Modulation of glial cell differentiation by exposure to lead and cadmium

The influence of the neurotoxic agents lead and cadmium on human glioma cells (86HG-39, 87HG-31, 88HG-14, and A172) and rat glioma cells (F98 and RG2) was investigated in vitro by means of immunocytochemistry and growth data. Both heavy metals increased the growth rate, decreased the expression of differentiation markers (glial fibrillary acidic protein, S100 protein), and increased the expression of the malignancy marker transferrin receptor. The results indicate a decrease in the level of differentiation and impairment of glial cell function. Consequently, the neurotoxicity of Pb and Cd may be attributed to direct action not only on neurons but also on glial cells necessary for neuronal function. Possible molecular mechanisms are discussed.