Role Of Autophagy Impairment In The Otitis Media Induced By Peptidoglycan-polysaccharide In TLR2-deficient Mice

Objective:This project explored the relationship between autophagy and the pathogenesis of otitis media by establishing a mouse model of otitis media,which may provide a theoretical basis for the clinical treatment of otitis media.Meanwhile,it searched for therapeutic targets and developed new drugs of otitis media,so as to improve otitis media by inducing autophagy.Methods:In early stage otitis media mice model,we selected TLR2 gene knockout(Tlr2-/-)mice to inject 60?g/10?l concentration of PGPS into the middle ear cavity through tympanocentesis,and successfully constructed a model similar to human otitis media.Normal wild-type(C57BL/6,C57)mice were used as the control group to induce otitis media at the same time,and follow-up experiments were conducted three days later.In the later stage,Rapamycin(RPM),an autophagy inducer,Tlr2-/-mice were randomly divided into PGPS group,PGPS+RPM 0.35?M low dose protection group,and PGPS+RPM 0.7?M high dose protection group.The audiological changes in mice with otitis media were evaluated by ABR test and tympanometer.Morphological experiments were performed to detect the in situ expression of autophagy factor p62 in pathological sections of middle ear tissues.TUNEL staining was used to observe the relationship between apoptosis and autophagy.Western blot was used to detect the expression of autophagy related factors and inflammatory factors in otitis media mice.Results:The results showed that Tlr2-/-mice were more sensitive to the induction of PGPS,invasion of the middle ear cavity appear more serious phenomenon,loss of hearing threshold,and detect the quantity of otitis media related inflammatory factor expression in mouse models,autophagy start signal protein LC3,autophagy substrate p62 protein levels also increased and the middle ear cavity epidermal cells appeared apoptosis,suggesting that autophagy degradation function damage,autophagy substrate exist a large number of accumulation,we assume that autophagy function of middle ear epithelium damage likely to be involved in the mechanism which causes otitis media.Later,rapamycin was used to verify that RPM could treat otitis media by repairing the function of autophagy degradation.The results showed that the treatment with rapamycin significantly reduced the occurrence of inflammation,reduced the amount of pus in the middle ear cavity,improved the morphology,decreased the expression of inflammatory factor TNF-?,decreased the expression of p62 factor protein,and reduced the degree of epidermal apoptosis in the middle ear cavity.RPM can repair the function of autophagy degradation and alleviate apoptosis,which can improve otitis media.Conclusion:The autophagy degradation injury of middle ear epithelial cells is involved in the mechanism of Tlr2-/-mice otitis media.We believe that rapamycin can induce or repair the autophagy degradation function of middle ear epithelial cells,thereby blocking inflammation and reducing apoptosis,and ultimately can treat otitis media and improve the ear function of mice.Repairing the function of autophagy degradation is a new way to treat otitis media,which opens up a new target for clinical treatment of otitis media.