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KMID : 0368019830060040371
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Journal of Soonchunhyang University
1983 Volume.6 No. 4 p.371 ~ p.377
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Morphological Study on the Skin of the Aging Frog(Xenopus laevis)
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Abstract
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Age differences in the skin structure have been studied in young (one year-old) and aged (five and a half years-old) frog, Xenopius laevis. Pieces of the skin were taken from the central area of the back and abdomen, fixed in Karnovsky´s fixative (phosphate buffer, pH 7.3) and post-fixed in 1% osmium tetroxide (phosphate buffer, pH 7. 3). The sections 1 pm in thickness were made on a LKB-IQ ultramicrotome, and were stained with toluidine blue.
In order to assess the general level of metabolic activities in epidermal cells, pieces of the skin from the frogs of the two age groups were incubated in amphibian physiological saline containing 50 pCi/ml of 5-3H-uridine with a specific activity of 25.9 Ci/m mole (New England Nuclear). The labeling was carried out for 30 minutes at 20´±1´C. Sections 1 pm in thickness were cut on a LKB- ultramicrotome and mounted on glass slides. The mounted slides were -coated with Kodak NTB 3 nuclear track emulsion in routine manner, exposed for a period of 1 or 2 weeks, and developedwith Kodak D-19. The tissues were studied with light microscope. Observed results were as follow;
1. The epidermis in young frogs is-made up of an average of 6.3 and 4. 7 layers of epithelial cells at abdominal and back skin, respectively.
2. In aged frog, the number of epithelial cell layers at abdominal and dorsal surfaces Increases to 8.8 and 5. 6.
3. The thickness of the dermis(spongiosum) in aged frogs is decreased 25% on the abdominal side (from 267pm to 207pm), but is increased by 11% on the dorsal side (from 275 pm to 305pm).
4. The nucleolar index and radioactive index, by epithelial cells are drastically reduced in aged frogs.
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