The long term goal of this research is to develop quantitative optical imaging methods for tissue bioenergetic studies. In Phase I, a videofluorometer with high spatial resolution was developed that produces NADH fluorescence images compensated for internal absorption due to blood volume changes. This device was used to evaluate both local and global ischemia in buffer and blood perfused rat hearts. Initial studies performed during Phase I demonstrate that an enhanced instrument can produce complimentary images of tissue oxygen tension using unique palladium porphyrins. Phase II will consist of: (1) upgrading the videofluorometer to obtain sequential NADH and palladium porphyrin emission images, (2) synthesizing appropriate palladium porphyrins and evaluating their utility for in vivo use, (3) developing software to produce tissue oxygen concentration images, and (4) calibrate and evaluate the use of this enhanced videofluorometer in studies of models of hypoxia and ischemia. This dual function videofluorometer in Phase II will allow rapid, sequential imaging of tissue metabolism and oxygen concentration and thus have much greater utility in spatially quantifying tissue metabolism and oxygen supply/demand for research purposes and potential clinical uses than current devices.
