Quantitative Assessment of Tumor Blood Flow in Mice after Treatment with Different Doses of an Antiangiogenic Agent with Contrast-enhanced Destruction-Replenishment US

Abstract

To quantify tumor blood flow by using contrast material-enhanced destruction-replenishment ultrasonography (US) to evaluate tumor response to different doses of an agent for antiangiogenic treatment in hepatoma-bearing mice, with histologic measurements of microvascular density (MVD) as the reference standard. Experiments were approved by the regional animal care committee. Mice bearing subcutaneous H22 hepatoma were treated with different doses of thalidomide, 100 mg/kg in group B and 200 mg/kg in group C. Group A (control group) was treated with 0.5% carboxylmethylcellulose. Treatment groups and the control group included 10 mice each. Contrast-enhanced US was used to evaluate the percentage of nonenhanced area, and contrast-enhanced destruction-replenishment US was used to evaluate tumor blood flow. Tumor blood flow was compared with measurements of MVD. Comparisons were made by using one-way analysis of variance and the post hoc least significant difference test for multiple comparisons. Contrast-enhanced gray-scale US showed significant increases in the percentage of nonenhanced area in group C (mean, 10.56% ± 7.25 [standard deviation]), as compared with groups A (mean, 2.40% ± 3.12; P = .004) and B (mean, 3.75% ± 5.55; P = .012). Contrast-enhanced destruction-replenishment US showed significant decreases of tumor blood flow in groups B and C, as compared with group A (P = .003 and P < .001, respectively), and the blood flow in group C was significantly lower than that of group B (P = .01). Immunohistochemical analysis revealed significant decreases of MVD in groups B and C, as compared with MVD in group A (P = .002 and P < .001, respectively); however, there was no significant difference in MVD between groups B and C (P = .21). Quantification of tumor blood flow by using contrast-enhanced destruction-replenishment US shows the potential to guide drug dosage during antiangiogenic therapy.