Tympanic membrane metalloproteinase inflammatory response.

Abstract

The goal of this study was to determine whether expression of matrix metalloproteinases (MMP) in tympanic membranes (TM) is stimulated by host tumor necrosis factor-alpha (TNF-alpha) and bacterial toxin (lipopolysaccharide, LPS), which may play a role in the pathogenesis of cholesteatoma. Gerbil TMs (n = 48) were cultured in the presence of either TNF-alpha or LPS. Quantitative analysis of TNF-alpha and MMPs was performed on both the homogenized TMs and the culture media supernatant. Levels of TNF-alpha and MMPs did not increase significantly in TMs with exposure to inflammatory mediators. TNF-alpha levels in supernatant were elevated (P < 0.007) with more concentrated LPS exposure. Supernatant levels of MMP2 were increased (P < 0.007) at most concentrations of LPS and TNF-alpha. Cultured TMs expressed MMPs in response to bacterial and host inflammatory mediators. These findings support a link between inflammation and the secretion of potentially destructive MMPs in the TM, which may contribute to the pathogenesis of cholesteatoma.