The Effects Of Radon And Its Daughter On Targeted Organs And Protective Effect Of Radon-protection Agent In Rats

Objective:To study the effects of radon and its daughter on lung tissue, peripheral blood cellsand serum tumor markers of rats and to discuss its mechanism, furthermore to screenearly molecular biomarkers of radon exposure and to observe the effect of protectiveagent which is extracted from traditional Chinese herbs.Methods:1) Rat model of radon-esposure:30male SD rats were randomly divided into fivegroups with six rats in each group: control group,60working level month (WLM)group,90WLM group,120WLM group and radon protective group (rats were givenradon protective agent in the group). All groups except the control one were placed inmultifunctional ecological radon chamber. The protective group was given protectiveagent of3ml per rat before radon exposure in radon chamber. The control group wasplaced in an animal room with a background concentration of radon less than80Bq/m3.The other condition was the same with radon exposure rats.2) Pathological changes of lung tissue: After finished radon exposure, all rats wereanesthetized and its lung and bronchial were removed and were fixed with neutralformalin liquid. The tissue were general dipped and sliced by HE stained and observedunder microscope.3) The concentration of superoxide dismutase (SOD) activity and malondialdehyde(MDA) were detected respectively by xanthine oxidase-hydroxylamine method andthiobarbituric acid method of lung tissue.4) The numbers and proportions of white cells in peripheral blood were counted byfive-classification hematology analyzer.5) The levels of CEA、NSE、CYFRA21-1and p53antibody in serum of rats were determined by enzyme linked immunosorbent assay (ELISA).6) SAS V8system was used for statistical analysis.The data was shown as mean±standard deviation（x±s）. A P-value of less0.05was considered statisticallysignificant.Results:1) Pathological changes in lung tissue: In radon exposure groups, a series ofpathological alterations were observed including hyperemia and edema in the alveoli,emphysema, infiltration of acute or chronic inflammatory cells, alveolar septumfracture、fusion and bulla formation. These pathological changes were sharpenedfollowing the increasing of cumulative exposure doses of radon. Comparing to the120WLM group, the pathological injury in the lung was significantly reduced in radonprotection group. Cellular atypical changes and precancerous lesions cells were notfound in all groups.2) Oxidative damage:The concentration of MDA in lung tissue was significantlyincreased (P<0.05) and the activity of SOD was significantly decreased (P<0.05)following the increasing of radon cumulative exposure doses. But the activity of SODwas increased (P<0.05) and concentration of MDA was decreased in radon protectiongroup (P<0.05) compare to the120WLM group.3) Compared with control group, white blood cells counts were no remarkabledifference (P>0.05),but the proportions of the granulocytes was significantly increased(P<0.05) and the lymphocytes was remarkably decreased (P<0.05) in radon exposuregroups. In radon protection group, the counts of both white blood cells and thegranulocytes were decreased obviously (P<0.05) but the lymphocytes count was nochanges (P>0.05) significantly compare to the120WLM group.4) The levels of tumor markers and p53antibody were investigated in all groups.Compared to control group, the serum levels of CEA、NSE、CYFRA21-1and p53antibody significantly increased in radon exposure groups following increasing of radoncumulative exposure doses (P<0.05). But the levels of CEA、NSE、CYFRA21-1andp53antibody were obviously decreased (P<0.05) in radon protection group comparedto120WLM group (P<0.05). Conclusions:1) Pathological changes of lung tissue in radon exposure rats include: interstitiallung congestion, edema, inflammatory cells infiltration, alveolar septum fracture, bullaformation etc. Those pathological changes are sharpened following the increasing ofradon cumulative exposure doses. These pathological changes are probably associatedwith the increasing of MDA level and the decreasing of SOD activity in the lung tissue.2) The increasing proportion of granulocytes and decreasing proportions oflymphocytes are related with the accumulation exposure doses. It reveals thatgranulocytes/lymphocytes ratio can be used possibly as a reference indicator for thejudgment of radon cumulative exposure doses.3）The serum levels of CEA、NSE、CYFRA21-1and p53antibody are associatedwith radon exposure dose. Maybe they can be used as early indicators for healthyexamination and early-stage lung cancer screening of people who exposed to high radonenviroment.4）Radon protection agent exhibite idea protective effect for radon exposureinjury. It can significantly decrease lung tissue injury and the level of serum tumormarkers.It is to worthy of to be studied furthermore.