OBJECTIVETo investigate the differential expression of toll-like receptor 2 (TLR2), toll-like receptor 4 (TLR4) and their potential role in the pathogenesis of chronic suppurative otitis media and cholesteatoma.

METHODSNormal canal skin of 30 patients with tympanosclerosis were enrolled as control, 30 cases with chronic suppurative otitis media and 30 patients with cholesteatoma were studied. Real-time PCR, Western blot and Immunohistochemistry were preformed to detect the expression of TLR2/TLR4 in normal canal skin, mucosa and granulation tissue of chronic suppurative otitis media, mucosa, granulation tissue, cholesteatoma epithelium of cholesteatoma, and the differential expression were analyzed.

RESULTS(1) the mRNA and protein expression of TLR2 and TLR4 were detected in all normal canal skin, mucosa and granulation tissue of chronic suppurative otitis media, mucosa, granulation tissue, cholesteatoma epithelium of cholesteatoma. (2) Both mRNA and protein level of TLR2/TLR4 in mucosa of chronic suppurative otitis media and cholesteatoma were higher than those in normal canal skin, but lower in cholesteatoma epithelium, there was no significant difference in mucosa of the two otitis media groups. (3) The mRNA and protein expression of TLR2/TLR4 in granulation tissue of chronic suppurative otitis media and cholesteatoma were significant increased when compared with normal canal skin, and TLR2 expression level was higher in granulation tissue of cholesteatoma than in chronic suppurative otitis media. (4) TLR2/TLR4 positive cells mainly infiltrated in granulations, significantly more than in normal skin, while fewer in the epithelium of cholesteatoma.

CONCLUSIONSDifferential expression of TLR2 and TLR4 in mucosa suggests middle ear is a TLR2/TLR4 participated functional modulation of the innate immune system and also suggests that they may play a different role in the pathophysiology of chronic otitis media and cholesteatoma.