鼓索・舌神経切除によるウサギ茸状乳頭の形態的変化に関する電子顕微鏡的研究

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The epithelia of rabbit fungiform papillae and filiform papillae were studied by electron microscopy. Further, filiform changes observed in the dorsal epithelium of fungiform papillae after chorda-lingual neurectomy were studied by scanning electron microscopy ; the state of keratinization of the epithelium was observed by transmission electron microscopy ; and the findings were compared with those in the epithelium of normal filiform papillae. The surface of fungiform papillae was relatively smooth, and the dorsal epithelium was covered by a thin keratin layer with no keratohyalin granules. In filiform papillae, the nature of keratinization was quite different between the epithelial cell layers on the anterior and posterior aspects of the papillae. On the anterior aspect, epithelial cells contained many keratohyalin granules, were nucleated to the topmost layer, and formed a soft keratin layer, showing a strong tendency toward parakeratosis. On the posterior aspect, in contrast, the cytoplasm of epithelial cells was rich in ribosomes and tonofibrils, but few keratohyalin granules were noted. The superficial cells had no nuclei or cell organelles and showed true keratinization, forming a hard keratin layer. After chorda-lingual neurectomy, taste buds in fungiform papillae degenerated, and marked progression of keratinization was observed in the dorsal epithelium of many fungiform papillae 1 week after denervation. The keratin layer on the dorsal aspect of these papillae was thickened, and the papillae were characteristically pointed as in filiform papillae and curved toward the pharynx. These changes became more notable with time, and the fungiform papillae were difficult to distinguish from surrounding filiform papillae by scanning electron microscopy 6 months after denervation. In the dorsal epithelium of fungiform papillae showing marked changes, transmission electron microscopy showed a pseudokeratotic layer occasionally containing condensed nuclei in the anterior aspect of the papillae but a keratin layer without nuclei or cell organelles in the posterior aspect. The ultrastructural examination of markedly degenerated fungiform papillae revealed a dual keratinization pattern similar to that in the epithelium of filiform papillae. Keratohyalin granules were observed in fungiform papillae showing marked keratinization. The appearance of keratohyalin granules not observed in normal fungiform papillae showing only mild keratinization suggests that they play a role in keratinization of fungiform papillary epithelium.
九州歯科学会の論文
1994-02-25

鼓索・舌神経切除によるウサギ茸状乳頭の形態的変化に関する電子顕微鏡的研究

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