engleski

Development of the rat epiglottis

The ability for differentiation of various undifferentiated embryonal cells and tissues has been extensively investigated for regenerative medicine purposes that are replacement of tissues or organs damaged by trauma or disease. Altough epiglottis was used for palpebral reconstruction in human medicine, there are almost no data about early development of this organ in the rat or its ability to differentiate in a transplant. Moreover the adult rat epiglottis has not yet been subjected to TEM analysis. Fischer rat epiglottises were microsurgically isolated under the dissecting microscope from 17-days-old Fischer rat embryos and fixed or transplanted under kidney capsules of adult rats where they spent 14 days. The DNA demethylating agent 5-azacitidine (5azaC) (5mg/kg) was injected intraperitoneally to the experimental group during first three days. Rat adult epiglottises were explanted from three months old rats and fixed. Classical histological and TEM analysis as well as immunohistochemical detection of the Proliferating Cell Nuclear Antigen (PCNA) and quantitative sterological analysis of its expression (numerical density Nv) were performed. PCNA was expressed in almost all cells of the 17-days-old epiglottis while in transplants its expression was restricted to undifferentiated cartilage and epithelial cells. Differentiation of the cartilage and epithelia in transplants proceeded well but did not reach the stage of differentiation in adult epiglottis because they lacked elastic fibers and stratified squamous epithelium, respectively. 5azaC increased PCNA expression (Nv) in transplants. By this investigation new data about the development of the rat epiglottis were obtained.

rat; epiglottis; differentiation; 5-azacytidine; in vivo transplantation; PCNA

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