Glutathione Peroxidase-Activatable Two-Photon Ratiometric Fluorescent Probe for Redox Mechanism Research in Aging and Mercury Exposure Mice Models.

Solid evidence confirms that glutathione peroxidase (GPx) is a kind of vital protease in the first-line antioxidant defense system and participates in regulation of redox homeostasis as well as the pentose phosphate pathway. However, the current methods cannot achieve real-time and in situ visualization studies of GPx. In addition, GPx is highly reactive and susceptible to external interference, and there is rare research for exploring the roles of GPx under environmental factor exposure. Herein, we report a novel two-photon ratiometric fluorescent probe (TP-SS) for GPx detection for the first time. Using TP-SS, we explore the reversible catalytic cycle and the antioxidant mechanisms of GPx/GSH redox pool in aging and mercury exposure models. We detect the concentration fluctuation of GPx in aging and mercury exposure mice models. Also, we perform GPx detection in deep brain tissue and the imaging depth up to 100 μm. We believe that the novel two-photon ratiometric fluorescent probe TP-SS can facilitate the development of GPx-targeting tools and offer great advances in exploring the physiological/pathological functions of GPx.