塑料垃圾在水生环境中的堆积对环境构成了严重威胁,野生动物,最终是人类。具体来说,水生动物摄入微塑料(MPs)会导致不利的生理和毒理学影响。此外,废弃的MPs经历老化和降解过程,影响其形态特性和化学成分,增强对环境污染物的吸收。在这个棱镜下,本研究旨在调查和比较“老化”与原始低密度聚乙烯微塑料(PE-MPs)对各种毒性终点的影响,这些终点是淡水鱼种Percafluviatilis的肌肉组织和肝脏中的生化和分子参数。并行,形态学,物理化学,和结构变化发生在“老年”PE-MP中,(暴露于紫外线辐射120天后)进行了研究,显着说明氧化和裂纹扩展的迹象在所研究的MPs的表面。鱼暴露于含有处女和“老年”PE-MP的人工饮食中,尺寸为100-180μm,浓度为1mg/g干食物,持续15天。此后,分析肝脏和肌肉组织与多种氧化参数的关系。与对照组相比,在被检查的鱼中观察到的变化包括抗氧化酶的活性增加,作为超氧化物歧化酶,过氧化氢酶和谷胱甘肽还原酶,丙二醛的浓度增加,蛋白质羰基化,HSP70水平,升高的MAPK磷酸化,泛素蛋白的诱导,以及Bax/Bcl-2蛋白水平升高,胱天蛋白酶和LC3II/I的分化水平,SQSTM1/p62。从研究的生物标志物中,凋亡,泛素和hsp70水平,对摄入的议员表现出更敏感的反应,其次是自噬,p38MAPK级别,抗氧化酶,MDA和羰基化水平。与处女相比,“老年”PE-MP的作用更为明显。在评估研究组织中所有氧化应激生物标志物的反应时,对于大多数生物标志物,肝脏对处女和“老年”PE-MPs的反应最高。这些发现强烈表明,“老化的”MPs激活了抗氧化剂防御机制,并影响了所检查鱼类的细胞健康。
The buildup of plastic waste in aquatic environments presents serious threats to the environment, wildlife, and ultimately to humans. Specifically, microplastics (MPs) ingestion by aquatic animals leads to adverse physiological and toxicological effects. In addition, discarded MPs undergo aging and degradation processes which affect their morphological properties and chemical composition, enhancing the absorption of environmental pollutants. Under this prism, the present research was conducted to investigate and compare the impact of \'aged\' versus pristine low-density polyethylene microplastics (PE-MPs) on various toxicity endpoints as biochemical and molecular parameters in the muscle tissue and liver of the freshwater fish species Perca fluviatilis. In parallel, the morphological, physicochemical, and structural changes occurred in \"aged\" PE-MPs, (after being exposed to UV radiation for 120 days) were studied, significantly illustrating signs of oxidation and crack propagation at the surface of the studied MPs. Fish were exposed to artificial diet reached with virgin and \"aged\" PE-MPs, sized 100-180 μm, at concentrations of 1 mg/g of dry food for a period of 15-days. Thereafter, liver and muscle tissues were analyzed in relation to multi oxidative parameters. Compared to the control group, the observed changes in the examined fish included increased activities of antioxidant enzymes, as superoxide dismutase, catalase and glutathione reductase, enhanced concentrations of malondialdehyde, protein carbonylation, HSP70 levels, elevated MAPK phosphorylation, induction of ubiquitin-proteins, as well as heightened levels of Bax/Bcl-2 proteins, caspases and differentiated levels of LC3 II/I, SQSTM1/p62. From the studied biomarkers, apoptosis, ubiquitin and hsp70 levels, showed a more sensitive response against the ingested MPs, followed by autophagy, p38MAPK levels, antioxidant enzymes, MDA and carbonylation levels. The effect of \"aged\" PE-MPs was more pronounced compared to that of the virgin ones. When evaluating the response of all oxidative stress biomarkers across the studied tissues, the liver demonstrates the highest response for the majority of the biomarkers against both virgin and \"aged\" PE-MPs. These findings strongly indicate that \"aged\" MPs activate the antioxidant defence mechanisms and impact the cellular well-being of the examined fish species.