POPULATION-DEPENDENT STRESS RESPONSE OF BIVALVE MOLLUSC UNIO TUMIDUS TO IBUPROFEN, MICROPLASTIC AND THEIR MIXTURE

Non-steroidal anti-inflammatory drugs are among the most distributed pharmaceuticals in the surface waters. Microplastics (MPs) in the water column can modulate the effects of drugs, particularly in the filter feeders. This study aimed to indicate the effect of ibuprofen (IBU) and MP on the bivalve molluscs at environmentally relevant sub-chronic exposures utilizing biomarkers of stress and toxicity. The specimens of Unio tumidus from pristine (Pr) and contaminated (Ct) areas were treated with IBU (0.8 µg L−1), MP (1 mg L−1, size 0.1–0.5 mm), or their combination (Mix) for 14 days. Untreated mussels served as controls for pristine and contaminated areas, respectively Pr(C)- and Ct(C)-group. The Pr(C)-group had higher levels of antioxidants Mn-SOD, Cu, Zn-SOD, and catalase as well as lesser levels of oxidative lesions (TBARS and protein carbonyls) and cholinesterase (ChE) than the Ct(C)-group. The only similar response to MP in both populations was the activation of Mn-SOD. Generally, stress responses were dependent on the site rather than on the exposure: Ct-groups showed enhanced stress, whereas Pr-groups were characterized by fairly stable levels of oxidative stress indexes in all the treatments. The action of IBU and Mix increased the ChE activity in both populations and lysosomal integrity in Ct-groups. The integrated biochemical and discriminant analyses indicated the modulation of IBU-induced responses by MP in both populations, particularly in the molluscs from the contaminated area.

非甾体抗炎药是地表水中分布最为广泛的药物之一。水体中的微塑料（MPs）能够调节药物的作用，尤其是在滤食性生物中。本研究旨在通过利用压力和毒性的生物标志物，在环境相关的亚慢性暴露下，探究布洛芬（IBU）和微塑料对双壳软体动物的影响。来自原生（Pr）和污染（Ct）区域的Unio tumidus标本分别被处理以IBU（0.8 µg L−1）、MP（1 mg L−1，尺寸为0.1–0.5 mm）或其组合（Mix）14天。未经处理的贻贝分别作为原生和污染区域的控制组，即Pr(C)-组和Ct(C)-组。与Ct(C)-组相比，Pr(C)-组的抗氧化剂Mn-SOD、Cu、Zn-SOD和过氧化氢酶水平更高，而氧化损伤（TBARS和蛋白质羰基）和胆碱酯酶（ChE）水平更低。两个种群中，对MP的唯一相似反应是Mn-SOD的激活。总体而言，压力反应取决于地点而非暴露：Ct组表现出增强的压力反应，而Pr组在所有处理中均以相对稳定的氧化应激指标水平为特征。IBU和Mix的处理增加了两个种群中的ChE活性和Ct组中的溶酶体完整性。综合生物化学和判别分析表明，MP调节了IBU诱导的反应，尤其是在污染区域的软体动物中。