Radiation induced oxidative stress: II studies in liver as a distant organ of tumor bearing mice.
Since the radiation dose tolerance of normal tissues/organs away from the site of tumor influences the success of radiation therapy of cancer, and antioxidant status is likely to be one of the factors to determine the tolerance; the radioresponse of antioxidant enzymes has been examined in the liver as a representative distant organ in the tumor-bearing mice. Swiss albino male mice (7-8 weeks old) with Ehrlich solid tumor in the thigh pad were irradiated with different doses of gamma-radiation (0-9 Gy) at a dose rate of 0.0153 Gy/s and the specific activities of enzymes involved in the free radical metabolism were determined in the liver. Except GST, the activities of SOD, DTD and Gly I as well as the GSH content were found to be higher in the liver of tumor-bearing mice compared to the non-tumor bearing mice. The catalase activity progressively decreased with dose in both the groups of mice. However, the activity was relatively higher in the liver of tumor- bearing mice than the control. Thus, the radioresponse of antioxidant enzymes seemed to be significantly different in the liver of tumor-burdened mice compared to controls. The enhanced activities might be due to relatively more damage caused by radiation. The higher levels of NO* and peroxidative damage in the liver of tumor-bearing mice probably suggest this possibility. These findings of the present work might have some serious implications as the increased radiation-damage of the distant normal organs (due to tumor burden) is likely to adversely affect the therapeutic gain.
Agrawal
A
A
Free Radical Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.
Chandra
D
D
Kale
R K
RK
D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002286:Carcinoma, Ehrlich Tumor / Q000201:enzymology / Q000378:metabolism* / Q000532:radiotherapy*; D002374:Catalase / Q000378:metabolism; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays / Q000009:adverse effects*; D005978:Glutathione / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D007791:Lactoylglutathione Lyase / Q000378:metabolism; D008099:Liver / Q000201:enzymology / Q000378:metabolism* / Q000528:radiation effects*; D008297:Male; D051379:Mice; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000378:metabolism; D009368:Neoplasm Transplantation; D009569:Nitric Oxide / Q000378:metabolism; D018384:Oxidative Stress / Q000528:radiation effects*; D011878:Radiotherapy / Q000009:adverse effects; D013482:Superoxide Dismutase / Q000378:metabolism; D014916:Whole-Body Irradiation
D000975:Antioxidants; D009569:Nitric Oxide; D007770:L-Lactate Dehydrogenase; D002374:Catalase; D013482:Superoxide Dismutase; D016660:NAD(P)H Dehydrogenase (Quinone); D005982:Glutathione Transferase; D007791:Lactoylglutathione Lyase; D005978:Glutathione