Figure 1

Number of TRACP+ multinuclear cells and the activity of bone resorption in pit assay. Rat bone cells were cultured for 48 hours with no added substances (CONTROL), vascular endothelial growth factor A (VEGF ng/ml), endostatin (ENDO μg/ml) or both VEGF-A and endostatin (VEGF ng/ml +ENDO μg/ml). (A) Survival rate of osteoclasts after different treatments was measured by counting the numbers of TRACP-positive cells with two or more nuclei indicating osteoclasts. No significant differences in the number of osteoclasts could be seen. (B) Osteoclastic bone resorption could be visualized with WGA-lectin stain and total resorbed areas from the different cultures were measured. VEGF-A treatment induced a clear stimulus, whereas endostatin caused no effect on the resorbed area. Addition of both VEGF-A and endostatin caused a statistically significant decrease in the total resorbed area when compared to the VEGF-A-induced resorption. (VEGF ng/ml, ENDO μg/ml)