Zhenxing Chi

Dimethyl phthalate (DMP) can enter the human body and be absorbed into the bloodstream to produce monomethyl phthalate (MMP). MMP in the environment can also enter the bloodstream. However, little is known about the toxicity of the phthalate metabolite MMP in most organisms. In this study, the erythrocyte toxicity of MMP and a preventive approach were investigated using Sprague–Dawley (SD) rats as the model animal under MMP concentrations of 5–250 mg/kg (sub-chronic exposure in vivo) and 1.25–100 μg/mL (acute exposure in vitro). The experimental results indicate that the interaction of MMP with erythrocytes caused oxidative damage, which decreased the number of red blood cells and the hemoglobin content and increased the content of methemoglobin and the iron release of hemoglobin in rat blood. However, the above results were not observed when MMP directly interacted with hemoglobin. The antioxidants vitamin C and vitamin E improved the above blood indicators in rats. The results of this study provide certain theoretical guidance for the evaluation of the potential risks of phthalate metabolites.

Silver ions (Ag⁺) can be released by silver nanoparticles (AgNPs) which are widely used in diverse fields. Ag⁺ can exist inside cells to produce cytotoxicity. This report uses spectroscopic methods to reveal the interactions between Ag⁺ and bovine hemoglobin (BHb). The results of the quenching rate constant (K_q) and the fluorescence lifetime detection showed that the quenching mechanism of BHb by Ag⁺ was static. Thermodynamic investigations indicated that Ag⁺ can interact with BHb with one binding site to form complex mainly through van der Waals interactions and hydrogen bonds. The UV-vis absorption and synchronous fluorescence spectra showed that Ag⁺ changed the conformation of BHb, which may affect protein functions. This research is favorable for understanding the molecular toxic mechanism of Ag⁺ in vivo.