Electron Microscopic Radioautographic Studies on Macromolecular Synthesis in Mitochondria of Animal Cells in Aging.
doi: http://dx.doi.org/10.5016/1806-8774.2010v12p1
Abstract
In order to study the aging changes of intramitochondrial DNA, RNA, protein synthesis of mouse organs during the development and aging, 30 groups of developing and aging mice, each consisting of 3 individuals, total 90, from fetal day 19 to postnatal newborn at day 1, 3, 9, 14 and adult at month 1, 2, 6, 12 to 24, were injected with one of the 3H-labeled precursors, 3H-thymidine, 3H-uriidine, or 3H-leucine, sacrificed 1 hr later and the liver tissues as well as the adrenal, lung and testis tissues were taken out, fixed and processed for electron microscopic radioautography. On electron microscopic radioautograms obtained from each animal, numbers of mitochondria per cell profile area, numbers of labeled mitochondria and the mitochondrial labeling index labeled with 3H-labeled precursos showing DNA, RNA, protein synthesis in each hepatocytes, adrenal cortical and medullary cells, pulmonary cells, testis cells were counted and the results in respective developing and aging groups were compared, respectively.
From the results, it was demonstrated that the numbers of mitochondria in hepatocytes as well as in 3 zones of the adrenal cortex, the zona glomerulosa, fasciculata and reticularis, adrenal medullary cells, pulmonary cells, testis cells of mice at various ages increased from fetal day 19 to postnatal month 1 and 2 due to development and aging of animals. On the other hand, the numbers of labeled mitochondria and the labeling indices of intramitochondrial DNA, RNA, protein syntheses incorporating 3H-thymidine, 3H-uriidine, 3H-leucine in hepatocytes, 3 zones of adrenal cortical cells, medullary cells, pulmonary cells and testis cells increased from fetal day 19 to postnatal month 1 and decreased to month 24. From the results, it was shown that the activity of intramitochnodrial DNA, RNA, protein syntheses in hepatocytes, adrenal cortical and medullary cells, pulmonary cells and testis cells in developing and aging mice increased and decreased due to development and aging. The intramitochondrial DNA, RNA and protein syntheses in some other organs were also reviewed and discussed.
From the results, it was demonstrated that the numbers of mitochondria in hepatocytes as well as in 3 zones of the adrenal cortex, the zona glomerulosa, fasciculata and reticularis, adrenal medullary cells, pulmonary cells, testis cells of mice at various ages increased from fetal day 19 to postnatal month 1 and 2 due to development and aging of animals. On the other hand, the numbers of labeled mitochondria and the labeling indices of intramitochondrial DNA, RNA, protein syntheses incorporating 3H-thymidine, 3H-uriidine, 3H-leucine in hepatocytes, 3 zones of adrenal cortical cells, medullary cells, pulmonary cells and testis cells increased from fetal day 19 to postnatal month 1 and decreased to month 24. From the results, it was shown that the activity of intramitochnodrial DNA, RNA, protein syntheses in hepatocytes, adrenal cortical and medullary cells, pulmonary cells and testis cells in developing and aging mice increased and decreased due to development and aging. The intramitochondrial DNA, RNA and protein syntheses in some other organs were also reviewed and discussed.
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PDFDOI: https://doi.org/10.5016/1806-8774.2010v12p1