules on the scarred vocal folds in a short- and long-term animal model.

Animal model.

Six beagles' vocal folds were stripped unilaterally and left untreated. After wounding the vocal folds were harvested from three dogs at 2 months and three dogs at 6 months. The untouched vocal fold was used as a control, and the stripped vocal fold as scarred. Subsequently, the expressions of fibronectin, cadherin, syndecan-1 and syndecan-4 on both vocal folds were examined by immunohistochemical and image analysis.

Compared with the control vocal folds, fibronectin significantly increased in the superficial layer of the lamina propria on the scarred vocal folds at both 2 and 6 months. Co-deposition of collagen was observed only at 6 months. Syndecan-4 was significantly overexpressed at the basal layer cells of the epithelium at both 2 and 6 months. No significant expression of either cadherin or syndecan-1 was detected.

Scar characteristics at 2 and 6 months are not identical, suggesting that a 2-month period may not be a sufficient to study vocal fold scarring. Adhesion molecules are important in reorganization of extracellular matrix during wound healing because of their binding and adhesion characteristics. The results indicate that fibronectin might be important in providing a scaffold for the deposition of other proteins such as collagen, and the binding characteristics might affect the stiffness of the scarred vocal fold. Prolonged expression of syndecan-4 may reflect the role of focal adhesion during the assembly of scar structure. Ultimately, better understanding of the histological features of the scarred vocal fold might lead to new approaches to treatment.