A microdialysis method to measure in vivo hydrogen peroxide and superoxide in various rodent tissues.

Reactive oxygen species (ROS) play a critical role in cell signaling and disease pathogenesis. Despite their biological importance, assessment of ROS often involves measurement of indirect byproducts or measurement of ROS from excised tissue. Herein, we describe a microdialysis technique that utilizes the Amplex Ultrared assay to directly measure hydrogen peroxide (HO) and superoxide in tissue of living, anesthetized rats and mice. We demonstrate the application of this methodology in the penis, adipose tissue, skeletal muscle, kidney, and liver. We provide data demonstrating the impact of important methodological considerations such as membrane length, perfusion rate, and time-dependence upon probe insertion. In this report, we provide a complete list of equipment, troubleshooting tips, and suggestions for implementing this technique in a new system. The data herein demonstrate the feasibility of measuring both in vivo HO and superoxide in the extracellular environment of various rodent tissues, providing a technique with potential application to a vast array of disease states which are subject to oxidative stress.