Currently no clinical tool exists that measures the degree of ischemic injury incurred in tissue and assesses tissue function following transplantation. In response to this clinical problem, we explore optical spectroscopy to quantitatively assess ischemic injury. In our method we monitor the autofluorescence intensities under excitation suitable to excite specific tissue fluorophores. Specifically, a first excitation probes NADH, a biomolecule known to
change its emission properties depending on the tissue's metabolic state. A second excitation is used to mainly probe tryptophan, a biomolecule expected to be minimally affected by metabolism. We postulate that the ratio of the two autofluorescence signals can be used to monitor tissue behavior during ischemia and reperfusion. To evaluate this approach, we acquire autofluorescence images of the injured and contralateral control kidney in vivo in a rat model under excitation at both wavelengths during injury and reperfusion. Our results indicate that this approach has the potential to provide real-time monitoring of organ function during transplantation.
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