Effects of low-dose radiation on tumor growth, erythrocyte immune function and SOD activity in tumor-bearing mice.
BACKGROUND
Activating on mammalian and human body LDR is thought to induce adaptive response, enhance immune function and increase anti-tumor ability. This study was designed to assess the effect of low-dose radiation on tumor growth and on erythrocyte immune function and superoxide dismutase (SOD) activity in tumor-bearing mice.


METHODS
Male Kunming mice were subcutaneously implanted with S180 sarcoma cells in the right inguen to create an experimental in situ animal model. Six hours before implantation, the mice were given 75 mGy X-ray radiation, over the body. Tumor size was observed 5 days later while tumor volume was calculated every other day, allowing for the creation of a graph depicting tumor growth. Fifteen days after implantation, the mice were killed to measure tumor weight and observe the necrotic areas and the location of tumor-infiltrating lymphocytes (TILs). Erythrocyte immune function and SOD activity were also determined.


RESULTS
Mice pre-exposed to low-dose radiation had a lower tumor formation rate than did those receiving no radiation (P < 0.05). Tumor growth was significantly lower in the mice pre-exposed to low-dose radiation; after 15 days, the average tumor weight in the mice pre-exposed to low-dose radiation was also lower (P < 0.05). Areas of tumor necrosis and infiltration of TILs were larger in the low-dose radiation group than in the non-radiation group. Erythrocyte immune function and SOD activity were higher in the low-dose radiation group than in the non-radiation group (P < 0.05).


CONCLUSIONS
Low-dose radiation can markedly increase the anti-tumor ability of an organism and improve erythrocyte immune function and red blood cell SOD activity as well, suggesting that low-dose radiation might be useful in the clinical treatment of cancer.
Yu
Hong-sheng
HS
Department of Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Song
Ai-qin
AQ
Lu
Yan-da
YD
Qiu
Wen-sheng
WS
Shen
Fang-zhen
FZ
D000818:Animals; D001706:Biopsy; D004912:Erythrocytes / Q000201:enzymology / Q000276:immunology / Q000528:radiation effects*; D005609:Free Radicals; D008297:Male; D051379:Mice; D012510:Sarcoma 180 / Q000097:blood / Q000473:pathology / Q000532:radiotherapy*; D013482:Superoxide Dismutase / Q000097:blood*
D005609:Free Radicals; D013482:Superoxide Dismutase