Cultured brain cells treated with Pb (4.8 and 7 mM for
50 and 100 ppm groups, respectively) and Hg (2.4 and 23
μM for 50 and 80 ppm groups, respectively) for overnight,
were then fixed, incubated with anti-tubulin and anti-tau
antibody and subsequently visualized with ABC reagent (Vector
Laboratory, Burlingame, USA). All imaging data were processed
with light-microscopy (×200) (PC-2, Olympus, Tokyo, Japan).