Multi-dimensional visualization of ingestion, biological effects and interactions of microplastics and a representative POP in edible jellyfish

The FOXO pathway mediates a conserved mechanism of antioxidant defense against microplastic-induced toxicity in Aurelia coerulea polyps and mouse liver

Microplastics are emerging as a critical class of pollutants with a pervasive presence in the atmosphere, oceans, and terrestrial environments, raising global concern. However, it is unclear whether there are conserved mechanisms for the response of microplastic damage to different species. Aurelia coerulea polyps and mouse models were exposed to microplastic environments to assess their growth effects and mechanisms. The similarities and differences in the defence mechanisms of the two species after exposure to microplastics were analysed by means of phenotypic observations, transcriptome sequencing, pathological sections, oxidative stress indicators, explosions and molecular docking. Exposure to 200 mg/L of PS-MPs resulted in morphological changes, tissue damage, and oxidative stress in polyps. Exposure to 600 mg/L of PS-MPs led to increased toxicity in the mouse liver, including rupture and apoptosis of mitochondria and nuclei in hepatocytes, as well as oxidative stress. Meanwhile, we found that their antioxidant defense and DNA damage repair pathways were significantly altered. In addition, we found that the same loci existed in the foxo pathway in both species, and the enriched gene sequences were 48.33 % similar. Molecular docking showed conserved regions between polyps NLK and mouse Mapk13, indicating similar kinase activities, but overall structural and functional differences suggest species-specific. This finding provide new insights into understanding the mechanisms of toxicity of MPs to different organisms.

Effects of combined exposure to polystyrene microplastics and 17α-Methyltestosterone on the reproductive system of zebrafish

Polystyrene microplastics (PS-MPs) are important carriers of pollutants in water. 17α-Methyltestosterone (MT) is a synthetic environmental endocrine disrupting chemical (EDC) with androgenic effects. To study the effects of PS-MPs and MT on zebrafish reproductive systems, zebrafish were exposed to 0 or 50 ng L-1 MT, 0.5 mg∙L-1 PS-MPs, or 50 ng∙L-1 MT + 0.5 mg∙L-1 PS-MPs for 21 d. The results showed that the different exposure reagents caused varying degrees of damage to the reproductive systems in zebrafish, with the extent of damage increasing as the exposure duration increased. Histological analysis of the gonads revealed that the ratio of mature oocytes and mature spermatozoa in the gonad decreased gradually with increased exposure time, with the ratio being Control > PS-MPs > MT > MT + PS-MPs in decreasing order. The results of quantitative real-time PCR (qRT‒PCR) showed that in female fish treated for 7 d, the expression of cyp11a mRNA was significantly reduced in all three treatment groups(MT, PS-MPs, and MT + PS-MPs), while in the group treated for 14 d with MT + PS-MPs, the expression of cyp19a1a and StAR mRNA was significantly increased. In male fish exposed for 21 d, the expression of cyp11a, cyp17a1, cyp19a1a, StAR, 3β-HSD, and 17β-HSD3 mRNA was significantly decreased in MT + PS-MPs. ELISA results showed that after 14 d of exposure, the levels of E2, LH, and FSH in the ovaries of female fish were significantly reduced in all three treatment groups. Similarly, the levels of T, E2, LH, and FSH in the testis of male fish were significantly reduced after 14 d of exposure to PS-MPs and MT + PS-MPs. Offspring of zebrafish exposed to MT and MT + PS-MPs exhibited delayed incubation time and slow development. The cross-generational toxicity of PS-MPs themselves may be negligible, but it can exacerbate the toxicity of MT, making the cross-generational effects more pronounced in the offspring, causing offspring mortality and malformations. Offspring of zebrafish exposed to MT and MT + PS-MPs exhibited delayed incubation time and slow development. In addition, MT caused malformations such as pericardial edema, yolk cysts, and spinal deformities in zebrafish during the incubation period.