Dioxide Plutonium-239 in the Lung. Report 3: Different Effect of Vitamins A, C and β-carotene on the Long-term Consequences of Incorporation

Purpose: Testing of vitamin preparations as a means of prophylaxis long-term effects of destruction of incorporated radionuclides. Analysis of experimental material about the influence of L-ascorbic acid, retinol palmitate and β-carotene on the long-term effects inside the lungs of incorporation dioxide plutonium-239. Material and methods: The studies were performed on 628 white nonlinear male rats. Plutonium dioxide was administered to white nonlinear male rats once intratracheally in the amount of 100 kBq/kg body weight. The diet was enriched by L-ascorbic acid, retinol palmitate or synthetic β-carotene. The analysis of pathological effects inside the lungs of incorporation of the plutonium dioxide was carried out by groups formed based on individual absorbed doses in the range of their geometric means between 32 and 212 Gy. Test animals were observed for life. Radiometric, histological and statistical methods were used. Indicators of the pathology of the organ of respiration were inflammatory, sclerotic, premalignant and malignant changes in the lungs. Indicators of breathing pathology: inflammatory, sclerotic, premalignant and malignant changes in the lungs are quantified. Results: Long-term consumption of vitamins C, A and β-carotene in intact rats did not affect the life span of animals and the total frequency of the identified types of lung cancer. We found a significant increase in the frequency of pneumosclerosis in groups of rats received vitamin A (27 %) or β-carotene (29 %) compared with intact animals (11 %). Multidirectional effect of vitamins A, C and β-carotene on selected indicators of long-term effects inside the lungs of incorporation 239PuO2 has been marked. Vitamin A and β-carotene intensified the sclerotic processes in the organ of respiration, and vitamin A largely (67 %) than β-carotene (57 %) with 46 % in controls. When enriching the ration of animals with the studied vitamin preparations, the regularity of increasing the number of rats with tumors localized in the lungs was preserved. Both positive and negative influence on radiation carcinogenesis and the lack of effect depending on the absorbed dose was noted. With the increase of absorbed dose from 32 to 212 Gy not only the frequency but also the spectrum of tumors localized in the lungs has varied. Against the background of increasing the total number of tumors has increased the number of rats with tumors of epithelial origin and decreased with gematosarcoma. No effect is investigated vitamin preparations on the metabolism of plutonium dioxide-239 installed. Consumption of the studied drugs did not affect the lifespan of rats with intra-lungs the introduction of dioxide of plutonium-239 and the process of formation of absorbed doses in the lungs. Conclusions: Vitamin A and β-carotene stimulate the development of pulmonary fibrosis in rats of intact and affected 239PuO2 ones. The result of the use of vitamins A, C and β-carotene showed the different (positive and negative) effect on the formation of lung tumors induced 239PuO2 in various ranges of absorbed doses. In the studied forms, doses and schemes assign vitamins A, C and β-carotene cannot be recommended for the prevention of spontaneous and 239PuO2-induced pathological changes in the lung.