EFFECT OF DIFFERENT OXIDATION-STATES OF CHROMIUM IN CAUSING CHROMOSOME ALTERATIONS IN CULTURED CHO CELLS

Four chromium salts with different oxidation states were tested for their influence in causing chromosome aberrations and sister-chromatid exchange in Chinese hamster ovary cells in vitro. Cell cultures were treated with CrO3, K2Cr2O7, CrCl2 and Cr(NO3)3.9H2O at concentrations of 10(-7), 10(-6), 10(-5) and 10(-4) M for the aberration assay, and 10(-8), 10(-7), 10(-6) and 10(-5) M for the sister-chromatid exchange assay. It was noticed that Cr (VI) compounds - CrO3 and K2Cr2O7 - considerably enhanced the frequencies of aberrations and sister-chromatid exchanges compared to the control cultures. CrCl2 and Cr(NO3)3.9H2O - Cr (II) and Cr (III) respectively - caused a slight increase in sister-chromatid exchange rates, but the frequencies of aberrations were almost unchanged compared to the controls. These investigations indicate a definite link between the metals and changes produced in the mammalian chromosomes, reaffirming the evidence of carcinogenic potential of Cr (VI) observed by other investigators.