Department of Ecology/Hydrobiology Research Institute, Jinan University, Guangzhou 510632, China.
Department of Ecology/Hydrobiology Research Institute, Jinan University, Guangzhou 510632, China; Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, China.
Ecotoxicol Environ Saf. 2018 Jun 15;154:228-236. doi: 10.1016/j.ecoenv.2018.02.015. Epub 2018 Feb 22.
As a widely used lipid lowering agent, simvastatin recently has been frequently detected in aquatic environment and the potential adverse effects from simvastatin exposure to non-target organisms such as fish is worthy of more attention. The aim of this study was to reveal the responses of detoxification system in fish to simvastatin exposure. In this investigation a ubiquitous small freshwater fish, mosquito fish (Gambusia affinis), was employed as test organism, and the transcriptional expression of nucleus transcriptional factor pregnane X receptor (PXR) and its downstream genes, including P-glycoprotein (P-gp), cytochrome 3A (CYP3A), multidrug resistance protein 2 (MRP2), UDP-glucuronosyl transferase (UGT) in mosquito fish were investigated by qRT-PCR methods under the exposure of concentrations of simvastatin (0.5 μg L, 5 μg L, 50 μgL, 500 μg L) for 24 h, 72 h and 168 h. The related enzyme activity (Erythromycin-N-Demethylase, ERND), the protein expression of PXR and the histological changes of liver tissues in fish were also determined via west blotting and transmission electron microscope approaches in the same conditions. Results showed that the mRNA expression of PXR, CYP3A and P-gp showed significantly changes under simvastatin exposure, exhibiting an obvious time/dose-effect relationship with the prolong of exposure time. ERND activity also showed time-effect at 24 h, and western blotting showed PXR protein displaying a dose-effect relationship to some extent. Hepatocyte cellular of mosquito fish exposed to simvastatin (5 μg L, 168 h) exhibited obvious histological changes in form of swelling, incomplete fragmentary structure etc. Overall, simvastatin altered the expression of PXR signaling pathway and subsequently bring about changes in high-levels of mosquito fish.
作为一种广泛使用的降脂药物，辛伐他汀最近经常在水生环境中被检测到，辛伐他汀暴露对鱼类等非靶标生物的潜在不利影响值得更多关注。本研究旨在揭示鱼类解毒系统对辛伐他汀暴露的反应。在这项研究中，我们选择了一种普遍存在的小型淡水鱼类——食蚊鱼（Gambusia affinis）作为试验生物，采用 qRT-PCR 方法研究了辛伐他汀（0.5μg/L、5μg/L、50μg/L、500μg/L）暴露 24h、72h 和 168h 后，食蚊鱼细胞核转录因子孕烷 X 受体（PXR）及其下游基因，包括 P-糖蛋白（P-gp）、细胞色素 3A（CYP3A）、多药耐药蛋白 2（MRP2）、UDP-葡萄糖醛酸转移酶（UGT）的转录表达，并在相同条件下通过 Western blot 和透射电镜方法测定了相关酶活性（红霉素-N-去甲基酶，ERND）、PXR 蛋白表达和鱼肝脏组织的组织学变化。结果表明，PXR、CYP3A 和 P-gp 的 mRNA 表达在辛伐他汀暴露下发生显著变化，表现出明显的时间/剂量效应关系，随着暴露时间的延长而增加。ERND 活性在 24h 时也表现出时间效应，Western blot 显示 PXR 蛋白在一定程度上呈现剂量效应关系。暴露于辛伐他汀（5μg/L，168h）的食蚊鱼肝细胞呈现出肿胀、结构不完整等明显的组织学变化。总之，辛伐他汀改变了 PXR 信号通路的表达，进而导致食蚊鱼的高水平变化。
