Activation of the transforming growth factor beta pathway in bacterial otitis media.

Objectives: Granulation tissue is common in otitis media (OM), yet little is known about the signaling pathways in the formation of granulation tissue in response to infections. In this study, we sought to investigate the activation of the transforming growth factor beta (TGF-beta) signaling pathway in the formation of granulation tissue in response to middle ear pathogens.

Methods: Rat OM models were made by inoculating pneumococcus type 6A or nontypeable Haemophilus influenzae into the middle ear cavity or by obstructing the eustachian tube.