A Study on Hypoxia Susceptibility of Organ Tissues by Fluorescence Imaging with a Ratiometric Nitroreductase Probe
Sourav Sarkar, Hyori Lee, Hye Gun Ryu, Subhankar Singha, Yeong Mi Lee, Ye Jin Reo, Yong Woong Jun, Kyeong Hwan Kim, Won Jong Kim, Kyo Han Ahn
Abstract
Hypoxia, a condition of oxygen deficiency in tissues, features various diseases including solid tumor. Under hypoxia, several reductases such as nitroreductases are elevated. Based on this fact, we have investigated an indirect way to assess the hypoxia susceptibility of different organ tissues (mouse lung, heart, spleen, kidney, and liver) by detecting nitroreductase present within. Among the organs, the kidney showed a notable susceptibility to hypoxia, which was due to the renal medulla, not due to the renal cortex, as observed by ratiometric fluorescence imaging with a probe. The probe features ratiometric signaling, NIR-emitting, two-photon absorbing, and pH-insensitive emission properties, offering a practical tool for studying the nitroreductase activity and, furthermore, hypoxia-associated biological processes.