A comparison of the mutagenic and apoptotic effects of tritiated water and acute or chronic caesium-137 gamma exposure on spleen T lymphocytes on normal and p53-deficient mice.
OBJECTIVE
This study was carried out to compare the mutagenic effects on spleen T lymphocytes of mice exposed to tritiated water (HTO) and chronic or acute (137)Cs gamma irradiation.


METHODS
p53 wild type (p53(+/+)) and p53 null type (p53(-/-)) mice were exposed to a total dose of 3 Gy of HTO, chronic (137)Cs and acute (137)Cs.


RESULTS
In spontaneous T-cell receptor (TCR) variant fractions and fractions following exposure to HTO, chronic (137)Cs and acute (137)Cs, TCR variant fractions in p53(+/+) mice were 5.9 x 10(-4), 9.8 x 10(-4), 6.4 x 10(-4) and 20.1 x 10(-4), respectively. In contrast, those fractions were increased in p53(-/-) mice to 11.2 x 10(-4), 18.8 x 10(-4), 15.7 x 10(-4) and 31.3 x 10(-4), respectively. The frequency of apoptotic cells of the spleen 12 h after HTO injection increased to 5.0% in p53(+/+) mice, but did not increase at all in p53(-/-) mice.


CONCLUSIONS
When compared on the basis of induced TCR variant fractions in p53(-/-) mice, HTO (7.6 x 10(-4)) was 1.7 times more mutagenic than chronic (137)Cs (4.5 x 10(-4)), but 2.6 times less mutagenic than acute (137)Cs gamma irradiation (20.1 x 10(-4)).
Umata
Toshiyuki
T
Radioisotope Research Center, University ofOccupational and Environmental Health, Japan. umata@med.uoeh-u.ac.jp
Kunugita
Naoki
N
Norimura
Toshiyuki
T
D000208:Acute Disease; D000818:Animals; D017209:Apoptosis / Q000502:physiology / Q000528:radiation effects*; D002588:Cesium Radioisotopes / Q000009:adverse effects*; D002908:Chronic Disease; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays / Q000009:adverse effects*; D051379:Mice; D008810:Mice, Inbred C57BL; D009153:Mutagens / Q000009:adverse effects; D011833:Radiation Injuries, Experimental; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D013154:Spleen / Q000276:immunology* / Q000473:pathology / Q000528:radiation effects; D013601:T-Lymphocytes / Q000276:immunology / Q000473:pathology / Q000528:radiation effects*; D014316:Tritium / Q000009:adverse effects*; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency* / Q000235:genetics
D002588:Cesium Radioisotopes; D009153:Mutagens; D011948:Receptors, Antigen, T-Cell; D016159:Tumor Suppressor Protein p53; D014316:Tritium