ABSTRACT
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ABSTRACT
BACKGROUND AND OBJECTIVES: Detailed information on how an epithelial differentiation and elastic structures occurred in the developing eustachian tube would be helpful in understanding both normal physiology and pathology of the tubotympanum. This study was undertaken to establish elastic structures such as cartilage, elastic fiber, and collagen fiber in the embryonic mouse eustachian tube at a stage when epithelial differentiation is taking place. MATERIALS AND METHOD: Thirty four mice (BALB/c mouse), aged from gestational day 11 to postnatal day 21, were investigated using Verhoeff stain, Masson trichrome stain and alpha-1 antitrypsin immunohistochemistry. RESULTS: The cartilage-like structures were first found after birth, however, matured cartilages appeared at postnatal day 7. The elastic fibers and collagen fibers surrounding cartilage were abundantly found about 5 days after birth. alpha-1 antitrypsin, which is an strong inhibitor of elastase, began to be immunolabelled at gestational day 16. Its expression has been significantly increased after birth. CONCLUSION: Although the epithelial differentiation and maturation in eustachian tube occured at late embryonal stage, the elastic structures have developed and matured after birth. These findings might be a explanation to why young children are highly susceptible to otitis media.
Subject(s)
Animals , Child , Humans , Mice , Cartilage , Collagen , Elastic Cartilage , Elastic Tissue , Elasticity , Eustachian Tube , Immunohistochemistry , Otitis Media , Pancreatic Elastase , Parturition , Pathology , PhysiologyABSTRACT
BACKGROUND AND OBJECTIVES: The hyperproliferative character of human cholesteatoma epithelium was confirmed through various hyperproliferation associated antibody expressions. Among the various approaches for evaluating proliferative activity, thrombomodulin (TM) is a cell surface glycoprotein which forms a high affinity non-covalent complex with thrombin and is a differentiation marker for spinous layer keratinocytes. Several animal models have been introduced to study cholesteatoma pathogenesis, among which canal ligation model using Mongolian gerbils is of much interest, because it can potentially provide information on cell differentiation and proliferation of cholesteatoma. In this study, we investigated the hyperproliferative characteristics of canal ligation cholesteatoma by comparing deep meatal skin and retroauricular skin. Another purpose of this study was to provide the morphological basis for further animal studies concerning cholesteatoma pathogenesis. MATERIALS AND METHOD: Using immunohistochemical technique with anti-monoclonal antibody, we investigated TM expression in the canal ligation cholesteatoma, deep meatal skin and retroauricular skin of Mongolian gerbil. RESULTS: Experimental cholesteatoma induced by canal ligation and deep meatal skin showed TM expression especially in the suprabasal layers. TM expression of experimental cholesteatoma is much more intense than that of deep meatal skin. CONCLUSION: Experimental cholesteatoma revealed an altered differentiation in suprabasal layer, suggesting that this animal model can be used for further study in the epithelial differentiation and proliferation of cholesteatoma.