A Novel Mouse Model Of Otitis Media Induced By Streptococcal Peptidoglycan-Polysaccharide In Toll-like Receptor 2 Deficient Mice For Testing Drug Efficacy

Toll-like receptor 2 (TLR2) deficiency is associated with the development of chronic suppurative otitis media (CSOM) in humans and persistent presence of streptococcal peptidoglycan-polysaccharide (PGPS) in the middle ears (MEs) can cause chronic otitis media (COM). Here, we report a new model of otitis media (OM) in Toll-like receptor 2 deficient (Tlr2-/-) mice following PGPS challenge. Intriguingly, inoculation of the right MEs with PGPS induced bilateral OM in mice. In comparison to wide-type (WT) mice, the Tlr2-/- mice were more susceptible to PGPS-induced OM and displayed persistently severe neutrophil infiltration in the tympanic cavity. Furthermore, increased levels of oxidative stress-related gene expression, but decreased levels of cytokine and mucin expression were detected in Tlr2-/- mice. Treatment with sodium aescinate (SA) effectively ameliorated inflammation and oxidative stress, and improved hearing and ciliary movement function in the MEs of Tlr2-/- mice, which may be associated with enhancing the glucocorticoid-related signaling. Thus, this new model of OM had unique pathophysiological features and treatment with SA effectively inhibited inflammation and improved hearing function in OM mice.