Lamellar Inclusions in the Cytoplasm of Cilia Ted Cells

TBik I.: Lamellar Inclusions in the Cytoplasm of Ciliated Cells. Acta vet. Bmo, 63, 1994: 95-97. Numerous osmiophilic inclusions, with matrix arranged into concentric lamellae, were found in a zone between the nucleus and the subciliary layer of mitochondria in the apical cytoplasm of ciliated cells of the tracheal epithelium in tlle wild cat (Felis silvestris) and the tortoise Testudo hermanni. Their presence could be related to the existence of the granular endoplasmic reticulum and the Golgi complex in the cells. Their development by local coiling and condensation of the cytoplasm or by metamorphosis of mitochondria is also discussed. Ciliated cell, lamellar inclusion, upper respiratory tract The ultrastructural morphology of the ciliated cell, as revealed by electron microscopy, was studied about 25 years ago by a number of authors (Rhodin and Dalhamn 1956; Nilson 1958; Dalhamn 1961; Stegner 1961; Fredricsson and Bjorkman 1962; Gompel 1962; Larsen 1962; Nakai and Nagae 1970 and others). Their descriptions have shown general characteristics common to ciliated cells found in most animal species. Specific differences in the morphology of ciliated cells were investigated in amphibians by T B i k (1978) and in reptiles by Tesik (1980,1982,1984) and TeSik and Ned ved (1976). • However, with two exceptions, there are no mentions of the presence of any electron-dense myelin structures in the cytoplasm of ciliated cells in the mucosal lining of the upper respiratory passages. P a vel k a et al. (1976) have reported the findings of large electron-dense granules with lamellarly arranged content in the ciliated cells of the domestic cat (Felis domestica) and Tesik (1982) observed similar granules in the same tissue of the tortoise Testudohermanni. Materials and Methods In our research on the comparative morphology of respiratory epithelium in the large air passages of vertebrates, 47 animal species were investigated (4 amphibian, 21 reptile, 7 avian and 15 mammalian species). Out of these, only the wild cat (Felis silvestris) and tortoise (Testudo hermanni) showed the presence of electron-dense granules with contents corresponding to myelin formations. Samples of trachea, three from each species, were taken from adult animals of both sexes. Tissue was collected from the approximate centre and near the bifurcation of the trachea. Mucosa was fixed together with the supporting cartilage of the tracheal ring, which facilitated oriented embedding and sectioning. The tissues were fixed I % Os04 in 0.1 M phosphate buffer, pH 7.4, for 3 hat 0 °C or with 2.5 % glutaraldehyde in the same buffer for 2 h with subsequent fixation in I % OsO 4 at 0 °C for I h. Embedding was performed with Durcupan ACM by the method of Tesik and Volfova (1978). Blocks were cut using glass knives. Ultrathin • sections were contrasted (Reynolds 1963) and examined with a Tesla BS 500 electron microscope.