OBJECTIVETo explore the expression and activation of NF-kappaB in middle ear cholesteatoma.

METHODSThe protein expression of NF-kappaB p65 in 21 middle ear cholesteatoma tissues and 8 normal external ear canal skin obtained in middle ear surgery were examined by immunohistochemistry; NF-kappaB DNA binding activity in these two kinds of tissues were also detected by electrophoretic motility shift assay (EMSA). The influence of cholesteatoma debris on the NF-kappaB DNA binding activity of HaCat cell were further analyzed.

RESULTSAll epithelial cell of cholesteatoma revealed a relatively abundant plasma expression of NF-kappaB p65 protein, among which 12 cases showed nuclear positive expression. In contrast,the normal skin epithelium only revealed a sparse plasma distribution of NF-kappaB protein. The levels of NF-kappaB p65 protein expression in the epithelium of middle ear cholesteatoma tissue and normal skin were 0.168 +/- 0.051, 0.088 +/- 0.019 (t = 4.211, P < 0.01), respectively. The NF-kappaB DNA binding activities of cholesteatoma [(16.5 +/- 10.1)%] were also higher than those in normal skin [(1.38 +/- 1.24)%, t = 3. 600, P = 0.014]. The NF-kappaB DNA binding activity of HaCat cell increased when exposed to cholesteatoma debris in a dose dependent manner.

CONCLUSIONNF-kappaB might be an important factor which was involved in the occurrence and development of cholesteatoma.