EUROMEDICA  Hanover 6-7  Juni 2008	Advanced methods of diagnosis, treatment and prophylactics
	European Academy of Natural Sciences, Hanover European Scientific Society, Hanover Russian Academy of Natural Sciences, Moscow

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Objective of this research was studying the condition of lipid peroxygenation (LP) in animals exposed to various concentrations of uranium ore dust (DUO).

The materials and research methods

Experiments were conducted in 120 nonlinear rats. Inhalational influence by uranium ore dust was carried out in vitro, in special exposure chambers UIZ-1. Experimental animals were divided into two testing groups. In the first group the animals were exposed to chronic inhalational of DUO in a dose of 5 maximum concentration limits (MCL) (10,7 mg/m3 U); in the second - in a dose of 10 MCL (20,5 mg/m3 U). Controlling for each testing group were the animals which were kept in identical exposure chambers, but were not exposed to DUO. DUO inhalation was carried out during 5 days a week, for 4 hours per day continuously throughout 120 days. The condition of the LP was estimated according to concentration of malondialdehyde (MDA) and superoxide dismutase (SOD) in lungs after 1, 2, 3, and 4 months from the beginning of the research.

Research results

Results of the conducted series of research showed that at DUO influence on animals in a dose of 5 MCL, the level of MDA formation after 1 month from the influence beginning increased in comparison with the control group by 83.2 %. During the next 2 months signs of MDA accumulation in lungs remain, but its accumulation was lower than on the 30th day of the observation. A sharp excess above normal values was discovered upon the exposure by the end of 4th month – on 242.6 %. Hence, dosage dependence exerts upon a long, over 3 months, influence at daily inhalation of DUO in a dose of 5 MCL.

At influence of DUO by a dose equal to 10 MCL the similar picture of changes of MDA concentration indicators revealed in all terms of the observation. Similar to the previous series of the observation, the steady effect of increase in MDA formation occurs after 4 months from the beginning of influences and specifies that the time threshold of priming in 3 and 4 months of influences is critical.

The main mechanism of protection of an organism from free radicals is enzyme of SOD. Finding the SOD activity in lungs at influence of DUO in doses of 5 and 10 MCL showed that essential changes of activity of antioxidant SOD enzyme were marked in the rats’ lung tissue. At that the expressiveness of this indicator depended on duration of influence of DUO. At the tested animals decrease in activity of enzyme in all terms of experiment was observed, but the most considerable it was by the end 4 months of observation on 83.2 % at influence of DUO by a dose of 5 MCL and on 71.3 % at a dose of 10 MCL.

Thus, the conducted researches testify that influence by the dust of uranium ore leads to an exhaustion of antioxidant systems, especially aggravated upon duration of the exposure.