title: Cadmium-induced oxidative cellular damage in human fetal lung fibroblasts (MRC-5 cells).
abstract: Epidemiological evidence suggests that cadmium (Cd) exposure causes pulmonary damage such as emphysema and lung cancer. However, relatively little is known about the mechanisms involved in Cd pulmonary toxicity. In the present study, the effects of Cd exposure on human fetal lung fibroblasts (MRC-5 cells) were evaluated by determination of lipid peroxidation, intra-cellular production of reactive oxygen species (ROS), and changes of mitochondrial membrane potential. A time- and dose-dependent increase of both lactate dehydrogenase leakage and malondialdehyde formation was observed in Cd-treated cells. A close correlation between these two events suggests that lipid peroxidation may be one of the main pathways causing its cytotoxicity. It was also noted that Cd-induced cell injury and lipid peroxidation were inhibited by catalase and superoxide dismutase, two antioxidant enzymes. By using the fluorescent probe 2',7'-dichlorofluorescin diacetate, a significant increase of ROS production in Cd-treated MRC-5 cells was detected. The inhibition of dichlorofluorescein fluorescence by catalase, not superoxide dismutase, suggests that hydrogen peroxide is the main ROS involved. Moreover, the significant dose-dependent changes of mitochondrial membrane potential in Cd-treated MRC-5 cells, demonstrated by increased fluorescence of rhodamine 123 examined using a laser-scanning confocal microscope, also indicate the involvement of mitochondrial damage in Cd cytotoxicity. These findings provide in vitro evidence that Cd causes oxidative cellular damage in human fetal lung fibroblasts, which may be closely associated with the pulmonary toxicity of Cd.
authors.affiliation: School of Public Health, Tongji Medical University, Wuhan, Peoples Republic of China.
authors.forename: C F
authors.initials: CF
authors.lastname: Yang
authors.forename: H M
authors.initials: HM
authors.lastname: Shen
authors.forename: Y
authors.initials: Y
authors.lastname: Shen
authors.forename: Z X
authors.initials: ZX
authors.lastname: Zhuang
authors.forename: C N
authors.initials: CN
authors.lastname: Ong
mesh_terms: D002104:Cadmium / Q000494:pharmacology / Q000633:toxicity*; D002374:Catalase / Q000187:drug effects / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005333:Fetus / Q000166:cytology; D005347:Fibroblasts / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D015227:Lipid Peroxidation / Q000187:drug effects*; D008168:Lung / Q000166:cytology / Q000187:drug effects*; D008564:Membrane Potentials; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000187:drug effects / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D002104:Cadmium; D002374:Catalase; D013482:Superoxide Dismutase