Effects of paclitaxel in combination with ionizing radiation on angiogenesis in the chick embryo chorioallantoic membrane. A radiobiological study.

PURPOSE

To investigate the combined effects of paclitaxel and single or fractionated doses of ionizing radiation on the angiogenesis process, using as a model the chick embryo choriallantoic membrane (CAM).

MATERIAL AND METHODS

Experiments were performed on 9-day CAM, when membranes were irradiated with various single or fractionated doses of X-rays, either alone or in combination with paclitaxel (6.4 micro g/disk).

RESULTS

Single doses of irradiation (5, 10, or 15 Gy) produced a significant antiangiogenic effect, which was not dose-dependent. Fractionated doses of X-rays (two doses of 2.5, 5, or 7.5 Gy, each 12 h apart) exerted a dose-dependent reduction of the vascular density index. Paclitaxel was not shown to provoke radiosensitization in this model, i. e., to inhibit angiogenesis of the 9-day CAM.

CONCLUSION

These data confirm that the CAM system can be conveniently and properly used for radiobiological studies and indicate that paclitaxel in combination with ionizing radiation does not inhibit further angiogenesis in the system used.