Adverse Effects Of Radon And Its Progeny On Target Tissues In Rats

It has become increasingly clear that radon dominates the radiation exposure of the general population from nature course. By observing the adverse effects of radon and its progeny on lung(viz. direct target tissue) and blood(viz. indirect target tissue), we try to investigate the biological effects of lung and blood in rats inhaled different concentration of radon and its progeny, and to explore the correlation between the pathological changes of PBMC (peripheral blood mononuclear cells) and BALF (bronchi alveolar lavage fluids), in the hope of providing experimental basis in selection of biological markers for radon and its progeny.20 male Sprague-Dawley rats were exposed to radon and its progeny at cumulative doses up to 66, 111 and 174 WLM (working month level), respectively. The total number and proportion of cells in BALF and in the peripheral blood were investigated. The proportion of lymphocyte was significantly lower and the proportion of granulocyte was higher than the control group(p<0.05). In the peripheral blood, the proportion of various cells did not show significant changes correspondingly, with an exception of a decrease in the proportion of lymphocytes in 66WLM group.The LDH activity in BALF suspension of the 111 WLM group was significantly increased. Compared with the control, the LDH activity of the exposed groups in the serum did not change significantly. The total protein level of the 174WLM group increased in BALF, but decreased inserum, showing a negative correlation between the total protein in BALF suspension and serum. On the other hands, the GSH levels in BALF suspension and serum changed only slightly.RT-PCR was applied to determine the expression of the IL-6 mRNA in both BALF and PBMC. A high IL-6 mRNA expression level was observed in the 174WLM BALF cells, but the expression of PBMC significantly increased in the 66 and 174WLM group.The pathological changes in the bronchia and lung of the 111WLM and the 174 WLM groups were characterized by the chronic inflammation. Permeation of the inflammatory cells to the myofiber layer in partial area, desquamation of the mucosa epidermis, hyperplasia of the connective tissue and formation of the focal emphysema were observed in relation with the exposure levels.SCGE (Single cell gel electrophoresis) was used to detect the DNA breakage in the BALF, lung cells and PBMC. The distance of DNA migration was positively dose-dependent, and a strong correlation of DNA migration between the PBMC and BALF was disclosed.The experimental results suggested that the DNA migrate in PBMC and the total protein level in serum could be useful and early indexes in prediction of the radon adverse effects on the target organs in future studies.