Subchronic Exposure to Polystyrene Microplastic Differently Affects Redox Balance in the Anterior and Posterior Intestine of Sparus aurata

Abstract

Microplastics (MPs) are pollutants widely distributed in aquatic ecosystems. MPs are introduced mainly by ingestion acting locally or in organs far from the gastroenteric tract. MPs-induced health consequences for fish species still need to be fully understood. We aimed to investigate the effects of the subchronic oral exposure to polystyrene microplastics (PS-MPs) (1–20 μm) in the gilthead seabreams (Sparus aurata) used as the experimental model. We studied the detrimental impact of PS-MPs (25 and 250 mg/kg b.w./day) on the redox balance and antioxidant status in the intestine using histological analysis and molecular techniques. The research goal was to examine the anterior (AI) and posterior intestine (PI) tracts, characterized by morphological and functional differences. PS-MPs caused an increase of reactive oxygen species and nitrosylated proteins in both tracts, as well as augmented malondialdehyde production in the PI. PS-MPs also differently affected gene expression of antioxidant enzymes (i.e., superoxide dismutase, catalase, glutathione reductase). Moreover, an increased up-regulation of protective heat shock proteins (HSPs) (i.e., hsp70 and hsp90) was observed in PI. Our findings demonstrate that PS-MPs are responsible for oxidative/nitrosative stress and alterations of detoxifying defense system responses with differences in AI and PI of gilthead seabreams.

Effects of polystyrene nanoplastics on apoptosis, digestive enzymes, and intestinal histological structure and flora of swamp eel (Monopterus albus)

“…This suggests that, at a high PS-NP concentration, the internal reaction mechanism of Hsp70 was activated and further induced other immune factors to participate in immune defense, results of which are consistent with those reported in other aquatic animals exposed to PS-NPs. [61][62][63] Hsp70 can also have a role in the release of proinflammatory cytokines, cell proliferation, cell migration, 64,65 and other functions by interacting with receptors on the surface of immune cells and regulating key inflammatory regulatory factors, such as TNF-α and IL-1β. 66,67 TNF-α and IL-1β are important proinflammatory factors in the inflammatory response in fish and cause vasodilation and increased vascular permeability.…”

Microplastics in aquaculture - Potential impacts on inflammatory processes in Nile tilapia

“…The expression of IL-1β was upregulated in both proximal and distal intestines [ 52 ]. The same group previously found these differences in proximal and distal intestinal tissue along with effects in the histology of the intestines, as a reduced villi height, reduced number of goblet cells, and elevated signs of oxidative stress by ingestion of polystyrene microplastics in seabream [ 67 ].…”