[Influence of ionizing radiation on enzymatic activity and state of nucleus-nucleolar apparatus in rat hepatocytes].

L S Nersesova, M G Gazariants, Z S Mkrtchian, G O Meliksetian, L G Pogosian, S A Pogosian, L L Pogosian, E M Karalova, A S Avetisian, l O Abroian, Z A Karalian, Zh I Akopian

Index: Radiats. Biol. Radioecol. 53(1) , 55-62, (2013)

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Abstract

The effects of a single exposure of rats to the whole-body roentgen irradiation at the doses of 3.5 Gy and 4.5 Gy on the activity of creatine kinase, purine nucleoside phosphorylase, alanine aminotransferase, aspartate aminotransferase, as well as on the state of the nuclear-nucleolar apparatus in rat hepatocytes on the 6th and 13th days after radiation exposure have been studied. Irradiation at the above doses induced changes in the levels of enzymatic activity of different values and different directions within the same time periods, as well as oscillating changes in this type of enzymatic activity over time. This demonstrates various radiosensitivity and adaptation abilities of these enzymatic activities. The changes in the enzymatic activity significantly correspond to the changes in the morphometric indices of nuclear-nucleolar apparatus of hepatocytes, as well as the distribution of hepatocytes within the ploidy classes: in particular, stabilization of the enzymatic activity on the 13th day after irradiation correlates with the increased transcriptional activity, which is detectable through the increased number of nucleoli per nucleus and the expanded space of a hepatocyte nucleus. The compensation mechanisms are likely to be targeted at the changes in the functional activity of surviving hepatocytes, rather than at the replacement of the damaged cells by the new ones.