In vitro tests to detect chemical carcinogens

Cytotoxic Effects of Paracetamol in Vitro: The Effects of an S9 Fraction

The cytotoxic effects of short-term and long-term exposure of HeLa cells to paracetamol (acetaminophen) were assayed by total protein content reduction (microprotein assay) and by [14C]-L-leucine incorporation into macromolecular acid-insoluble cell fraction. The level of total protein content was followed over 72 hours and the level of [14C]-L-leucine incorporation over 24 hours, after paracetamol treatment. Statistical evaluation did not show a significant difference between results obtained by these two methods. In addition, the influence of S9 fraction on [14C]-L-leucine incorporation and the growth activity of paracetamol-treated HeLa cells were assayed. In these experiments, short-term paracetamol treatments (2 hours in phosphate buffered saline), were used. Statistical analysis of the data did not show an increase in paracetamol-induced cytotoxicity in the presence of the S9 fraction; on the contrary, a protective effect of S9 fraction on paracetamol-treated cells was found.