Scientific journal
European Journal of Natural History
ISSN 2073-4972

INFLUENCE OF COMBINED EFFECT OF ASBESTOS DUST AND RADIATION IN DOSAGE OF 0,2 GY ON ENERGY METABOLISM IN LONG-TERM PERIOD

Ilderbayev O.Z., Zhetpisbayev B.A., Kozubayeva D.B., Yermenbay O.T.

The study of remote effects of radiation damage influence is one of important lines of radiation medicine as it touches such socially meaningful problems like longevity, reproductive function, genetic effects of radiation on posterity, blastomogenic and non-blastomogenic effects, etc. The living body´s bio-energetic disorder is of great importance in the pathology of X-ray sickness. It has been established that during the exposure the electron transport process in the cytochrome system, in chondriosomes of cells is broken and the process of oxidative phosphorylation disunites. The metabolic process regulation failure in cells can be not only the result, but also the most important component of pathogenetic mechanisms of radiation damage. The purpose of the present research has been the experimental study of cytochrome oxydase (CCO) and succinate dehydrogenase (SDG) energy metabolism enzymes´ activity in tissues of adrenal bodies and immunocompetent organs and cells in the long-term period after a combined effect of radiation and chrysotile-asbestos dust.

For the realization of the purpose 3 sets of experiments on 40 nondescript white rat males weighing 180±20 g were carried out. I group - intact (n = 10), II group - poisoned with chrysotile-asbestos dust (n = 15) and III group - poisoned + X-rayed (n = 15). For the simulation of experimental asbestosis the chrysotile-asbestos dust was administered to the trial rats´ lungs (intratracheally) by the method of Gorodetskaya Ye.N. in the modification of Parashina V.I.. The III group animals were exposed to the radiation of 0,2 Gy one time 90 days before the investigation on the radiotherapy unit Agat-PM60Сo. The animals were killed by an incomplete decapitation method in two months after the intratracheal administration. The animals were killed according to the International recommendations on carrying out medico-biological research using animals (WHO Chronicle, 1985). For the investigation lymphocytes were segregated from the peripheral blood and homogenates were prepared from the liver, milt, and thymus, lymph glands of the small intestine and adrenal bodies. The research findings were analyzed by standard methods of variation statistics using Student´s test criteria.

As the investigations showed, when affected with chrysotile-asbestos dust, the CCO and SDG enzymes´ activity in the adrenal body decreased 1,6 times and 3 times (р<0,001) accordingly. In the III group animals subjected to the combined effect a sharp decrease of the SDG activity up to 0,014±0,002 (р<0,001) was registered, and the CCO activity didn´t differ authentically from the control parameter. In its turn, these enzymes´ activity decrease was also registered in the peripheral blood lymphocytes: in the II group the SDG activity decreases twice (р<0,001), and the CCO one - 1,4 times (р<0,05). Proceeding from the findings one can resume that in the abovementioned cells the energy metabolism enzymes´ activity decrease in the long-term period takes place, when subjected to the combined dust-radiation factor.

In the thymus at the asbestos dust affect the SDG activity increase 1,8 times (р<0,01) was registered, and the CCO activity decreased up to 0,117±0,011 (р<0,01). In the II group animals the CCO activity was fixed at the level of 0,259±0,027, and in the control animals this factor was within the limits of 0,198±0,012 (р<0,05). From the side of SDG a tendency to increase compared to the control was depicted in the thymus. As the investigations showed, in the II group animals an authentic SDG activity increase was registered in the liver and lymphatic glands: 17 times and 8,5 times (р<0,001). In this case after asbestic poisoning the SDG activity increase was attended by the CCO activity decrease 1, 8 times (р<0,05) and 1,4 times (р<0,01) accordingly. There were no significant changes in the liver and lymph glands of the small intestine registered in the animals after the dust-radiation factor from the side of the CCO activity, its content almost conformed to the control values. The SDG enzyme´s activity increase 4 times in the small intestine lymph glands and 10 times in the liver (р<0,001) was placed on record. The milt CCO activity in the animals after the dust pollution and combined effect didn´t change authentically (р>0,05), and from the side of the SDG activity the 1,9 times decrease compared to the control value (р<0,05) in the II group, 2,1 times - in the III group (р<0,05) was registered.

The found out many-valued enzyme activity changes substantiate the supposition about a varied level of metabolic cost associated with specific and non-specific responses of the body at the combined effect of the factors. The high energy metabolism activity degree seems probable to be associated with the concentration of catecholamines, glucocorticoids and the dehydrogenase change rate in the Krebs cycle at the radiation injury of the body as one of the compensatory responses of the body to noci-influences. It was found out in the experiment that in the long-term period after the combined effect the SDG activity increase in the liver and lymph glands and its decrease in the milt, adrenal bodies and lymphocytes take place. The low CCO activity in the long-term period is registered in the peripheral blood lymphocytes.

The work is submitted to III International Scientific Conference "Basic Research", Dominican Republic, April, 10-20, 2008, came to the editorial office on 19.03.2008.