UV-aged polystyrene nanoplastics aggravate intestinal barrier damage by overproduction of ROS

UV irradiation significantly alters nanoplastics (NPs) physicochemical properties, thus affecting their biological toxicity. This study is the first to assess the influence of virgin and UV-aged polystyrene NPs (v-PS NPs, a-PS NPs) on the intestinal barrier of ICR mice. We found that a-PS NPs can cause more severe intestinal barrier damage compared with v-PS NPs. The reason may be attributed to that a-PS NPs produced more ROS in intestinal tissue. Moreover, the strong oxidizing property of hydroxyl radicals (center dot OH) generated from the a-PS NPs can damage cell membranes through lipid peroxidation, thereby leading to a low clearance rate of center dot OH due to the impaired intestinal tissue function, in turn, causing more ROS to accumulate and inducing severe oxidative damage. This research underscores the crucial role of center dot OH in mediating oxidative damage from UV-aged nanoparticles, emphasizing the need to consider environmental factors in assessing NPs toxicity.