Primary tumorectomy promotes angiogenesis and pulmonary metastasis in osteosarcoma-bearing nude mice

PURPOSE: To investigate the effect of primary tumorectomy on angiogenesis and pulmonary metastasis in osteosarcoma-bearing nude mice. METHODS: Osteosarcoma was introduced to nude mice via subcutaneous injection of MG-63 cells. One hundred and eighty osteosarcoma-bearing mice were used equally in 3 parallel experiments. The effect of tumorectomy (TR) on the expression of vascular endothelial growth factor (VEGF) and endostatin was investigated by ELISA. Meanwhile, the effect on angiogenesis was evaluated by Matrigel plug assay, and pulmonary metastasis assessed by calculating the metastatic foci. Sham-operation (SO) and untreated (UT) groups served as controls. RESULTS: The VEGF (TR: 79.55 ± 7.82 pg/mL vs. SO: 110.01 ± 5.69 pg/mL, UT: 123.50 ± 10.41 pg/mL; p < 0.01) and endostatin (TR: 47.09 ± 6.22 ng/mL vs. SO: 117.64 ± 7.39 ng/mL, UT: 126.73 ± 6.55 ng/mL; p