ABSTRACT
Objective To study the impact of local fractionated irradiation on lung metastasis in H22-bearing mice, and to explore its mechanism involved. Methods Subcutaneous transplantation tumor model bearing with H22 was established. Mice were divided into three groups as healthy control, tumor control and irradiation groups. The size of subcutaneous tumors was measured and lung metastasis was observed. The expressions of PCNA, VEGF and MVD were detected immunohistochemically. The plasma levels of CD4 and CD8 were determined by using flow cytometry. Results The tumor size in irradiated group was smaller than that in tumor control group. The tumor inhibition rate in irradiated group was 30%.Lung metastasis in irradiated group was more severe than that in tumor control group (x2 = 8.31,4.48,9. 60, P＜ 0.05 ). The expressions of PCNA, VEGF and MVD in two groups were statistically different( t =23.78,-2.47, -6.43, P ＜ 0. 05). The levels of CD4 and CD8 in irradiated group were statistically different compared to healthy control group ( t = 4. 72 and 3.31, P＜ 0.05 ). Conclusions For the H22 model, radiation might inhibit the local transplantation tumor, but increase the risk of lung metastasis.