To evaluate the effect of inorganic treatment on the viability of adult neuronal cell, MTT colorimetric assay was next
performed. Treatment of neuronal cells with lead (7 mM)
or mercury (23 μM) for 24 h resulted in ~27.9 and ~29.2%
reductions in metabolic cell viability, respectively (Figures 2A
and 2B). It is noteworthy that the concentration of lead and
mercury treated in neuronal cells were determined based
on the concentrations of metals, which were detectable in
neonatal brain (Figures 1A and 1B). Taken together, these
results strongly suggest that accumulated lead and mercury
in neonatal brain could result in the substantial neuronal cell
death.