Effect of pre-exposure to beta rays of tritium on some biochemical parameters measured in organs of rats subsequently irradiated with fast neutrons.
The experiment examined biological responses produced by combined sequential exposure to low-level tritium contamination, followed by challenging irradiation with fast neutrons. Modifications of endogenous antioxidant potential of different organs in rats were discussed in relation to tissue radiosensitivity. Rats pre-contaminated to 7 cGy and 35 cGy have been additionally irradiated to 1 Gy with fast neutrons. Lipid peroxide level was determined in liver, kidney, small intestine, spleen, bone marrow, and plasma. Reduced glutathione (GSH) level and glucose-6-phosphate dehydrogenase (G6PDH) activity were determined in erythrocytes. An in vitro thymidine uptake assay was performed in isolated bone marrow cells. The lipid peroxide level decreased significantly only in liver and kidney from rats pre-exposed to 35 cGy. For small intestine and spleen, tissues of comparatively higher radiosensitivity, no induced radioprotection was observed, as reflected in the homeostasis of the lipid peroxides. The same behavior was observed in bone marrow, the most radiosensitive tissue studied. However, the bone marrow thymidine-incorporation assay revealed a possible adaptive-type reaction in rats pre-exposed to 35 cGy. We conclude that for radiosensitive tissues pre-exposure to chronic low doses of low linear energy transfer (LET) irradiation has no protective effect on their antioxidant status, whereas a protective effect is observed in radioresistent tissues.
Department of Health and Environmental Physics, Horia Hulubei Institute of Physics and Nuclear Engineering, Bucharest-Magurele, Romania. ipetcu@ifin.nipne.ro
Ileana
I
Petcu
Nicoleta
N
Moisol
Diana
D
Savu
B
B
Constantinescu
D000222:Adaptation, Physiological; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001610:Beta Particles / Q000009:adverse effects; D004912:Erythrocytes / Q000378:metabolism / Q000528:radiation effects; D005214:Fast Neutrons / Q000009:adverse effects*; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D015227:Lipid Peroxidation / Q000528:radiation effects; D008297:Male; D008660:Metabolism / Q000528:radiation effects*; D010084:Oxidation-Reduction; D051381:Rats; D017208:Rats, Wistar; D012062:Relative Biological Effectiveness; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D013936:Thymidine / Q000378:metabolism; D014316:Tritium / Q000009:adverse effects
D000975:Antioxidants; D017392:Thiobarbituric Acid Reactive Substances; D014316:Tritium; D005954:Glucosephosphate Dehydrogenase; D005978:Glutathione; D013936:Thymidine