Velma Venkatramreddy, Tchounwou Paul B
Environmental Toxicology Research Laboratory, NIH-RCMI Center for Environmental Health, College of Science, Engineering and Technology, Jackson State University, Jackson, MS, USA. ; Department of Biochemistry, the University of Mississippi Medical Center, Jackson, MS, USA.
Biomark Insights. 2013 Apr 25;8:43-51. doi: 10.4137/BMI.S11456. Print 2013.
Chromium (Cr) is an abundant element in the Earth's crust. It exhibits various oxidation states, from divalent to hexavalent forms. Cr has diverse applications in various industrial processes and inadequate treatment of the industrial effluents leads to the contamination of the surrounding water resources. Hexavalent chromium (Cr (VI)) is the most toxic form, and its toxicity has been associated with oxidative stress. The present study was designed to investigate the toxic potential of Cr (VI) in fish. In this research, we investigated the role of oxidative stress in chromium-induced genotoxicity in the liver and kidney cells of goldfish, Carassius auratus. Goldfish were acclimatized to the laboratory conditions and exposed them to 5% and 10% of 96 hr-LC50 (85.7 mg/L) of aqueous Cr (VI) in a continuous flow through system. Fish were sampled every 7 days for a period of 28 days to analyze the lipid hydroperoxides (LHP) levels and genotoxic potentials in the liver and kidney. LHP levels were analyzed by spectrophotometry while genotoxicity was assessed by single cell gel electrophoresis (comet) assay. LHP levels in the liver increased significantly at week 1, followed by a decrease. LHP levels in the kidney increased significantly at weeks 1, 2, and 3, and decreased at week 4 compared to the control. The percentage of DNA damage increased in both liver and kidney at both test concentrations. The results clearly indicate that Cr (VI) induces significant levels of DNA damage in liver and kidney cells of goldfish. The induced LHP levels in both organs were concentration-dependent and were directly correlated with the levels of DNA damage. The two tested Cr (VI) concentrations induced significant levels of oxidative stress in both organs, however the kidney appears to be more vulnerable and sensitive to Cr-induced toxicity than the liver.
铬（Cr）是地壳中一种含量丰富的元素。它呈现出从二价到六价的多种氧化态。铬在各种工业过程中有多种应用，而工业废水处理不当会导致周围水资源受到污染。六价铬（Cr(VI)）是毒性最强的形式，其毒性与氧化应激有关。本研究旨在调查Cr(VI)对鱼类的潜在毒性。在这项研究中，我们研究了氧化应激在铬诱导的金鱼（Carassius auratus）肝脏和肾脏细胞遗传毒性中的作用。金鱼适应实验室条件后，在连续流动系统中使其暴露于96小时半数致死浓度（85.7毫克/升）的5%和10%的水溶性Cr(VI)中。在28天的时间里，每隔7天对鱼进行采样，以分析肝脏和肾脏中的脂质过氧化氢（LHP）水平和遗传毒性潜力。通过分光光度法分析LHP水平，而通过单细胞凝胶电泳（彗星）试验评估遗传毒性。肝脏中的LHP水平在第1周显著升高，随后下降。与对照组相比，肾脏中的LHP水平在第1、2和3周显著升高，在第4周下降。在两种测试浓度下，肝脏和肾脏中的DNA损伤百分比均增加。结果清楚地表明，Cr(VI)在金鱼的肝脏和肾脏细胞中诱导了显著水平的DNA损伤。两个器官中诱导的LHP水平呈浓度依赖性，并且与DNA损伤水平直接相关。两种测试的Cr(VI)浓度在两个器官中均诱导了显著水平的氧化应激，然而，肾脏似乎比肝脏对铬诱导的毒性更脆弱、更敏感。
