Cadmium (Cd) is a heavy metal that accumulates easily in organisms and causes several detrimental effects, including tissue damage. Cd contamination from anthropogenic terrestrial sources flows into rivers, and through estuaries to the ocean. To evaluate the toxic effects of Cd on estuary crustaceans, we exposed the mud crab Scylla paramamosain to various Cd concentrations (0, 10.0, 20.0, and 40.0 mg/L) for 24 h. We also exposed mud crabs to a fixed Cd concentration (20.0 mg/L) for various periods of time (0, 6, 12, 24, 48, and 72 h). We observed that after exposure to Cd, the surfaces of the gill lamellae were wrinkled, and the morphologies of the nuclei and mitochondria in the hepatopancreas were altered. We analyzed the expression profiles of 36 stress-related genes after Cd exposure, including those encoding metallothioneins, heat shock proteins, apoptosis-related proteins, and antioxidant proteins, with quantitative reverse transcription PCR. We found that exposure to Cd altered gene expression, and that some genes might be suitable bioindicators of Cd stress. Gene expression profiles were organ-, duration-, and concentration-dependent, suggesting that stress-response genes might be involved in an innate defense system for handling heavy metal exposure. To the best of our knowledge, this study is the first one of histopathology and stress-response gene expression pattern of Scylla paramamosain after Cd exposure. Our work could increase our understanding of the effect of environmental toxins on estuary crustaceans.

镉（Cd）是一种重金属，很容易在生物体中累积，并造成多种有害作用，包括组织损伤。人为陆地来源的镉污染流入河流，并通过河口流入海洋。为了评估镉对河口甲壳类动物的毒性作用，我们暴露了泥蟹Scylla paramamosain达到24小时内各种Cd浓度（0、10.0、20.0和40.0 mg / L）的浓度。我们还在不同的时间段（0、6、12、24、48和72小时）将泥蟹暴露于固定的Cd浓度（20.0 mg / L）。我们观察到，暴露于Cd后，g薄片的表面起皱，并且肝胰脏中核和线粒体的形态发生了变化。我们使用定量逆转录PCR分析了镉暴露后36种与压力相关的基因的表达谱，包括编码金属硫蛋白，热休克蛋白，凋亡相关蛋白和抗氧化剂的那些基因。我们发现暴露于Cd会改变基因表达，并且某些基因可能是Cd胁迫的合适生物指标。基因表达谱是器官，持续时间和浓度依赖性的，这表明应激反应基因可能参与了处理重金属暴露的先天防御系统。据我们所知，本研究是第一个组织病理学和应激反应基因表达模式的研究。镉暴露后的Sylla paramamosain。我们的工作可能会加深我们对环境毒素对河口甲壳类动物影响的理解。