Neurotoxicity of β-HgS differs from environmental mercury pollutants (MeHgCl and HgCl2) in Neuro-2a cell

beta-HgS, differing from environmental mercury pollutants (MeHgCl and HgCl2) in chemical form, is used as traditional medicine in Asian countries for thousands of years. In this study, Neuro-2a cells were exposed to beta-HgS, MeHgCl and HgCl2 (5 mu M) for 6-24 h. The cell viability of beta-HgS was higher than MeHgCl with 25.9% and 72.4% in 12 h and 24 h respectively. As the incubation time increased, MeHgCl had obvious damage to cell morphology, decreased the ratio of Bcl-2 and Bak and increased the expressions of TNF-alpha, IL-6 and IL-1 beta significantly. Furthermore, the expressions of IL-1 beta and IL-6 in HgCl2 group were increased significantly in 6 h and 24 h. The apoptotic rates in MeHgCl and HgCl2 group were respectively higher than beta-HgS with 32.2% and 7.30% in 24 h. Our findings indicate that beta-HgS is much less neurotoxicity than MeHgCl and HgCl2 in Neuro-2a cells.