This study explores the intestinal toxicity of combined copper sulfate (Cu) and polystyrene microplastics (PS) exposure in male mice. Histopathological examination, intestinal barrier function assessment, 16S rRNA sequencing, and transcriptome analysis were performed to explore the underlying mechanisms. The results showed that combined exposure significantly decreased ileal villus height, aggravated tissue damage, and evidently suppressed the synthesis of tight junction structural proteins, including claudin, ZO-1, and occludin. Analysis of 16S rRNA sequencing indicated that combined exposure markedly altered intestinal microbial structure, leading to a reduction of beneficial bacteria, enrichment of inflammation-related bacteria, and significant intestinal flora remodeling. Transcriptome profiling identified a total of 4026 differentially expressed genes (DEGs) in the co-exposure group, with 3226 specific DEGs, which was significantly higher than that in the single exposure groups. Functional enrichment analyses based on GO and KEGG databases demonstrated that DEGs were mainly involved in inflammation-associated signaling pathways. Among these were antigen presentation, IgA immune network, development and differentiation of T cells, and NOD-like receptor signaling axis. In conclusion, combined exposure to Cu and PS exerts obvious combined effects on intestinal flora disturbance and intestinal barrier damage in mice.

To Cite This Article: Lv B, Zhang H, Zhang Z, Pan Y, Kang S, Chen M, Li X, Ataya FS, Luo R, and Chang Z, 2026. Combined exposure to copper sulfate and polystyrene microplastics alters intestinal microbiota structure and induces barrier damage in male mice. Pak Vet J, 46(5): 1264-1275. http://dx.doi.org/10.29261/pakvetj/2026.113