Collagenase activity in cholesteatoma.

Collagenase activity of cholesteatoma epithelium, temporal bone and ear canal skin was investigated. The enzyme extracted from these tissues was proved to be collagenase by disc electrophoresis. Collagenase activity was measured directly in homogenates of tissues. Activity was greatest in the skin. The activity in cholesteatomas was either higher than that of the bone, or the activity was higher in bone than in the cholesteatoma. These findings suggest that some variation of collagenase activity may be due to the stage of cholesteatoma, active or inactive in collagen metabolism of bone destruction, and that the ear canal skin plays a great role in bone destruction, this supporting the immigration theory.