Elucidating the Role of Interleukin 1β and Prostaglandin E2 in Upper Airway Mucosal Wound Healing

Abstract

To determine whether (1) inflammatory mediators IL-1beta (interleukin 1beta) and prostaglandin E2 (PGE2) in mucosal secretions correlate with subglottic mucosal injury; and (2) mucosal fibroblasts contribute to PGE2 production during mucosal healing. The subglottic mucosa in rabbits was wounded by means of varied carbon dioxide laser power and duration. Subglottic fibroblasts were exposed to IL-1beta and assayed for production of PGE2. Thirty-eight New Zealand white rabbits were used. Fibroblasts from normal and pathologic human subglottic tissues were grown in culture. Subglottic injury was established in 29 rabbits, and 9 rabbits were sham-wounded. Subglottic mucosal secretions were collected at baseline and days 1, 3, 7, 14, and 21 postoperatively and assayed for IL-1beta and PGE2 by enzyme-linked immunosorbent assay. Tissue was analyzed using quantitative polymerase chain reaction. Fibroblast cultures were exposed to IL-1beta and analyzed for PGE2 and its synthetic enzymes. Subglottic injury was associated with increased levels of IL-1beta and PGE2 in secretions. More extensive mucosal injury resulted in higher PGE2 levels at earlier times. Levels of IL-1beta were maximal after lesser damage. Expression of IL-beta and cyclo-oxygenase 2 was elevated after mucosal injury. Fibroblast treatment with IL-1beta resulted in translocation of nuclear factor kappaB, up-regulation of PGE2 synthetic enzymes, and increased production of endogenous PGE2. Mucosal injury is associated with up-regulation of inflammatory genes and parallel increases in secretion levels of IL-1beta and PGE2, key mediators of inflammation and healing. Subglottic mucosal fibroblasts are a potential source of inflammatory mediators after injury or other trauma.