Hepatotoxicity Induced By Exposure Of Microplastics-Cd

Microplastic pollution is one of the global environmental problems that have attracted much attention in recent years.However,there is still a lack of research on the toxic effects and mechanism of microplastics on higher mammals.The complex toxicity of microplastics and their adsorptive pollutants as well as the toxic effect and mechanism after environmental transformation are scientific problems that need to be solved urgently in the environmental toxicological evaluation of microplastics.In this paper,the toxicity effect of single polystyrene microplastics(PS-MPs)on human hepatocellular carcinoma cell lines was investigated by using the methods of cell biology,molecular biology and material characterization.The adsorption capacity of PS-MPs to cadmium was determined under the natural adsorption state,and the toxic effect caused by exposure of liver cell lines to PS-MPs after cadmium adsorption(PS-Cd complex)was investigated and its toxic mechanism was discussed.At the same time,the transformation toxicity of microplastics was investigated after being treated with simulated gastric juice.AB,MTT,JC-1 and ROS methods were used to investigate the toxic effects of exposure to single PS-MPs or cadmium and PS-Cd complex on human hepatocytes.The results showed that single PS-MPs did not incur significant toxic effects on cell activity and mitochondria,but it could induce oxidative stress in cells.The toxic effect of PS-Cd complex was enhanced when exposed to PS-MPs alone,but decreased when exposed to cadmium alone,indicating that part of cadmium was adsorted on microplastics,and the bioavailability of cadmium was reduced and the toxic effect was decreased.Further by using various ferroptosis inhibitors,MTT method and microscopic observation showed that the addition of ferroptosis inhibitors could attenuate the toxic effect of individual PS-MPs or cadmium and PS-Cd complex exposure on human hepatocytes,revealing that ferroptosis may be one of the mechanisms causing the toxic effect.Through SEM,Zetasizer,FT-IR and XPS characterization,it was found that polystyrene microplastics could be degraded similar to the results of cadmium incubation.At the same time,AB method,ROS method,LDH method,MDA method and flow cytometry were used,and it was found that compared with untreated microplastics,the treated microplastics in simulated gastric juice significantly reduced cell activity,increased intracellular ROS level,membrane permeability and membrane lipid peroxidation,and promoted cell apoptosis.According to the above results,exposure of PS-MPs or cadmium and PS-Cd complex alone can produce toxic effects on hepatocytes,and ferroptosis may be one of the mechanisms causing the toxic effects.The physical and chemical characteristics of the microplastics were changed and the toxic effect was enhanced after simulated gastric juice treatment.This paper provides a theoretical basis for evaluating the toxic effect and mechanism of microplastics after absorbing heavy metals,and provides data support for predicting the toxic effect of microplastics after chemical transformation.