Preliminary investigation on the cytotoxicity of tellurite to cultured HeLa cells.

Cytotoxicity of tellurite to cultured HeLa cells was examined by cell viability, lactate dehydrogenase (LDH) assay, and tellurite uptake. The experimental results show that the toxicity of tellurite depends on its concentrations and exposure time. HeLa cells exposed to tellurite for 2 h at 9.1 x 10(-4) to 4.5 x 10(-3) mmol/L did not exhibit cytotoxic effects as measured by cell viability. Exposure to tellurite for 24 h at the same concentrations markedly reduced the cell viability to 57% of the control during the first 5 minutes. Additionally, HeLa cells incubated at 2.7 x 10(-2) to 0.27 mmol/L of tellurite for 2 h retained 53% to 67% of cell viability. Even after 24 h exposure, the HeLa cells incubated at 9.1 x 10(-4) to 4.5 x 10(-2) mmol/L of tellurite still retained 57% to 66% of cell viability. Furthermore, tellurite toxicity was also demonstrated in supernatant of the culture at 37 degrees C by LDH assay. It was found that exposure to tellurite for 90 minutes did not stimulate LDH activity. However, tellurite uptake seems to be more sensitive than the cell viability and LDH activity release tests, as it significantly increases with the increasing of exposure time.