Oxygenation and blood flow in tumors treated with hydralazine: evaluation with a novel luminescence-based fiber-optic sensor.

Two optical methods were used simultaneously to evaluate the effect of a vasoactive drug hydralazine on oxygenation and blood flow in SA-1 tumors in A/J mice. A novel luminescence-based optical sensor (OxyLite instrument, Oxford Optronix, UK) was used to monitor partial pressure of oxygen (pO2) in tumors. Laser Doppler flowmetry was used to assess relative blood perfusion in tumors. Measurements were performed continuously on anesthetized mice before and after i.v. injection of hydralazine at a dose of 2.5 mg/kg. Hydralazine reduced pO2 on average by 80% minutes after injection. Our results indicate that hydralazine could be used to improve the antitumor effectiveness of hypoxic cell-specific therapies. We demonstrated that both optical methods can be used successfully to detect changes in blood perfusion and oxygenation in tumors after blood flow-modifying treatments. Some aspects of pO2 measurement with the new luminescence-based method require further investigation.