Age-related changes of RNA synthesis in the lungs of aging mice by light and electron microscopic radioautography.
The changes of RNA synthesis and morphology in the lungs of aging mice from fetal day 16 to 22 months after birth were investigated by means of light and electron microscopic radioautography after 3H-uridine incorporation. Eleven groups of mice, each consisting of 3 animals from embryo day 16 to newborn, weanling, adult and senescent were used. Lung tissues were labelled in vitro with 3H-uridine and fixed, embedded, sectioned and radioautographed. The localization and number of silver grains were analyzed. The radioautograms revealed that all types of pulmonary tissue cells were labelled. The number of silver grains in respective cell types indicating the RNA synthesis changed with aging. The activity of RNA synthesis of type 1 epithelial cells increased gradually from the first day after birth, reached a peak at 1 week after birth, then decreased with aging. The RNA synthesis of type 2 epithelial, interstitial and endothelial cells increased gradually from fetal day 16, reached the peaks at 1 week after birth, then diminished with the developing of the lung due to aging.
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Department of Anatomy and Cell Biology, Shinshu University, School of Medicine, Matsumoto, Japan.
D000375:Aging / Q000378:metabolism*; D000818:Animals; D001345:Autoradiography; D004727:Endothelium / Q000166:cytology / Q000378:metabolism; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D005260:Female; D005333:Fetus / Q000166:cytology / Q000378:metabolism; D008168:Lung / Q000166:cytology / Q000378:metabolism*; D008297:Male; D051379:Mice; D008854:Microscopy, Electron; D012313:RNA / Q000096:biosynthesis*; D014316:Tritium; D014529:Uridine / Q000378:metabolism
D014316:Tritium; D012313:RNA; D014529:Uridine