Conclusions: Bacterial OM triggers granulation tissue to thrive in the middle ear cleft of rats.

In ears with bacterial OM, the TGF-beta signaling pathway products were higher in Haemophilus-infected ears than in pneumococcus-infected ears.

Therefore, the combination of both approaches provides a powerful new means to explore the biological and biophysical behavior of the bacterial OM.

Results: The TGF-beta signaling pathway was highly regulated in the middle ear cleft with bacterial OM, but not in the ears with eustachian tube obstruction.