Bone Resorption Factors in Chronic Otitis Media

Abstract

Collagenase was identified within naturally occurring rat chronic otitis media by the use of an immunohistochemical technique with peroxidase-antiperoxidase to stain the paraffin. Collagenase was found in fibroblasts, mononuclear cells, and osteoclast cells in the bone-resorbing area. Collagenase was found only in fibroblasts in contact with epithelial basal cells. Macrophages from rat peritoneum were cultured with different concentrations of a lipopolysaccharide. The prostaglandin E₂ level reached a maximum during the 12-to 24-hour period in the presence of endotoxin. This prostaglandin E₂ was confirmed by immunofluorescent staining. The endotoxin-activated macrophage produced an insignificant amount of collagenase. These findings suggest that activated macrophages may be able to stimulate fibroblast collagenase production through the chemical mediator prostaglandin E₂. Also, the interaction between fibroblasts and epidermal cells appears to encourage and enhance the biochemical events resulting in bone resorption in chronic otitis media.