Pattern changes of mucin gene expression with pneumococcal otitis media

Objective: mucins, known to be important components of the mucociliary tran sport system in the middle ear and Eustachian tube, are subject to changes under inflammatory conditions. Which mucin genes are up-regulated or activa ted during an inflammatory reaction of the middle ear and Eustachian tube, however, is poorly understood. The purpose of this study was to characteriz e mucin gene expression in middle ears and Eustachian tubes with pneumococc al ear infection. Methods: sixteen rats received intrabullar inoculation of Streptococcus pneumoniae type 6A at 2,5 x 10(6) colony forming units (CFU) . Four animals were sacrificed on days 1, 3, 7, and 14, respectively. The p rofile of mucin gene expression in the middle car and Eustachian tube was e xamined by reverse transcription polymerase chain reaction (RT-PCR) at the above time points. Sixteen rats that received intrabullar inoculation of ph osphate-buffered saline (PBS) served as controls. Results: the Muc2 mucin g ene was expressed in middle ear mucosa of the control rats. Following pneum ococcal inoculation, Muc1-Muc-5 mucin genes were expressed in the middle ea r mucosa in a time-dependent manner. In the Eustachian tube. the Muc2, Muc4 and Muc5 mucin genes were expressed in both control and pneumococcal inocu lation groups. Conclusion: Muc1, Muc3, Muc4, and Muc5 mucin genes were acti vated in the middle ear mucosa by pneumococci, which may contribute to hype r-production of mucin in acute pneumococcal otitis media. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.