OBJECTIVETo establish the activation of NF-kappaB in middle ear cholesteatoma, discuss the relationship of NF-kappaB and the gene expression of IL-6 and explore the pathogenesis of middle ear cholesteatoma.

METHODSTen cases of cholesteatoma and 6 cases of normal external meatal skin were obtained from middle ear surgery. The NF-kappaB DNA binding activity and the mRNA level of IL-6 in these two kinds of tissues were detected by electrophoretic motility shift assay (EMSA) and Reverse transcription polymerase chain reaction (RT-PCR) respectively. The relationship of NF-kappaB DNA binding activity and the mRNA level of IL-6 were analyzed.

RESULTSThe NF-kappaB DNA binding activities of cholesteatoma [(15.9 +/- 8.2)%] were higher than those in normal skin [(1.36 +/- 0.94)%, t = 3.502, P < 0.05]. The expression of IL-6 mRNA was increased significantly in patients with cholesteatoma, as compared with that in the control specimens (t = 2.166, P < 0.05) and had a significant positive correlation with NF-kappaB DNA binding activity (r = 0.752, P < 0.05).

CONCLUSIONSThe IL-6 mRNA expression in cholesteatoma is closely related with the activity of NF-kappaB. It is tempting to speculate that NF-kappaB play a key role in the activation of cytokine in cholesteatoma.

Cholesteatoma, Middle Ear ; genetics ; metabolism ; Gene Expression Regulation ; Humans ; Interleukin-6 ; genetics ; metabolism ; NF-kappa B ; metabolism ; RNA, Messenger ; genetics

Transglutaminase (TGase) isoenzymes are involved in the process of the differentiation and cornification of keratinocytes in the epidermis. This study investigates the presence and localization of three TGase isoenzymes to elucidate the nature and differentiation status of the squamous epithelium in human aural cholesteatoma. Twenty cholesteatoma specimens were used. The presence and localization of three TGase isoenzymes were studied by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. mRNA expression of three TGase isoenzymes were detected in the tested cholesteatomas with variable levels. The immunohistochemical staining patterns of three TGase isoenzymes showed variations within specimens, relating to keratinizing activity. TGase K is the most abundant among three isoenzymes. Keratinizing epithelium of cholesteatoma have similar expression profiles of TGase isoenzymes with those of epidermis of the skin. Other areas, particularly those showing non-keratinizing epithelium, showed weak immunostaining of TGase E and C, suggesting its different maturation status from keratinizing epithelium. The results of this study indicate that epithelium of cholesteatoma undergoes same direction of maturation and differentiation characteristics as the epidermis of skin, evidenced by similar expressions of TGases both in mRNA level and immunohistochemistry.
Cell Differentiation ; Cholesteatoma, Middle Ear/genetics ; Cholesteatoma, Middle Ear/enzymology* ; Comparative Study ; Diagnosis, Differential ; Epidermis/enzymology ; Epithelial Cells/enzymology ; Human ; Immunohistochemistry ; Isoenzymes/metabolism ; Isoenzymes/genetics ; Keratinocytes/enzymology ; Protein-Glutamine gamma-Glutamyltransferase/metabolism* ; Protein-Glutamine gamma-Glutamyltransferase/genetics ; RNA, Messenger/metabolism ; Reverse Transcriptase Polymerase Chain Reaction