Polystyrene nanoplastics with different functional groups and charges have different impacts on type 2 diabetes

Background: Increasing attention is being paid to the environmental and health impacts of nanoplastics (NPs) pollution. Exposure to nanoplastics (NPs) with different charges and functional groups may have different adverse effects after ingestion by organisms, yet the potential ramifications on mammalian blood glucose levels, and the risk of diabetes remain unexplored.

Results: Mice were exposed to PS-NPs/COOH/NH₂ at a dose of 5 mg/kg/day for nine weeks, either alone or in a T2DM model. The findings demonstrated that exposure to PS-NPs modified by different functional groups caused a notable rise in fasting blood glucose (FBG) levels, glucose intolerance, and Insulin resistance in a mouse model of T2DM. Exposure to PS-NPs-NH₂ alone can also lead the above effects to a certain degree. PS-NPs exposure could induce glycogen accumulation and hepatocellular edema, as well as injury to the pancreas. Comparing the effect of different functional groups or charges on T2DM, the PS-NPs-NH₂ group exhibited the most significant FBG elevation, glycogen accumulation, and Insulin resistance. The phosphorylation of Akt and FoxO1 was found to be inhibited by PS-NPs exposure. Treatment with SC79, the selective Akt Activator was shown to effectively rescue this process and attenuate T2DM like lesions.

Conclusions: Exposure to PS-NPs with different functional groups (charges) induced T2DM-like lesions. Amino-modified PS-NPs cause more serious T2DM-like lesions than pristine PS-NPs or carboxyl functionalized PS-NPs. The underlying mechanisms involved the inhibition of P-AKT/P-FoxO1. This study highlights the potential risk of NPs pollution on T2DM, and provides a new perspective for evaluating the impact of plastics aging.

AKT; FoxO1; Functional groups; Nanoplastics; Type 2 diabetes.