A “hydroxyl radicals standard” for evaluating the efficacy of anti-asthma drugs by using a two-photon NIR optical sensor

Asthma is a common chronic inflammatory disease of the airways and a condition closely associated with oxidative stress. However, the lack of effective biomarkers and non-invasive real-time monitoring tools remains a great challenge for the early diagnosis and therapy of asthma. Hydroxyl radicals represent a key reactive oxygen species in biological systems, and therefore the change of hydroxyl radical level may be observed to be elevated in asthmatic mice. To verify this conjecture, in this paper, we designed the first two-photon (TP) near-infrared (NIR) fluorescent probe to be used with high selectivity for monitoring the fluctuating changes of hydroxyl radicals. More importantly, using this new probe, we have successfully observed the changes of hydroxyl radicals during asthma by visualization means for the first time. Immediately following the imaging experiments on mice, we also found that the therapeutic effect of using the combination of budesonide and terbutaline administration in asthmatic mice was effective than what was achieved by the administration of budesonide or terbutaline alone. These findings suggest that this probe has the potential to be a powerful tool for future asthma diagnosis and assessment of the therapeutic effect of asthma co-administration. Notably, it is expected to establish a "hydroxyl radicals standard" for evaluating the efficacy of anti-asthma drug therapy by using fluorescence imaging techniques.