Environmental Toxicology Research Laboratory, NIH-RCMI Center for Environmental Health, College of Science, Engineering and Technology, Jackson State University, 1400 Lynch Street, Box 18750, Jackson, Mississippi, USA.
Environ Toxicol. 2011 Nov;26(6):649-56. doi: 10.1002/tox.20602. Epub 2010 May 20.
Hexavalent chromium [Cr (VI)] is a constituent of chromite ore. Although it is known to have several industrial and technological applications, its release into the aquatic environment as a result of chemical spill or inadequate waste discharge may hamper the health of aquatic organisms. In this study, we have investigated the effects of Cr (VI) on multiple biomarkers responses in goldfish under subchronic exposure conditions. Laboratory-acclimatized fish were exposed to 4.25 ppm and 8.57 ppm Cr (VI) for four weeks using a continuous flow-through system. During exposure, fish samples were collected on a weekly basis and analyzed for multiple biomarkers including catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), metallothionein (MT), and total protein in liver and kidney. Study results indicated that the CAT activity and total protein levels in Cr (VI) - treated goldfish did not significantly differ (P > 0.05) from their respective controls during experimentation. However, highly significant up-regulations (P < 0.05) of SOD, GPx, and MT expression in Cr (VI) - treated goldfish were recorded at different exposure times depending on Cr (VI) concentration, test organ, and/or biomarker of interest. For example, significantly higher liver GPx levels were found at weeks 2 and 3 in the 4.25 ppm concentration, and at weeks 3 and 4 in the 8.57 ppm, while kidney GPx levels were significantly higher at weeks 1, 2 and 3 in the 4.25 ppm concentration, and at weeks 2, 3 and 4 in the 8.57 ppm concentration. In summary, Cr (VI)-induced oxidative stress was characterized by statistically significant increases in SOD, GPx, and MT expression in goldfish tissues; with the kidney showing a relatively higher sensitivity to Cr (VI) toxicity compared with the liver.
六价铬[Cr（VI）]是铬铁矿的组成部分。尽管它具有多种工业和技术应用，但由于化学泄漏或废物排放不当而释放到水生环境中，可能会损害水生生物的健康。在这项研究中，我们研究了在亚慢性暴露条件下 Cr（VI）对金鱼的多种生物标志物反应的影响。使用连续流动系统，将实验室驯化的鱼暴露于 4.25 ppm 和 8.57 ppm Cr（VI）中四周。在暴露过程中，每周收集一次鱼样，并分析包括肝和肾中的过氧化氢酶（CAT）、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GPx）、金属硫蛋白（MT）和总蛋白在内的多种生物标志物。研究结果表明，在实验过程中，Cr（VI）处理的金鱼的 CAT 活性和总蛋白水平与各自的对照相比没有显着差异（P > 0.05）。然而，在不同的暴露时间，根据 Cr（VI）浓度、测试器官和/或感兴趣的生物标志物，Cr（VI）处理的金鱼的 SOD、GPx 和 MT 表达均有高度显着上调（P <0.05）。例如，在 4.25 ppm 浓度下，第 2 周和第 3 周肝脏 GPx 水平显着升高，而在 8.57 ppm 浓度下，第 3 周和第 4 周升高；在 4.25 ppm 浓度下，第 1 周、第 2 周和第 3 周肾脏 GPx 水平显着升高，而在 8.57 ppm 浓度下，第 2 周、第 3 周和第 4 周升高。总之，Cr（VI）诱导的氧化应激表现为金鱼组织中 SOD、GPx 和 MT 表达的统计学显着增加；与肝脏相比，肾脏对 Cr（VI）毒性的敏感性相对较高。
