Lung cancer response following inhaled radon in the A/J and C57BL/6J mouse.
A/J and C57BL/6J mice, strains which differ in susceptibility to chemical-induced lung tumours, were examined for differential sensitivity to radon-induced lung cancer. Sixty weeks after exposure to 952 WLM radon (3.34 J h1 m-3), no lung tumours were found in the control, sham- (one dust-) exposed, or radon-exposed C57BL/6J mice. In contrast, each of the A/J groups had a substantial number of tumours. Although there were no differences in overall lung tumour incidence or multiplicity associated with radon and ore dust exposure in A/J mice, distinct differences in tumour size and histopathological appearance were noted. The ratio of lung adenoma-to-carcinoma found in control A/J mice was 10:1, whereas the ratio in one dust-exposed animals was 10:8 and that in radon-exposed animals was 8:6. Based on these data, particulates appear to modify the promotion-progression of lung cancer in this strain. In addition, the appearance of two very large carcinomas histologically resembling Clara-cell-derived tumours only in the radon-exposed A/J mice and the possibility of alpha-particle-induced killing of target cells in the radon-exposed animals suggests that A/J but not the C57BL/6J, mice may have genes that modify susceptibility to radon-induced lung cancer.
Groch
K M
KM
Molecular Biosciences Department, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
Khan
M A
MA
Brooks
A L
AL
Saffer
J D
JD
D000512:Alpha Particles; D000818:Animals; D004391:Dust; D008175:Lung Neoplasms / Q000235:genetics*; D008297:Male; D051379:Mice; D008805:Mice, Inbred A; D008810:Mice, Inbred C57BL; D015162:Micronucleus Tests; D009381:Neoplasms, Radiation-Induced / Q000209:etiology*; D011886:Radon; D013997:Time Factors; D014501:Uranium
D004391:Dust; D014501:Uranium; D011886:Radon