Combined negative effects of microplastics and plasticizer DEHP: The increased release of Nets delays wound healing in mice

Environmental harmful pollutants microplastics (MPs) and di (2-ethyl) hexyl phthalate (DEHP) are widely residual in the environment, which may cause lesion to multiple apparatus by inducing oxidative stress, threatening the health of human and animals. Neutrophil extracellular traps (Nets) are involved in skin wound healing. Most studies focused on the individual effects of different poisons on animals and ecosystems, but there are few studies on the accumulation and interaction of multiple poisons. The purpose of this study is to explore the effect of DEHP and MPs co-exposure on skin wound healing and the formation of Nets. For this purpose, we detected this hypothesis by replicating the DEHP and MPs-exposed skin wound model in mice, as well as the co-culture system of neutrophil and fibroblast. The results displayed that MPs and DEHP exposure delayed skin healing, which was more pronounced in the combined exposure group. In vitro and in vivo experiments confirmed that compared with the DEHP or MPs group, the DEHP+MPs group had more significant oxidative stress, increased Nets release and inflammatory factors, and inhibited the Wnt/β-catenin pathway and fibrosis-related factors. N-acetylcysteine (NAC) attenuated these phenomena. Through the co-culture system, we confirmed that the overproduction of Nets induced fibroblasts to exacerbate inflammatory responses and inhibit Wnt pathway and fibrosis. Overall, DEHP and MPs can produce synergistic toxic injury in mice skin wounds, and the excessive activation of ROS/Nets can aggravate inflammatory and inhibit fibrosis, resulting in delayed wound healing.