STOREDB:STUDY1047 Lung Cancer in Rats Exposed to Radon/Radon Daughters [DOI:10.20348/STOREDB/1047]
|Lung Cancer in Rats Exposed to Radon/Radon Daughters|
|Published: Open access to everyone|
|BIOLOGICAL SAMPLE AVAILABLE|
|Purpose: To determine the risk of radon at low levels and to determine the effects of confounding factors which act in exposure to radon in mines vs. that in homes.
Status: 1992- ongoing, all exposures terminated, some data available, to be completed in 2002
Treatment: Radon exposure is carried out in a specially designed exposure chamber allowing continuous exposure (up to 3 months) under well defined conditions (recirculating air and removal of carbon dioxide, ammonia, humidity and replenishment of oxygen. The experiment consists of 3 parts:
1) the study 1 of the dose effect relationship between 200 and 3200 WLM at the same dose rate of 1000 WL. 2) the study of the effect of dose rate between 250 and 2000 WL at a constant dose of 1000 WLM and 3) the study of the effects of low dose/ low dose rates.
Dosimetry: Determination of radon/radon daughters (218Po, 214Bi, 214Pb) in inhaled air and their potential alpha energy concentration (PAEC), including unattached fractions, deposition in lung of the radon daughters. For low fp (<2%) energy deposited equivalent to 1.5 mGy/WLM
Endpoints: Life-span study with necropsy observation and histopathology of all macroscopically obvious abnormalities. Lungs cleared to determine the absolute number of lung lesions. In addition, to the life span study and the determination of deposition, early effects, nuclear aberrations in alveolar macrophages and cell proliferation of bronchial and alveolar epithelial cells, were investigated 14 days after cessation of exposure. To this end, bromodeoxyuridine was injected i.p 4 hours before sacrifice.
Animal: Male Sprague-Dawley rats age 12 weeks.
Results: An inter-comparison of the exposure facilities at the CEA (see 02.01 to 02.16) and TNO (see 11.04) showed reasonable agreement between exposure conditions. A preliminary study on cell proliferation in male rats of different age exposed to 440 WLM demonstrated that it is not appropriate to use animals younger than 12 weeks. Deposition checked by measuring Bi-214 and Pb-214 showed a good correlation with exposure. The incidence of abnormal (micronucleated, binucleated, fragmented nuclei) cells increased with exposure with micro- and bin-nucleated cells decreasing at higher doses. The studies on life span and p53 gene expression are still under way. From the interim results, it appeared that 1) high doses (1000 WLM) reduced survival at high dose rates (2000 WL), 2) low doses (100 WLM) reduced survival at high dose rates (790 WL)3) high dose rates (1000 WL)reduced survival at high doses (3200 WLM), 4) low doses (100 WLM) had no effect of the 'unattached' fraction on survival
STOREDB:DATASET1081 Link to data and details in ERA [DOI:10.20348/STOREDB/1047/1081]
Created on:2016-09-30 17:27:28 Modified On:2016-09-30 17:27:28
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