Evaluation of the spindle-inhibiting effect of Ni++ by quantitation of chromosomal super-contraction.

In vitro exposure of human lymphocytes to spindle inhibitors reduce the average chromosome length (Andersen and Rønne, 1981, 1983. Andersen et al 1983). In this report chromosome length measurements were used for indirect but quantitative evaluation of the effects of Ni++ on spindle function. In two donors 4 h or 20 h exposure of phytohemagglutinin stimulated peripheral lymphocyte cultures to 10(-3) M but not 10(-4) M Ni++ induced statistically significant reductions in average chromosome length, indicating that Ni++ is a powerful spindle inhibitor in a narrow concentration range just below the lethal concentration. Although systemic effects are unlikely to occur, local effects induced by Ni++ released after pulmonary deposition of Ni containing dusts cannot be ruled out. Spindle dysfunction may result in aneuploidy. The significance of the finding reported here in relation to nickel carcinogenicity is presently unknown.