Danio rerio as a Model Animal for Assessing Microplastic Toxicity

Microplastics are presently a major worldwide hazard, whether they come from massive plastic breakdown or directly from consumer and industrial items. By altering their physicochemical characteristics, weathering processes of plastics cause the fragmentation of polymers into microplastics. Due to delayed disposal of plastic waste, a lack of detecting equipment and specific removal techniques and a slow disposal rate, microplastics are prevalent in the environment. Microplastics are tiny enough to be easily absorbed. As a result, the presence of microplastics poses a hazard to both live species present in benthic zones and the water column. Microplastics therefore have non-lethal impacts on these creatures. In the present paper, various studies have been reviewed to find the effects of microplastics on Danio rerio (Zebrafish). Various microplastics caused epithelial damage, lipid accumulation in the liver, metabolic changes, adverse effects on gonads, obstructed fin regeneration and contraction parameters in the heart tissue of Danio rerio. Exposure to polystyrene decreased the bioavailability and bioaccumulation of F-53B which significantly reduced the body weight of Danio rerio larvae and resulted in oxidative stress and inflammation. Other sublethal effects included significant decrease in swimming distance as well as speed. Acetylcholinesterase activity of Danio rerio was remarkably inhibited by the microplastic exposure which further induced the immune responses. These findings emphasise the health hazards associated with microplastic pollution in aquatic ecosystems. Further studies are needed to assess the health impacts associated with microplastic exposure and their possible remedies.