Sunday, September 23, 2012

DNA Damage to Embrioys in Zebrafish from Cobalt exposure

[Seems as though I published this before but I guess not.  This is an important article and relates to the oxidative stress articles I have published previously and that is:  these surgeries cause oxidatve stress which can lead to damage in the DNA...this goes a step further and demonsrtate what that oxidatives stress does to embryos]

2012 Sep 16. [Epub ahead of print]

The Effects of Cobalt on the Development, Oxidative Stress, and Apoptosis in Zebrafish Embryos.


Department of Orthopaedics, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, 1665 Kong-Jiang Road, Shanghai, 200092, China.


Metal-on-metal hip arthroplasty has been performed with increasing frequency throughout the world, particularly in younger and more active patients, including women of childbearing age. The potential toxicity of cobalt exposure on fetus is concerned since cobalt ions generated by metal-on-metal bearings can traverse the placenta and be detected in fetal blood and amniotic fluid. This study examined the effects of cobalt exposure on early embryonic development and the mechanisms underlying its toxicity. Zebrafish embryos were exposed to a range of cobalt concentrations (0-100 mg/L) between 1 and 144 h postfertilization. The survival and early development of embryos were not significantly affected by cobalt at concentrations <100 μg/L. However, embryos exposed to higher concentrations (>100 μg/L) displayed reduced survival rates and abnormal development, including delayed hatching, aberrant morphology, retarded growth, and bradycardia. Furthermore, this study examined oxidative stress and apoptosis in embryos exposed to cobalt at concentrations of 0-500 μg/L. Lipid peroxidation levels were increased in cobalt-treated embryos at concentrations of 100 and 500 μg/L. The mRNA levels of catalase, superoxide dismutase 2, p53, caspase-3, and caspase-9 genes were upregulated in a dose-dependent manner. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assays also revealed abnormal apoptotic signals in the brain, trunk, and tail when treated with 500 μg/L cobalt. These data suggest that oxidative stress and apoptosis are associated with cobalt toxicity in zebrafish embryos.

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