TRACE ELEMENTS IN MEDICINE (MOSCOW)
2015. 16(3): 38-44
ORIGINAL PAPERS

ELEMENT BALANCE AND ENERGY EXCHANGE IN BRAIN HEMISPHERES OF MICE AT RADIATION EXPOSURE

L.L. Klimenko, O.V. Protasova

N.N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, Kosygin str. 4, Moscow, 117334, Russia; E-mail: klimenkoll@mail.ru

DOI: 10.19112/2413-6174-2015-16-3-38-44 

ABSTRACT: Content of Cu, Fe, Mg, Mn, Mo, P, S, Zn was investigated by the method of atomic emission spectral analysis with inductively coupled argon plasma in cerebral hemispheres of mice in control and experimental groups. The experimental group was exposed to radiation with overall dose of 7 Gr. The radiation-induced imbalance of Cu, Zn, Mg, Mn, Mo, P, S, in the cerebral hemispheres testifies to participation of inorganic components of proteinaceous matrixes in formation of primary radiochemical reactions. The most significant effect of the radiation on cerebral energy metabolism and elemental balance was a decrease in concentration of phosphorus in brain tissue of the right hemisphere for 14% and lack of reliable quantitative changes of phosphorus in the left hemisphere. It was shown that violation of phosphorus metabolism is one of the most significant primary radiation damages of the central nervous system. Earlier we have shown that violation of phosphorus biochemistry in liver, kidneys, spleen of easy irradiated animals is a primary reaction of tissues to radiation defeat. Decrease in body phosphorus concentration was registered in all studied irradiated animals, the most considerable in a spleen. As phosphate represents universal energy "change" in living organisms, it is possible to consider an established fact that primary reaction to radiation exposure in whole bodies and tissue of the right brain hemisphere is characterized by violation of phosphatic transfer and its activation by ions of metals. Earlier it was established that violation of the mediated oxidizing phosphorylation in the irradiated organism can be determined by reduction in the rate of phosphate inclusion in body fractions, by a delay of inorganic phosphate in blood and its strengthened removal with urine. Also it was established that even at early stages of radiation sickness there is a sharp suppression of phosphate inclusion of in the DNA fractions in liver, kidneys, spleen and small intestine. A peculiar reaction of СNS to penetrating radiation is more expressed quantitative change of phosphorus concentration in brain tissue of the right hemisphere with no correspondent change in the left hemisphere. It is known that the energy ensuring transmembrane transfer of sodium and potassium necessary for passing of nervous impulses is very sensitive to concentration of high-energy compounds. At relative rest, energy expenses are 10-15% of all ATP formed in the brain per unit time. At the change of functional state, especially at excitement, the energy consumption increases and can reach 40% in cerebral cortex of mice. High energy consumption of the brain in comparison with other organs is confirmed by energy production assessment: if energy production of the brain (µmol P•min-1•g-1) for adult mice makes 26.8 µmol, for a liver it is twice less, and for kidneys – thrice less: intensity of energy metabolism is one of the key factors determining activity of the brain. Thus, a decrease in concentration of total phosphorus in the right hemisphere for 14% after radiation exposure is undoubtedly a critical quantity for cerebral energy metabolism and is associated with idea of its asymmetric post-radiation deficiency. Registration of DC-potential in the control group of animals showed that average values of DC-potential in cerebral hemispheres don't statistically differ within the group. After irradiation, in whole experimental group in the right cerebral hemisphere there was a decrease in DC-potential by 53%, while in the left hemisphere average value of DC-potential didn't change. The fact of post-radiation decrease in DC-potential, as a marker of a cerebral energy metabolism, in the right hemisphere, as well as a decrease in concentration of phosphorus in this hemisphere, testifies to different sensitivity of functionally inadequate hemispheres to radiation. The inversion of hemispheric domination observed in this experience is a mechanism of physiological adaptation: if in control the left hemisphere had lower DC-potential in comparison with the right one, after the irradiation DC-potential in the right hemisphere became reliable lower, than in the left. We observed the similar fact of bigger sensitivity of the right hemisphere to radiation earlier at research of accelerated radiation aging. Thus, when considering independent indicators of cerebral energy metabolism, the bigger sensitivity to radiation exposure was found in the right hemisphere. Possibly, in the right hemisphere, more connected with vegetative reactions, than the left one, under the influence of radiation there is more intensive weakening of cerebral blood flow, increase in permeability of the brain-blood barrier, decrease in consumption of oxygen, and dissociation of oxidizing phosphorylation – i.e. the complex of neurophysiological and neurochemical reactions leading to suppression of cerebral energy metabolism.

KEYWORDS: macro elements, trace elements, atomic emission spectral analysis, DC-potential, cerebral energy metabolism.