Effect of fractionated radiotherapy of transplanted hepatocellular carcinoma on the splenic immune cells in mice / 中华放射医学与防护杂志

ABSTRACT

Objective@#To investigate the effect of fractionated radiotherapy on the immune system of mice with subcutaneously transplanted hepatocellular carcinoma.@*Methods@#Logarithmic growth of mouse hepatocellular carcinoma cells Hepa 1-6 were inoculated subcutaneously on the right side of C57BL/6 J mice (1×107 cells /mice). The tumor-bearing mice were randomly divided into control group (Ctrl) and irradiation group (IR), 20 mice in each group. Additionally, 10 healthy mice were set as normal control group. Local fractionated X-ray irradiation of 8 Gy×3 fraction was given to the subcutaneous tumors, and the dose rate was 0.883 Gy/min. At 7 and 14 d after irradiation, the tumor organ index, spleen organ index, spleen pathological changes, and splenic T lymphocyte subsets, B lymphocyte subsets, and NK cells were detected.@*Results@#Compared with Ctrl, at 7 and 14 d after irradiation, the tumor organ index decreased (t=4.649, 26.34, P<0.05), and the percentage of NK cells increased significantly (t=3.952, 3.633, P<0.05). The percentages of CD3+ , CD4+ , CD3+ CD4+ lymphocytes and the ratio of CD4+ /CD8+ lymphocyte decreased at 7 d after irradiation (t=3.193, 3.656, 3.219, 2.641, P<0.05), and the percentage of CD3+ lymphocyte decreased at 14 d after irradiation (t=3.031, P<0.05). But after irradiation, there were no significant changes in spleen organ index, B lymphocyte, CD3+ CD4+ lymphocyte and CD8+ lymphocyte.@*Conclusions@#Local hepatoma radiotherapy causes imbalance of lymphocytes in distal spleen of mice and hence reduces immunity, which provides a novel mechanism of radiological immunity damage.