Methylmercury induces neurite degeneration in primary culture of mouse dopaminergic mesencephalic cells

Methylmercury cation (MeHg) is an hazardous environmental pollutant with neurotoxic action. Little is known about the effects of MeHg on catecholaminergic neurons. In the present study we have used epifluorescence microscopy and confocal microscopy to investigate the alterations induced by MeHg in primary DA (dopaminergic) cells isolated from the ventral mesencephalon of CD-1 embryonic mice and cultured for six days in vitro. DA cells were identified in the multi-culture by immunocytochemistry using a tyrosine-hydroxylase antibody. The morphometric analysis of DA neurons exposed to 1 muM MeHg demonstrated a striking decrease in the number of neurites, indicative of cytoskeletal alteration. In addition, DA neurons displayed cell shrinkage and a significant increase of nuclei with chromatin condensation. Based on these results it is concluded that MeHg is highly toxic to primary DA neurons.