College of Ocean and Earth Sciences, Xiamen University, Xiamen, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China.
Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China.
Aquat Toxicol. 2019 Aug;213:105220. doi: 10.1016/j.aquatox.2019.06.003. Epub 2019 Jun 3.
Tamoxifen (TAM) is an antiestrogenic agent and can enter the aquatic environment in wastewater. It has been reported that TAM can induce hepatic steatosis in vertebrates, however, the effects of TAM exposure on lipid metabolism of hepatopancreas in crustaceans remains unclear. In this study, four TAM concentrations (0, 6.7, 13.4 and 20 μg g crab body weight) were injected into the swimming-leg of swimming crabs Portunus trituberculatus, as a means of evaluating the effects of TAM on the expression levels of lipid metabolism-related genes, lipid composition, and hepatopancreas histology. The results showed that the mRNA levels of three lipogenic related genes (diacylglycerol acyltransferase 1 (DGAT1), acetyl-CoA carboxylase (ACC) and fatty acyl desaturase (FAD)) decreased significantly in the 6.7 μg g and 20 μg g TAM treatments compare to the control. The mRNA levels of fatty acid synthase (FAS) decreased significantly in a dose-dependent manner as TAM concentration increased. The mRNA levels of two lipid catabolism-related genes (acyl-CoA oxidase (ACOX) and fatty acid transport protein (FATP)) were down-regulated among the three TAM treatments, while the enzyme activity and mRNA level of carnitine palmitoyltransferase I (CPT-I) was up-regulated by TAM treatments. Compared to the control, the lowest levels of total lipids and phospholipids were detected in the 6.7 μg g TAM treatment, while the 20 μg g TAM treatment had the lowest free fatty acids concentration. The 6.7 μg g TAM treatment had the lowest percentages of 16:1n-7, 18:1n-9, 18:1n-7 and total monounsaturated fatty acids (∑MUFA), whilst simultaneously recording the highest percentages of 18:2n-6 and 20:2n-6 in this treatment. Moreover, histological observations indicated that TAM caused the walls of the hepatopancreatic tubules to become brittle, with a concurrent increase in the number of blister-like cells. These results suggest that TAM damages the hepatopancreas and leads to a reduction in hepatopancreatic lipid deposition in P. trituberculatus.
他莫昔芬（TAM）是一种抗雌激素药物，可进入废水的水生环境。据报道，TAM 可诱导脊椎动物肝脂肪变性，但 TAM 暴露对甲壳类动物肝胰腺脂质代谢的影响尚不清楚。在这项研究中，将四种 TAM 浓度（0、6.7、13.4 和 20μg/g 蟹体重）注入游泳蟹三疣梭子蟹的游泳腿中，以评估 TAM 对脂质代谢相关基因表达水平、脂质组成和肝胰腺组织学的影响。结果表明，与对照组相比，6.7μg/g 和 20μg/g TAM 处理组中三种生脂相关基因（二酰基甘油酰基转移酶 1（DGAT1）、乙酰辅酶 A 羧化酶（ACC）和脂肪酸去饱和酶（FAD））的 mRNA 水平显著降低。脂肪酸合酶（FAS）的 mRNA 水平随着 TAM 浓度的增加呈剂量依赖性降低。三种 TAM 处理组中两种脂质分解代谢相关基因（酰基辅酶 A 氧化酶（ACOX）和脂肪酸转运蛋白（FATP））的 mRNA 水平下调，而 TAM 处理组肉碱棕榈酰基转移酶 I（CPT-I）的酶活性和 mRNA 水平上调。与对照组相比，6.7μg/g TAM 处理组总脂质和磷脂含量最低，而 20μg/g TAM 处理组游离脂肪酸浓度最低。6.7μg/g TAM 处理组 16:1n-7、18:1n-9、18:1n-7 和总单不饱和脂肪酸（∑MUFA）的比例最低，同时该处理组中 18:2n-6 和 20:2n-6 的比例最高。此外，组织学观察表明，TAM 导致肝胰腺小管壁变脆，泡状细胞数量增加。这些结果表明，TAM 损害了肝胰腺，并导致 P. trituberculatus 肝胰腺脂质沉积减少。
