HSP72 MESSENGER-RNA PRODUCTION IN CULTURED HUMAN-CELLS SUBMITTED TO NONLETHAL AGGRESSION BY HEAT, ETHANOL, OR PROPANOL - APPLICATION TO THEDETECTION OF LOW CONCENTRATIONS OF CHROMIUM(VI) (POTASSIUM DICHROMATE)

The HT29 and HepG2 human cell lines have been shown to express stress proteins (heat shock proteins, HSP) when submitted to a variety of sub lethal environmental aggressions. In the present study, these cells we re submitted to standardized mild aggression by heat, ethanol, or prop an-1-ol in vitro. Subsequent formation of the hsp72 mRNA was measured by a very specific RNase protection method using a radiolabeled antise nse RNA probe. The accumulation of the mRNA coding for the HSP72 stres s proteins was found to be maximum within 3 h after the aggression. Re sults were obtained faster and were much more interpretable than those from the classical method involving the autoradiography of electropho retically separated S-35-labeled proteins, especially in the case of v ery weak, threshold-level, aggressions. When this model was used as a biological system for the detection of low concentrations of chromium( VI) (Cr2O72-), it was possible to detect concentrations as low as 0.5 mu mol/L. This indicates that measuring indices of stress induction in human cultured cells can be several orders of magnitude more sensitiv e than the commercial Microtox assay used for detecting low levels of pollution.