Regulation of the Oxidative Processes in the Organs of Mice under the Effects of Chemical and Physical Factors at Low Doses

Biophysics - The effects of the separate and combined action of lead nitrate in a wide range of doses, uranyl nitrate, and chronic low-dose gamma irradiation on the formation of oxidative stress in...     

Phospholipids composition in tissues of the root voles Microtus oeconomus inhabiting territories with elevated radioactive background

Phospholipid composition was studied in tissues of root voles Microtus oeconomus Pall. from natural populations inhabiting territories with increased levels of natural radioactivity. Lipid component of biological membranes of animal tissues was shown to have high sensitivity to action of chronic low-intensity irradiation at small doses. Under effect of various damaging factors on the organism, similar changes of membrane state indexes were noted, these changes being due to functioning of the physical-chemical system of cell metabolism regulation by oxidative reactions in membrane lipids. An important role of intrapopulational processes contributing essentially to formation of biological consequences of the low-intensity irradiation of animals in natural habitat was revealed.     

Dependence of response reaction of root voles to low-intensity irradiation on initial state of the tissue antioxidant system

There has been studied the response of antioxidant (AO) reaction of the tissue system of the root voles Microtus oeconomus Pall., whose parents belonged to the populations long inhabiting the Republic Komi regions with different degrees of radioactive contamination, on an additional irradiation at low doses. Differences have been revealed in the phospholipid content, activity of AO defense, intensity of processes of lipid peroxidation (LPO) in tissues of the offspring of voles caught in the control and contaminated regions. It has been revealed that direction and degree of changes in the offspring tissues after the additional action are determined by the parameter value in the non-irradiated animal group. Intensity of the LPO processes in liver and brain was leveled after the long low-intensity irradiation. The obtained data and analysis of literature indicate that at predicting effects of chronic action of low doses of a damaging factor both in experiment and in the natural habitation, it is necessary to take into account initial characteristics of biological objects.     

Effects of Populational Factors on Phospholipid Composition of Various Tissues in Natural Populations of the Tundra Vole Microtus oeconomus

The lipid composition of tissue membranes was studied in tundra voles at different phases of population cycle. At the period of depression of the volume of population, there were found a sharp rise of the content of lysophosphatidylcholine (LPC) in lipids of liver and spleen, the appearance of trace amounts of lysoforms in the brain tissue, and a reduction of portion of main fractions, particularly phosphatidylethanolamine (PE), in all studied tissues. It is at this period that the minimal content of more easily oxidizable fractions in phospholipids (PL) of all tissues was observed, with the maximal PC/PE ratio in lipids of liver and brain in most animal groups studied, which indicates the greatest rigidity of tissue membranes and minimal ability of lipids to oxidation. These particularities of the lipid fractional composition in vole tissues at different phases of population cycle are closely associated with the physiological state of the animals, specifically with their hormonal status depending on the population cycle phase, while elevation in the blood of stress-realizing hormones provides prerequisites for hyperactivation of peroxide oxidation of lipids (POL). The revealed pronounced changes of the tissue phospholipid composition in voles from natural populations at the depression of the population size can be considered as a part of non-specific reaction and associated intensification of POL processes.