Abstract: In this study, the availability of specific monoclonal antibodies capable of blocking VEGF-induced angiogenesis in vivo allowed us to test the hypothesis directly. The aim of our study was to observe the inhibition of growth of osteosarcoma by anti-VEGF monoclonal antibody through animal experiment. We also investigate the effect of anti-VEGF antibody on microvessel density in tumors through histological method. Twenty-three female BALB/C nude mice were used in this study. OS-732 osteosarcoma cells were injected into the armpit subcutaneous part(1070/mL for each mouse). The nude mice are divided into four groups randomly(A, B, C, and D). The anti-VEGF monoclonal antibody was injected into the six mice of group A at the next day of the osteosarcoma cell-injection. Two weeks later, the antibody was injected into the six mice of group B. PBS was injected into the six of group C and nothing to the five of group D at the same time with group A. The single application of the antibody was 200 μg for each mouse three times weekly for three weeks. The mice of group A and C were killed four weeks later and group B and D six weeks later. Every mouse was anatomized and the tumor was taken out for a pathological slice. The tumor size and counted the microvessel density were meesured. Comparisons of the results with and without the treatment were performed using a Student T-test. A value of (P<0.05 was considered significant. The tumor growth was significantly inhibited only when the anti-VEGF antibody administration was started immediately after tumor cell inoculation(group A)but not when such treatment was initiated two weeks later(group B), when the tumors were already established. When comparing the microvessel density, there were no significant differences between the four groups. In summary, our results demonstrated, for the first time, that the incipient growth of osteosarcoma could be inhibited significantly by anti-VEGF antibody. The anti-VEGF antibody may be useful for the prevention and clinical treatment of the metastasis focus of osteosarcoma.

Key words: VEGF|Anti-VEGF antibody|osteosarcoma