The effect of polyethylene terephthalate and abamectin on oxidative damages and expression of vtg and cyp1a genes in juvenile zebrafish

Abstract

Increasing the abundance and wide distribution of microplastics is one of the most important concerns of biological communities. These particles can act as carriers of environmental chemical pollutants and pesticides. Absorption of these particles by living organisms, especially aquatic organisms, may cause changes in the gene expression as well as enzymes activity in the antioxidant pathway. In this study, combined and individual effects of polyethylene terephthalate (PET) microplastics, as one of the most widely used plastics in industry, and abamectin (ABM) pesticide was evaluated on glutathione content, total antioxidant capacity, free radical scavenging, vitellogenin (vtg) and cytochrome P450, family 1, subfamily a (cyp1a) gene expression in zebrafish. The results indicated that microplastics (MPs) in combination with pesticides reduced the content of glutathione. The gene expression of cyp1a showed significant decreased in zebrafish after treatment with ABM alone and in combination with microplastic, while the expression of vtg gene was significantly increased in samples treated with combination of ABM and MPs. Analysis of antioxidant activity revealed that glutathione content, glutathione peroxidase and DPPH activity were not affected by MPs when applied alone, but it increased the total antioxidant capacity and also inhibited the superoxide dismutase (SOD) activity. ABM had no effect on glutathione peroxidase and DPPH activity, but it reduced SOD activity. Also, the combination of microplastic and toxin increased glutathione peroxidase activity and decreased the glutathione content, SOD and DPPH activity. In general, the result of this study demonstrated that the effect of MPs cannot be ignored in increasing the toxicity of other pollutants.