Effects Of Antiangiogenesis Chemotherapy With Cyclophosphamide Inhibiting The Formation Of Microvessel In Murine Subcutaneous Sarcoma

OBJECTIVES: To observe the effect and mechanism of cyclophosphamide (CTX) antiangiogenesis chemotherapy (ACT) on the forming of microvessel in the mice bearing subcutaneous sarcoma caused by S180 cells and to determine an optimum antiangiogenic dose for CTX. METHODS: S180 cells were implanted into the right posterior lateral flank of 4-5weeks old female KunMing mice. Different chemotherapeutics of CTX were initiated 5-6 days after inoculation, just as tumor volumes reached 100mm3 (6mm in diameter). 1. Experiment of determining an optimum antiangiogenic dose for CTX: The mice bearing tumor were randomly divided into six groups (A1, A2, A3, A4, A5 and A6 group), and CTX (twice weekly for 3 weeks) was administrated to each group, the total dosage were 2, 1, 1/2, 1/5, 1/10 and 1/20 times consistent with the maximum tolerated dose (MTD, 450mg/Kg), respectively. After administration, the weight of mice and the volume of tumors were measured, and the microvessel densities of the sarcoma were measured by immunohistochemical method. 2. Experiment of CTX inhibiting the formation of microvessel: The mice bearing tumor were randomly divided into 3 groups: A, ACT group; B, CTX standard chemotherapy group; C, saline control group. After administration, the microvessel densities of the sarcoma and the mean tumor inhibition rates were measured. The morphological changes of vascellum endothelial cell and tumor cell were observed at the 4th and 21st day. The VEGF serum levels were measured by ELISA method at four times: before administration, 8, 15 and 21 day after starting treatment. RESULTS: 1. About the Experiment of determining an optimum antiangiogenic dose for CTX: the mean tumor inhibition rates were ( 88.4%±3.3% ),( 88.0%±6.1% ),( 83.5%±6.6% ),( 80.4±7.6% ) and 0.4%±29.1% ) And the mean increase in body weight were ( -2.4±2 )g,(4.9±3.4)g,(6.7±2.3)g,(6.6±1.7)g,(6.0±2.3)g and (8.6±2.5)g in group A1, A2, A3, A4, A5 and A6 group, respectively. 2. About the Experiment of CTX inhibiting the formation of microvessel: the mean tumor inhibition rates were (86.7%±5.4%), (90.3%±4.0%) in group A and B respectively. Immuno- histochemical results showed that the MVD in group A, B and C were (7.1±1.7),(14.8±3.1) and (15.7±3.1)mm2,espectively. And at the 21st day after administration, the VEGF serum levels were (21.2±7.6), (41.0±14.4) and (35.2±13.9)pg/ml in group A, B and C, respectively. CONCLUSION: Decreasing the VEGF level and impairing the endothelial cell of the new forming vascular is a potential mechanism for ACT to inhibit the formation and growth of the murine subcutaneous sarcoma by inhibiting the microvesel formation. Antiangiogenesis chemotherapy with CTX can inhibit the microvessel formation in a specific concentration range.