Abstract：Objective To investigate the effects of lead (Pb) exposure on neurons and choroid plexus epithelial cells and its molecular mechanisms. Methods Rat pheochromocytoma PC12 cells and choroidal epithelial Z310 cells were cultured in vitro. Methyl thiazolyl tetrazolium (MTT) assay was performed to determine the proper Pb exposure dose (the lowest dose affecting the cell viability) by treating the cells with 0-50 μmol/L lead acetate for 24 and 48 hours. Cell apoptosis was determined by TUNEL assay following Pb exposure for 48 hours. Western blot was used to detect the protein levels of bcl-2, bax and caspase-3 at the 24th and 48th hours. Results The viability of both PC12 and Z310 cell lines was significantly decreased when they were treated with 10 μmol/L Pb and higher doses, so 10 μmol/L was chosen as the working concentration of Pb exposure. Compared with the normal controls, the number of TUNEL positive cells was significantly increased in PC12 cells following Pb exposure (P<0.05), while no obvious cell apoptosis was observed in Pb-treated Z310 cells (P>0.05). Western blot showed that 10 μmol/L Pb exposure resulted in increased ratio of bax/bcl-2 and elevated expression of cleaved caspase-3 protein in PC12 cells at both the 24th and 48th hours (P<0.05); however, the bax/bcl-2 ratio and cleaved caspase-3 protein level were not significantly changed following the Pb exposure (P>0.05). Conclusions Lead-induced damage in various brain cells may involve different pathways and mechanisms.It induces apoptosis in PC12 cells through mitochondrial pathway, but can not activate apoptosis signal in Z310 cells.
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2017, Vol. 24 
