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Updated: Jun 30, 2025
Accumulation and Distribution of Fluorescent Microplastics in the Early Life Stages of Zebrafish
Published on: July 4, 2021
Microcystin-LR and polystyrene microplastics jointly lead to hepatic histopathological damage and antioxidant
1College of Life and Environmental Sciences, Hunan University of Arts and Science, Changde, 415000, PR China; Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming, 650500, PR China; Hunan Provincial Key Laboratory for Molecular Immunity Technology of Aquatic Animal Diseases, Changde, 415000, PR China.
Abstract:
The co-occurrence of cyanobacterial blooms and nano-microplastic pollution in the water is becoming an emerging risk. To assess the combined hepatotoxicity of microcystin-LR (MC-LR) and polystyrene microplastics (PSMPs) on zebrafish (Danio rerio), male adult zebrafish were exposed to single MC-LR (0, 1, 5, 25 μg/L) and a mixture of MC-LR and PSMPs (100 μg/L). After 60 d exposure, the results indicated that PSMPs significantly increased the MC-LR bioaccumulation in the livers in contrast to the single 25 μg/L MC-LR treatment group. Moreover, the severity of hepatic pathological lesions was aggravated in the MC-LR + PSMPs treatment groups, which were mainly characterized by cellular vacuolar degeneration, swollen hepatocytes, and pyknotic nucleus. The ultrastructural changes also proved that PSMPs combined with MC-LR could enhance the swollen mitochondria and dilated endoplasmic reticulum. The biochemical results, including increased malondialdehyde (MDA) and decreased glutathione (GSH), indicated that PSMPs intensified the MC-LR-induced oxidative damage in the combined treatment groups. Concurrently, alterations of sod1 and keap1a mRNA levels also confirmed that PSMPs together with MC-LR jointly lead to enhanced oxidative injury. Our findings demonstrated that PSMPs enhanced the MC-LR bioavailability by acting as a vector and exacerbating the hepatic injuries and antioxidant dysfunction in zebrafish.
