The aim of this work was to study the in vitro effect of ozone on the
70 kDa family of inducible heat shock proteins (HSPs70). We also perfo
rmed tests to investigate possible toxic effects of ozone at the diffe
rent doses employed. In human haematic mononucleated cells ozone at do
ses up to 20 mu g/ml had no toxic effects and induced biosynthesis of
the HSPs70. Biosynthesis of these proteins was greater at 40 mu g/ml.
In murine macrophages testing with tetrazolium salt (MTT) neutral red,
and 2-deoxy-D-[l-H-3]glucose uptake and study of the cell morphology
showed a remarkable resistance or no toxic effects at a dose of 100 mu
g/ml also. Melanoma B16 murine cells assayed with the MTT test demons
trated less resistance to the toxic effects of ozone than normal cells
. These results provide indications relevant to the problems of ozone
therapy.