The objective of this research is to assess the effect of combined exposure of a high dose gamma radiation (6Gy) and coal dust on the immune system values in the long-term period. The study was carried out on 40 male Wistar rats divided into 4 groups: group I, intact animals; group II, exposure to coal dust; group III, exposure to 6Gy -irradiation; group IV, combined exposure to sublethal irradiation and coal dust. In groups II and IV, anthracosis was caused by exposure to coal dust at a concentration of 50 mg/m3, using an exposure chamber for 90 days after irradiation. The animals of groups III and IV were irradiated once in dose 6Gy prior to the study, with the TERAGAM CO60 gamma-therapeutic device (ISOTREND spol. s.r.o., Czech Republic). The study revealed a significant immunotoxicological shift induced by coal dust and high dose of radiation separately and in combination. The combined effect of factors exhibited an obvious immunodeficiency, as compared to the separate exposure. The combined exposure to the studied factors resulted in deterioration of T-cell immunity and disruption of cytokine production accompanied by reduced resistance to neoplasms, increased tendency to allergic diseases, and weakened immunological response of the organism.

The purposes of this study were to research immune system changes and liver and lung tissues in irradiated rats after prolonged exposure to coal dust. A study was carried out on 30 male Wistar rats that were divided into 3 groups: group I, intact animals; group II, exposure to coal dust and 0.2 Gy γ-irradiation; and group III, combined exposure to 6 Gy γ-irradiation and coal dust. The combination of a low and sublethal dose of γ-irradiation with coal dust leads to a significant change in immunity at the remote period. Particularly, the increase in radioactivity at the combined effect causes weakening of phagocytosis, and reduction in T lymphocytes by a factor of 2, immunoglobulin imbalance, and cytokine dysfunction develop secondary immune failure. During prolonged inhalation with coal dust of irradiated animals with the dose of 0.2 Gy, fibrosis and perivascular sclerosis of the bronchial wall of the lungs are formed, and perivascular fibrosis is formed in the liver. The increase in exposure dose up to 6 Gy in combination with coal, in the distant period, caused pulmonary hypertension amid hypertrophy of light arterial vessels and fibrous changes in arteriole, and destructive changes and collection necrosis develop in liver parenchyma. In the case of dust radiation synergy, the increase in doses leads to a significant immune deficiency, which occurs according to the “dose effect” principle; increases damage to animal tissues; and leads to liver tissue necrosis, pulmonary fibrosis, and pulmonary hypertension.