Effect of polystyrene microplastics on apoptosis of male germ cells

To investigate the effect of polystyrene microplastic（PS-MPs）on the apoptosis of male germ cells.

Genes related to male urogenital disorders caused by polystyrene were searched in the Comparative Toxicogenomics Database（CTD）. Gene Ontology（GO）analysis and Kyoto Encyclopedia of Genes and Genomes（KEGG）analysis were used to analyze the involved functions and signaling pathways. A cell model was established based on mouse mesenchymal cells（TM3 cells）, and then 0, 10, 20 and 40 μg/mL PS-MPs with a particle size of 5 μm and 80 nm respectively were used to treat TM3 cells respectively for 48 h. Cell morphology was observed, cell viability was detected with CCK-8 assay, apoptosis by flow cytometry, and mRNA and protein expression levels of key molecules in the p53 signaling pathway were detected by RT-qPCR and Western blotting, respectively.

GO and KEGG enrichment analyses showed that the genes screened from CTD database were found to be significantly enriched in cell apoptosis and p53 signaling pathway（P<0.05）. PS-MPs of 5 μm and 80 nm in size treatment for 48 h resulted in significant inhibition of cell growth while enhancement in cell apoptosis（P<0.05）, up-regulated the mRNA and protein levels of p53 and Bax in the p53 signaling pathway（P<0.05）, enhanced downstream molecules Caspase3 and Caspase9（P<0.05）, and inhibited Bcl2 at mRNA and protein levels in TM3 cells（P<0.05）.

PS-MPs exposure may induce apoptosis of testicular mesenchymal TM3 cells via the p53 signaling pathway.