EGF, TGF-¦Á, HRG Impact On The Growth And Differentiation Of The Middle Ear Mucosa In Chronic Otitis Media Expression

Objective/Study Background Otitis media is a major cause of hearing loss in pediatric and adult patients. This pathologic condition is characterized by mucosal hyperplasia which induce accumulation of the middle ear secretion, adhesive otitis, tympanosclerosis, scarring of the middle ear mucosa, granuloma and cholesteatoma information, fibrosis, bone resorption or deposition, and lead to permanent damage of the middle ear cavity. It was proposed that several growth factors, by interacting with their cognate receptors, contribute to the middle ear mucosal hyperplasia during otitis media. The purpose of this study was to discussion the role of EGF, TGF-α and HRG for the growth and differentiation of the middle ear epithelium.Methods 25 male Wistar rats were decapitated and their middle ear bullae were surgically extracted. The middle ear mucosae were surgically removed intact from the anterolateral bullae and divided into roughly square tissue explants ranging from 0.5 to 1.0 mm~2. The explants were individually cultured with EGF, TGF-α or HRG at concentrations of 10, 100 and 1000ng per milliliter respectively. On day 12, the culture media were extracted and the explants fixed with 100% methanol. The fixed tissue was reacted withAE1/AE3 monoclonal mouse anti-human cytokeratin antibody, the diameter of the primary culture outgrowth and the average optical density of a portion of each well beyond the limits of cellular growth were measured with the Fluor chemTm9900 analytic software, and compared with the results of the control group. The data were analyzed with One-way ANOVA.Results EGF caused a significant increase in explant growth at concentrations of lOng. However, this effect was lost at lOOOng, which appeared to reduce explant growth below that of the controls. Although EGF at lOOng could increase explant growth, but this difference was not significant. TGF-a at concentrate 100, lOOOng and HRG at all three concentrates caused significant inhibition of tissue outgrowth. Although TGF-a at lOng could reduce explant growth, but this difference was not significant. EGF at concentrate 100, lOOOng had no effect on cytokeratin expression, but at lOng reduced the cytokeratin expression. TGF-a at concentrate 100, lOOOng and HRG at 10, lOOng caused a significant increase in cytokeratin expression.Conclusions This study demonstrated that EGF, TGF-a and HRG have a significant effect on the growth and differentiation of normal middle ear mucosal epithelium. EGF stimulates the growth of the epithelial cells, but inhibition them to differentiate into muture cells. Although TGF-a and HRG repress the growth of the epithelial cells, but the cells interfered with TGF-a and HRG differentiate well, and represent characteristics of the mature cell. Moreover, these effects depend the growth factors concentration. These results suggest that EGF, TGF-a and HRG contribute the pathology of the otitis media, effect and interfere the growth and differentiation of the middle ear mucosal epithelium.