Studying mercury and polymethyl methacrylate joint effects on endogenous hydrogen polysulfides via fluorescence...

Heavy metal ions and micro(nano)plastic pollution have attracted increasing attention. However, their toxicological effects on endogenous reactive species at molecular level are unclear, especially their joint effects. Hence, two typical environmental poisons, mercury (Hg²⁺) and polymethyl methacrylate (PMMA), posing significant risks to both human health and ecosystems, are selected as pollution models for studying joint effects. Hydrogen polysulfides (H₂S_n, n > 1) play crucial roles in removing oxidants and intracellular electrophilic reagents, involved in regulating intracellular redox state. The understanding of its precise biological role and intricate mechanism action remains limited, especially suffering from exogenous environmental stress. Herein, we have developed a novel H₂S_n- responsive fluorescence probe P-Y with outstanding performance. Moreover, probe P-Y could image endogenous H₂S_n levels in cells, and was successfully applied for monitoring the fluctuations of endogenous H₂S_n levels to investigate their effects on redox homeostasis under Hg²⁺ and PMMA single and combined exposure. This study provided imaging evidences and an absorbing insight for understanding H₂S_n function under Hg²⁺ and PMMA single and joint effects in living organisms.