Objective: To detect the expression and distribution of metallothionein 2 (MT-2) in middle ear cholesteatoma, and to explore the relationship of MT-2 with interleukin 1α (IL-1α) and interleukin 6 (IL-6), and well as to explore the role of MT-2 in the pathogenetic mechanism of middle ear cholesteatoma.
Methods: Using the immunohistochemistry and reverse transcription polymerase chain reaction to examine the expressions of MT-2, IL-1α and IL-6 protein and MT-2 mRNA in twenty-five middle ears' cholesteatoma and seven normal external ears' canal skin. The influence of cholesteatoma debris on the MT-2 mRNA and protein of HaCaT cell were further analyzed.
Results: According to immunohistochemistry research, the expressions of MT-2, IL-1α and IL-6 were extremely higher in middle ear cholesteatoma than those in normal external ears' canal skin (P < 0.05). The result of RT-PCR showed that there was significant difference between the expression of MT-2 mRNA of and middle ear cholesteatoma than those in normal external ear canal skin (t = 15.38, P < 0.05). There was a positive correlation between the expression of MT-2 and that of IL-1α (r = 0.856, P < 0.05). There was also positive correlation between the expression of MT-2 and that of IL-6 (r = 0.714, P < 0.05). MT-2 mRNA and protein of HaCaT cell significantly increased when exposed to cholesteatoma debris in a dose dependent manner.
Conclusions: MT-2, IL-1α and IL-6 may play an important role in the pathogenetic process of middle ear cholesteatoma. Cholesteatoma debris may involve in the proliferation of middle ear cholesteatoma by activation of MT-2.