Fu Jun, Liang Xing, Chen Yue, Tang Li, Zhang Qing-hong, Dong Qiang
Key Laboratory of Oral Biomedical Engineering of Chinese Ministry of Education, West China College of Stomatology, Sichuan University, Chengdu, Sichuan 610041, People's Republic of China.
Cell Biol Toxicol. 2008 Jun;24(3):201-12. doi: 10.1007/s10565-007-9029-7. Epub 2007 Nov 20.
It has been documented that medical prosthetic alloys release metal ions into surrounding tissues and cause cytotoxicity, but the mechanisms remain undefined. In that regard the cellular oxidative stress may be a common pathway in cellular responses to metal ions. The objective of this study was to approach the hypothesis that oxidative stress mediates chromium-induced cytotoxicity in rat calvarial osteoblasts. Osteoblasts were exposed to different concentrations of Cr6+ or Cr3+ (5-20 microM) in the presence or absence of the antioxidant N-acetyl-cysteine (NAC; 1-5 mM). Cellular viability, differentiation, and intracellular ultrastructural alterations were evaluated by MTT assay, alkaline phosphatase (ALP) activity assay, and transmission electron microscopy. Cellular oxidative stress was evaluated by intracellular reactive oxygen species (ROS) production. ROS production was monitored by the oxidation-sensitive fluorescent probe 2'7'-dichlorofluorescin diacetate (DCFH-DA). A time- and concentration- dependent increased cytotoxicity, time-dependent increased intracellular ROS production were indicated on exposure to Cr6+. Pretreatment of osteoblasts with 1-5 mM NAC afforded dose-dependent cytoprotective effects against Cr6+-induced cytotoxicity in osteoblasts. NAC decreased the level of intracellular ROS induced by Cr6+, too. While Cr3+ and NAC did not have any significant effects on osteoblasts (5-20 microM). These results suggest that oxidative stress is involved in Cr6+-induced cytotoxicity in osteoblasts, and NAC can provide protection for osteoblasts against Cr6+-induced oxidative stress. Cr3+ (5-20 microM) have no significant cytotoxicity in osteoblasts based on the results of this study.
已有文献记载，医用修复合金会向周围组织释放金属离子并导致细胞毒性，但具体机制仍不明确。在这方面，细胞氧化应激可能是细胞对金属离子反应的共同途径。本研究的目的是探讨氧化应激介导铬诱导大鼠颅骨成骨细胞细胞毒性的假说。在存在或不存在抗氧化剂N-乙酰半胱氨酸（NAC；1-5 mM）的情况下，将成骨细胞暴露于不同浓度的Cr6+或Cr3+（5-20 microM）。通过MTT法、碱性磷酸酶（ALP）活性测定和透射电子显微镜评估细胞活力、分化和细胞内超微结构改变。通过细胞内活性氧（ROS）生成评估细胞氧化应激。ROS生成通过氧化敏感荧光探针2'7'-二氯荧光素二乙酸酯（DCFH-DA）监测。暴露于Cr6+后，显示出时间和浓度依赖性的细胞毒性增加以及时间依赖性的细胞内ROS生成增加。用1-5 mM NAC预处理成骨细胞对Cr6+诱导的成骨细胞细胞毒性具有剂量依赖性的细胞保护作用。NAC也降低了Cr6+诱导的细胞内ROS水平。而Cr3+和NAC对成骨细胞（5-20 microM）没有任何显著影响。这些结果表明，氧化应激参与了Cr6+诱导的成骨细胞细胞毒性，并且NAC可以为成骨细胞提供针对Cr6+诱导的氧化应激的保护。基于本研究结果，Cr3+（5-20 microM）在成骨细胞中没有显著的细胞毒性。
