Long-term Cytotoxicity Testing of the First Twenty MEIC Chemicals by the Determination of the Protein Content in Human Embryonic Lung Cells

Abstract

Within the framework of the MEIC (the multicentre evaluation of in vitro cytotoxicity) programme, the long-term cytotoxicity of the first twenty MEIC chemicals was investigated on MRC-5 cells. After treatment of the cells with each chemical for six weeks, the PI50 value was determined. The PI50 is the concentration (mM) of test compound required to induce a 50% reduction in total cell protein content. The results were compared with the acute PI50 values previously measured after treatment for 24 hours with the same compounds in Hep G2 cells. A good correlation between these two sets of data (r² = 0.94) was observed, with the exception of digoxin. Together with other preliminary MEIC validation results, this study indicates that a good alternative cytotoxicity test may be found for the prediction of human long-term toxicity.