The mechanism of polystyrene nanoplastics hepatotoxicity in zebrafish (Danio rerio)

The mass production of plastics and improper disposal of plastic waste has led to their widespread presence in the ecosystem. Plastics entering the natural environment degrade into irregularly shaped and differently sized nanoplastics (NPs), exacerbating global pollution. The research object to study toxic mechanisms of the liver polystyrene nanoplastics (PS NPs) of zebrafish, providing key scientific insights for the environmental risk assessment of NPs. The zebrafish were exposed to different concentrations with a particle size of 100 nm PS NPs containing Eu, and the accumulation of nanoplastics in each tissue/organ was quantified. The mechanism of liver toxicity of nanoplastics to zebrafish was explored. Where the mass of PS NPs was linearly related to the mass of Eu with R 2 = 0.999. PS NPs were accumulated in gills, ovaries, liver, spleen, intestine, kidney, skin, muscle and brain. The top three accumulations were: intestine > gills > liver. The histopathological analysis of liver indicated that 0.1 mg/L and 1 mg/L PS NPs caused increased liver inflammation. 0.1 mg/L PS NPs significantly increased the activity of SOD and the content of ROS and MDA in liver. 1 mg/L PS NPs significantly increased the activity of SOD, CAT and GSH and the content of MDA in liver, while significantly decreased the content of ROS. These results will improve the appreciation of the cumulative impact of PS NPs and the mechanism of toxicity on target organs in organisms.