Lactic acid bacteria reduce polystyrene micro- and nanoplastics-induced toxicity through their bio-binding capacity and gut environment repair ability.

Microplastics and nanoplastics (MNPs) are emerging environmental contaminants that have received significant attention in recent years. Currently, there are more studies on the toxic effects of MNPs exposure on animals (especially aquatic organisms and mammals), but data on the reduction of toxic effects caused by MNPs exposure are still very limited. Lactic acid bacteria (LAB), recognized as safe food-grade microorganisms, possess the capability to bioconjugate harmful substances. In this experiment, we chose lactic acid bacteria (LAB) with different binding capacities to MNPs in vitro to intervene in MNPs-exposed mice to investigate the reducing effect on the toxicity caused by MNPs exposure. Our study showed that LAB with a high intercalation capacity with MNPs in vitro were more effective in alleviating the toxicity caused by MNPs exposure. Notably, Lactobacillus plantarum DT22, despite its low inter-adsorption with MNPs, played a pivotal role in upregulating the relative expression of tight junction proteins and modulating the intestinal microbiota. Thus, LAB strains' mitigation of MNPs toxicity extends beyond bio-binding; their capacity to repair the damaged gut environment is also crucial. LAB strains are proposed as a dietary intervention to reduce MNPs-induced toxicity.