TNF and otitis media with effusion: The mice were kept for an additional 3 weeks (4 weeks after LPS) and examined for the recruitment of inflammatory cells and macrophage polarization in OME, the levels of major pro-inflammatory cytokines IL-1β, IL-6, TNFα and IFNɣ in mouse OME, as well as the levels of ROS, MDA, GSH and SOD in the middle ear mucosae tissue.