Inflammatory Cytokine Responses to Synthetic Extracellular Matrix Injection to the Vocal Fold Lamina Propria

OBJECTIVES: We determined cytokine profiles for tumor necrosis factor alpha (TNF-alpha), interleukin (IL)-6, IL-1alpha, and IL-1beta after injection of a synthetic extracellular matrix into the vocal fold lamina propria. METHODS: Transcript expression of inflammatory cytokines was measured with real-time polymerase chain reaction on postoperative days 1, 3, 5, 10, and 21 in 25 rabbits that underwent bilateral vocal fold biopsy with Extracel-LG (Carbylan-GSX 5%) immediately injected into the wound in the left vocal fold and saline solution injected into the wound in the right vocal fold. Two unwounded normal rabbit larynges were also harvested for controls. RESULTS: Significantly elevated levels of TNF-alpha, IL-1beta, and IL-6 were measured on day 3 in a comparison between Extracel-LG-injected vocal folds and saline solution-injected control vocal folds and between Extracel-LG-injected vocal folds and normal vocal folds. All cytokine levels returned to baseline by day 21. CONCLUSIONS: A mild short-term inflammatory response was measured early after injection of a synthetic extracellular matrix into the vocal fold lamina propria.