engleski

Method for assessment of intracellular level of cadmium and thallium

Cadmium (Cd) and thallium (Tl) are highly toxic metals. Their deleterious effect on human health is well established, and their mechanisms of toxicity are still explored on in vitro model. To accurately link specific change in the cell with the exposure to metals, the intracellular level of metal should be determined. Therefore the aim of this study was to develop method that will enable accurate determination of intracellular level of Cd and Tl of cells treated with these two metals. Cells (HepG2 ; at planting density of 2.5x105 cells/mL) were treated with Cd or Tl (1 and 10 mg/L) for 24 h. Afterwards, cells were washed in PBS buffer and resuspended in 0.5 mL of PBS buffer. Cells were digested with equal volume of 2% HNO3. For monitoring intracellular level of Cd and Tl, ICP-MS (ELAN DRC-e, Perkin Elmer, Singapore 2008) was applied. For validation experiments Cd and Tl standards as well as reference materials CRM DORMA 4 Fish protein (NRC Canada) for Cd and NCS ZC 73028 Rice (China National Analysis Center) for Tl were used. In concentration range tested (0.2–200 μ g/L) developed method was linear and correlation coefficient (R2) for Cd was 0.9999 with intercept 0.0732 while for Tl was 1.00009 with intercept - 0.1497. Limit of detection (LOD), repeatability and trueness for Cd were 0.020 μg/L, 2.9%, 96.6% and for Tl 0.097 μg/L, 3.7% and 102%, respectively. Developed method was applied to cells treated with Cd or Tl. The intracellular level of Cd and Tl was concentrationdependent. At higher concentration higher intracellular level of Cd and Tl were detected. However, higher uptake of Cd in comparison to Tl was observed (at concentration level 1 mg/L ; 10% for Cd in comparison to 1% for Tl) that can explain higher toxicity of Cd to cells. In conclusion, validation parameters indicate that developed method is reliable and accurate for intracellular assessment of Cd and Tl and enabled following low levels of Cd and Tl within the cell. Furthermore, from obtained results it can be concluded that cells more readily accumulate Cd than Tl.

HepG2 cells ; ICP-MS ; heavy metals

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