Heavy metal contamination severely affects the aquatic environment and organisms. Copper (Cu) and cadmium (Cd) are two of the most common heavy metal contaminants that impair the survival, development, and reproduction of aquatic organisms. With the growth of agriculture and industry, there is a possibility of heavy metal pollution in Coregonus ussuriensis Berg’s water source. However, there are no published studies on the toxicity to C. ussuriensis. Acute toxicity experiments in C. ussuriensis revealed the 96-h median lethal concentrations of copper and cadmium to be 0.492 mg·L⁻¹ (95% confidence interval: 0.452–0.529) and 1.548 mg·L⁻¹ (95% confidence interval: 1.434–1.657), respectively, and safe concentrations of 4.92 µg·L⁻¹ and 15.48 µg·L⁻¹, respectively. C. ussuriensis was then treated for 96 h with Cu (20% of 96 h LC₅₀), Cd (20% of 96 h LC₅₀), and a combination of Cu and Cd (20% of Cu 96 h LC₅₀ + 20% of Cd 96 h LC₅₀). The histological damage caused by the three different exposure modes to the liver and gills of C. ussuriensis was verified using hematoxylin and eosin staining. All three exposure modes caused different degrees of vacuolization, nuclear consolidation, and necrosis in the liver tissue of C. ussuriensis and edema, hyperplasia, laminar fusion, and epithelial elevation in the gill tissue compared with the reference group. The severity of the damage increased with increasing exposure time. Anti-oxidant activity in the gill and liver tissues were measured using enzyme activity assay kits to reflect oxidative stress induced by copper and cadmium exposure alone and in combination. The enzyme activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH) were substantially higher than those in the reference groups. However, the activities of the enzymes decreased with increasing exposure time. Malondialdehyde (MDA) activity significantly increased during exposure in relation to that in the reference group. Analysis of immune gene expression in C. ussuriensis gill and liver tissues was executed using real-time inverse transcript polymerase chain response (RT-PCR). The expression levels of the pro-inflammatory cytokines interleukin one beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) were positively correlated with exposure time and were significantly upregulated with increasing exposure time. Metallothionein (MT) gene expression levels were significantly upregulated in the short term after exposure compared to the reference group but decreased with increasing exposure time. Our results indicate that exposure to aqueous copper and cadmium solutions, either alone or in combination, causes histopathological damage, oxidative stress, and immunotoxicity in C. ussuriensis gill and liver tissue. This study investigated the toxic effects of copper and cadmium on C. ussuriensis to facilitate the monitoring of heavy metals in water sources for healthy aquaculture.

重金属污染严重影响水生环境和生物。铜 (Cu) 和镉 (Cd) 是两种最常见的重金属污染物，会损害水生生物的生存、发育和繁殖。随着农业和工业的发展，乌苏里金龟的水源存在重金属污染的可能性。然而，尚未发表关于乌苏里念珠菌毒性​​的研究。乌苏里念珠菌急性毒性实验显示，铜和镉的96小时中位致死浓度分别为0.492 mg·L ^-1 (95%置信区间：0.452–0.529)和1.548 mg·L ^-1 (95%置信区间： 1.434–1.657），安全浓度分别为4.92 µg·L ^-1和15.48 µg·L ^-1。然后用 Cu（96 h LC ₅₀的 20% ）、Cd（96 h LC ₅₀的 20% ）以及 Cu 和 Cd 的组合（Cu 96 h LC ₅₀  + 20的 20%）处理乌苏里 C. ussuriensis 96 小时。 % Cd 96 h LC ₅₀ )。使用苏木精和伊红染色验证了三种不同暴露模式对乌苏里线虫肝脏和鳃造成的组织学损伤。与参照组相比， 3种暴露模式均导致乌苏里红线虫肝组织出现不同程度的空泡化、核实变、坏死，鳃组织出现不同程度的水肿、增生、层状融合、上皮隆起。损害的严重程度随着暴露时间的增加而增加。使用酶活性测定试剂盒测量鳃和肝组织中的抗氧化活性，以反映铜和镉单独和组合暴露引起的氧化应激。超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和谷胱甘肽过氧化物酶（GSH）的酶活性显着高于参考组。然而，酶的活性随着暴露时间的增加而降低。与参考组相比，暴露期间丙二醛（MDA）活性显着增加。使用实时逆转录聚合酶链反应（RT-PCR）对乌苏里乌苏里鱼鳃和肝组织中的免疫基因表达进行分析。促炎细胞因子白介素一β（IL-1β）和肿瘤坏死因子-α（TNF-α）的表达水平与暴露时间呈正相关，并且随着暴露时间的增加而显着上调。金属硫蛋白（MT）与参考组相比，暴露后短期内基因表达水平显着上调，但随着暴露时间的增加而下降。我们的结果表明，单独或组合暴露于铜和镉水溶液中，会导致乌苏里梭菌鳃和肝组织的组织病理学损伤、氧化应激和免疫毒性。本研究调查了铜和镉对乌苏里铜藻的毒性作用，以促进健康水产养殖中水源中重金属的监测。