Polyvinyl chloride microplastics induce growth inhibition and oxidative stress in Cyprinus carpio var. larvae

Abstract The occurrence and accumulation of microplastics waste have become a growing global concern over the past decade. To evaluate the potential toxic effects of PVC (polyvinyl chloride) microplastics in freshwater larvae fish, we conducted chronic 30-day and 60-day dietary exposure using larvae fish of Cyprinus carpio var. We exposed fish to four treatments with different concentrations (food ration in diets): a no-plastic (i.e. control), 10%, 20% and 30%-microplastics treatment. The results indicated that microplastics significantly inhibited the weight gain and body length growth in all treatments of PVC exposure compared to control group. SOD (superoxide dismutase) and CAT (catalase) activities were analyzed and an inverse relationship between them was observed. The activities of GPx (glutathione peroxidase) appeared in the trend of first ascending then descending with the increase of PVC concentration after 30-day exposure. And it displayed downtrend with dose dependence after 60 days of exposure. MDA (malondialdehyde) level were significantly reduced upon exposure to different concentrations of microplastics in various tissues. Altered antioxidant-related gene expression was observed in the liver of fish exposed to the PVC microplastics. CYP1A and GSTa transcription initially grew and then reduced with the increasing concentration after 30-day exposure. In addition, histological observation revealed cytoplasmic vacuolation, inflammatory cell infiltration, and nuclear disappearance in the liver by 20%PVC and 30%PVC microplastics exposure.