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广泛的药物之一。水体中的微塑料（Microplastics, MPs）可调控药物的生态效应，尤其对滤食性生物影响显著。本研究借助应激与毒性生物标志物，旨在探究环境相关浓度的亚慢性暴露条件下，布洛芬（ibuprofen, IBU）与微塑料对双壳类软体动物的作用效果。 实验选取采自未受污染（Pr）区域与受污染（Ct）区域的圆顶珠蚌（Unio tumidus）样本，分别以0.8 μg·L⁻¹布洛芬、1 mg·L⁻¹粒径0.1–0.5 mm的微塑料，以及二者的混合体系（Mix）处理14天。未处理的圆顶珠蚌分别作为未受污染区域对照组（Pr(C)-组）与受污染区域对照组（Ct(C)-组）。 相较于Ct(C)-组，Pr(C)-组的抗氧化酶Mn-SOD、Cu,Zn-SOD及过氧化氢酶水平更高，而氧化损伤标志物（硫代巴比妥酸反应物TBARS与蛋白质羰基）及胆碱酯酶（ChE）水平更低。仅在Mn-SOD的激活这一响应上，两个种群对微塑料的反应一致。 总体而言，应激响应主要取决于采样位点而非暴露处理：受污染组的应激水平显著升高，而未受污染组在所有处理下的氧化应激指标均维持在相对稳定的水平。 布洛芬与混合体系处理均可提升两个种群的胆碱酯酶活性，同时提升受污染组的溶酶体完整性。 整合生化分析与判别分析结果显示，微塑料可调控布洛芬诱导的种群响应，这一效应在采自受污染区域的软体动物中尤为突出。