Influence of triethyl lead on neurofilaments in vivo and in vitro

The influence of triethyl lead chloride (TriEL) on the organization of neurofilaments in vivo was studied by indirect immunofluorescence microscopy employing mouse neuroblastoma cells (Neuro-2a). TriEL induces perinuclear coil formation of neurofilaments in those cells. The rearrangements observed are not correlated with significant changes of the microtubular system. Cells in which the microtubular network was stabilized by Taxol treatment prior to incubation with TriEL even show the rearrangement of the neurofilaments. The effect of TriEL is reversible. In vitro, the effect of TriEL on isolated neurofilaments and on filament formation as well as on the structure of preformed filaments was investigated by electron microscopy. If isolated neurofilaments from porcine spinal cord are incubated in the presence of TriEL, they show constrictions and bulges. Additionally, many fragments are seen. If preformed filaments are treated with TriEL, unraveling of fibers into protofilamentous strands is observed. The assembly of neurofilaments in vitro is disturbed in the presence of TriEL. The interaction of TriEL with neurofilaments in vivo is likely to be at least partly responsible for the neurotoxicity of TriEL.