Immunohistochemical Study of Transforming Growth Factor-α Expression in Normal and Perforated Tympanic Membrane

An immunohistochemical study of transforming growth factor-α (TGF-α) distribution was carried out to clarify the mechanism responsible for accelerated epidermal cell proliferation after perforation of the rabbit tympanic membrane. In the normal tympanic membrane, TGF-α expression was not observed, whereas after perforation, over the whole tympanic membrane including the margin of the perforation, TGF-α-positive cells appeared and were scattered in the epidermal cell layer. After healing of the perforation, a marked decrease of TGF-α-positive cells in the tympanic membrane was observed. This finding suggests that TGF-α induces proliferation of epidermal cells after the perforation stimulus.