Effects of methylmercury(II) on the viability of HeLa S3 cells

Abstract

HeLa S3 cells were incubated with varying concentrations of CH 3HgOH for varying periods of time and the viability of the cells was determined by using the trypan blue dye exclusion test. Cell viability was found to decrease “cooperatively” with increasing CH 3Hg(II) concentration in the medium. Below a certain “threshold” value of the organomercurial, viz., at CH 3Hg(II) concentrations of 1 μ m and below, the cells remain alive and exhibit the viability of the control, whereas at CH 3Hg(II) concentrations of 10 μ m and above, rapid cell death occurs. The kinetics of the cell death as a function of organomercurial concentration was determined, as was the ability of the cells to recover from injury once the toxicant has been removed. The effect of methylmercury on the mitotic pattern of the cells was also evaluated. At CH 3Hg(II) concentrations of 1 μ m and below, the mitotic coefficient was increased by a factor of 4 over that of untreated cells after 24 hr of incubation. Treated cells became arrested preferentially during the early stages of mitosis. However, higher methylmercury concentrations, viz., 10 μ m and above, caused coagulation necrosis in the cells and no chromosome spreads could be obtained. The viability phenomena observed in this study suggest that the plasma membrane of the cells serves as the primary site of the organomercurial attack at lethal toxicant concentrations.