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

Abstract

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.